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Abstract

Hurdle technology is used in industrialized as well as in developing countries for the gentle but effective preservation of foods. Hurdle technology was developed several years ago as a new concept for the production of safe, stable, nutritious, tasty and economical foods. Previously hurdle technology, i.e., a combination of preservation methods, was used empirically without much knowledge of the governing principles. The intelligent application of hurdle technology has become more prevalent now, because the principles of major preservative factors for foods (e.g., temperature, pH, aw, Eh, competitive flora), and their interactions, became better known. Recently, the influence of food preservation methods on the physiology and behavior of microorganisms in foods, i.e. their homeostasis, metabolic exhaustion, stress reactions, are taken into account, and the novel concept of multi-target food preservation emerged. The present contribution reviews the concept of the potential hurdles for foods, the hurdle effect, and the hurdle technology for the prospects of the future goal of a multi-target preservation of foods

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... This technology utilizes elevated hydrostatic pressure at levels typically from 100 to 800 MPa for ensuring the microbial safety of various food commodities including ready-to-eat products [15,16]. To ensure decontamination efficacy and preserve the quality and organoleptic properties of products, the application of multiple hurdle technology is preferred, where instead of reliance on one treatment as a hurdle, a combination of them is utilized to ensure the safety and quality of processed commodities [17,18]. ...
... However, it is noteworthy that the temperature of 60 °C is not necessarily sufficient for thermal processing to ensure the safety of a product. This study used this temperature as a hurdle in the context of multiple hurdle technology for ensuring the safety of the product [17,23]. This temperature is considered lower than typical pasteurization ...
... However, it is noteworthy that the temperature of 60 • C is not necessarily sufficient for thermal processing to ensure the safety of a product. This study used this temperature as a hurdle in the context of multiple hurdle technology for ensuring the safety of the product [17,23]. This temperature is considered lower than typical pasteurization temperatures; as an example, fluid milk is heated to at least 72 • C for 15 s during pasteurization [24], and according to the U.S. Food and Drug Administration, food containing raw shell eggs (broken for immediate use) will need to be heated to 68 • C for 17 s [25]. ...
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The current study investigated the impact of treatments with elevated hydrostatic pressure (500 MPa) for inactivation of Listeria monocytogenes on smoked rainbow trout (Oncorhynchus mykiss) at high and low inoculation levels. The temperature values of the trials were set at 4.4 and 60.0 °C, adjusted with a circulating water bath connected to a stainless steel jacket surrounding the pressure processing chamber. Before pressure processing, the counts (selective counts of PALCAM, mean ± SD) of L. monocytogenes were 6.45 ± 0.1 log CFU/g and were reduced (p < 0.05) to 3.72 ± 0.3, and <1.48 ± 0.8 log CFU/g after 10 min of treatment at 4.4 and 60.0 °C, respectively. Treatments of low inoculation level samples were similarly efficacious and resulted in a reduction (p < 0.05) of the pathogen to 1.62 ± 0.3 and <0.82 ± 0.0 log CFU/g for treatments at 4.4 and 60.0 °C, respectively. At 4.4 °C, linear D-value and non-linear kmax1 were 8.68 and 0.50, and 5.81 and 2.41 for high-inoculation and low-inoculation samples, respectively. Application of hydrostatic pressure at 500 MPa at cold and elevated temperatures was efficacious for up to 5.03 log CFU/g reduction of L. monocytogenes, illustrating the potential for further adaptation of this technology.
... The plates were observed for growth. The absence of growth in the extracts after incubation indicates sterility and evaluated for antimicrobial activity as indicated in CLSI guidelines [39]. ...
... The modern antibiotic disc employed for this work was Ciprofloxacin (5μg/disc), as a control. This was done in accordance with the CLSI guideline protocols [39]. ...
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Plant products are generally useful for medicinal purposes, one of which is the noni plant. Noni or pace (Morinda citrifolia L.) fruit juice was extracted using aqueous and methanol solvents, then fermented and screened for the presence or absence of bioactive constituents (phytochemicals) using the modified standard procedures. The major phytochemical constituents revealed were alkaloids, anthraquinones, cardiac glycosides, and flavonoids, phenolic compounds, saponins, tannins, reducing sugar, saponnins, carbohydrate and terpenoids. Bacterial cell viability and MIC values were also determined by turbidity test. The lowest concentration of the extract with clear suspension was considered the MIC values. The lowest concentration of the extract in the post-incubation suspensions which did not harbour any bacterial growth upon spotting on MHA after overnight incubation at 37° C was considered the MBC values. The test was performed in triplicates alongside antibiotics ciprofloxacin (5μg) as a positive control at a concentration of 0.1mg/ml. Antibacterial activity was perfumed against three bacteria (Salmonella typhi, Escherichia coli, and Staphylococcus aureus) by agar-well diffusion method. Activity was observed for both methanolic and aqueous extracts of Morinda citrifolia L. fruit juice against the organisms tested. The extracts had both bacteriostatic and bactericidal activity against the test microorganisms. The Minimum Inhibitory Concentration (MIC) test revealed that the bacterial isolates were inhibited between concentrations of 50mg/ml and 25mg/ml for the methanolic extract, and between 100mg/ml and 50mg/ml for the aqueous extract of the fermented fruit juice. The extract was bactericidal from the range of 100mg/ml to 200mg/ml for both extracts, though with the exception of S. aureus which was bactericidal at 50mg/ml for methanolic extract.
... Changes in consumer demand for more natural and minimally preserved seafood products drive the development of more lightly processed products (Abel et al., 2022;Carlucci et al., 2015;Speranza et al., 2009). Hurdle technology, which is a method of controlling food pathogens in food, needs to be implemented to meet quality, safety and sustainability issues, and several new interesting combinations of technologies have been tested/developed in recent years (Abel et al., 2019a;Lerfall et al., 2018b;Rosnes et al., 2011;Rosnes and Skipnes, 2018;Singh and Shalini, 2016). ...
... minimal heat processing, non-thermal processing or modifed atmospheric packaging) has been developed and applied in the food industry to produce fresh-like products with longer shelf-life and increased product safety (Abel et al., 2019a(Abel et al., , 2019b(Abel et al., , 2022Ohlsson, 1994;Ohlson and Bengtsson, 2000;Rosnes et al., 2011;Rosnes and Skipnes, 2018;Sivertsvik et al., 2002). Minimal processing of food often requires multiple sub-lethal processes, or hurdles, to achieve a similar level of microbial control as are obtained in traditional processing methods using a single lethal process (Rosnes et al., 2011;Singh and Shalini, 2016;Abel et al., 2022). For example, proper rice acidifcation combined with low storage temperature (≤4°C) was required to prevent the growth of Aeromonas spp. in retail sushi (Hoel et al., 2018). ...
Chapter
Aquatic Food Security explores a range of issues related to this subject using global examples to illustrate both strengths and weaknesses within the existing aquatic food supply chain.
... One method in safeguarding against bacterial infections is through the use of a hurdle effect technology (HET) (Chapman and Ross, 2009), which combines the application of several protective methods (either physical or chemical in nature) that are regarded as having bactericidal or bacteriostatic effects (Walkling-Ribeiro et al, 2011;Narayanan et al, 2013;Singh and Shalini, 2016;Munoz et al, 2017). Disturbance of microorganism homeostasis is a critical principle of food preservation, but microbial stress reactions may compromise food preservation, while, on the other hand, metabolic exhaustion of microorganisms in HET-processed food or food products fosters food preservation (Singh and Shalini, 2016). ...
... One method in safeguarding against bacterial infections is through the use of a hurdle effect technology (HET) (Chapman and Ross, 2009), which combines the application of several protective methods (either physical or chemical in nature) that are regarded as having bactericidal or bacteriostatic effects (Walkling-Ribeiro et al, 2011;Narayanan et al, 2013;Singh and Shalini, 2016;Munoz et al, 2017). Disturbance of microorganism homeostasis is a critical principle of food preservation, but microbial stress reactions may compromise food preservation, while, on the other hand, metabolic exhaustion of microorganisms in HET-processed food or food products fosters food preservation (Singh and Shalini, 2016). ...
Article
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Escherichia coli O157:H7 is the etiological agent of severe intestinal infection in humans causing foodborne illness through consumption of contaminated raw food. The study tested bactericidal activity against E. coli O157:H7 of citric acid solution alone or in combination with three other generally recognized as safe (GRAS) compounds, four common household wash solutions and a commercial wash solution. Citric acid solution (0.112 mg/ml) was more effective, achieving 1, 6 and 12 log10 reduction in 3, 19 and 38 minutes, respectively compared to a commercial wash solution, with 1 log10 reduction in 15 minutes. Bactericidal efficacy of the citric acid solution was highly improved when supplemented with GRAS compounds, namely, ethylenediaminetetraacetic acid (0.01 g/ml), L-ascorbic acid (0.013 g/ml) and sodium lauryl ether sulfate (0.031 g/ml), at 4°C and 25°C, with >3 log10 reduction in 5 minutes; the efficacy was slightly reduced at 40°C. However, household wash solutions (distilled water, 0.04% (v/v) hydrogen peroxide, 20.0% (w/v) sodium chloride, and 2.50% (v/v) vinegar) were markedly less effective, with 1 log10 reduction in 259-1,550 minutes. These findings indicate a solution of citric acid together with other GRAS compounds have the potential as a superior disinfectant or preservative in inhibiting E. coli O157:H7 growth compared to common household and commercial disinfectant wash solutions. This study is critically relevant to ongoing strategies in diminishing the risk of coliform contamination in products.
... However, applying food safety systems in an improperly designed industrial unit can lead to non-compliances, resource misallocation, and unnecessary costs. Other studies refer to the diagnosis of already implemented food safety systems (Jespersen et al. 2016;Njage et al. 2018;Ramaswamy et al. 2019) or to the design of processes using GHP as overarching requirements (Kubo et al. 2021;Singh and Shalini 2016;Talib, Ali, and Idris 2013), however, without presenting prescriptions or solutions for an evolution in the process design with a focus on food safety. ...
Article
Process design strategies are important to prevent or reduce food safety risks in production systems. In this sense, the Codex Alimentarius presents a set of principles for good hygiene practices to guide food producers. However, studies in food safety often focus on analyzing and controlling implemented production processes without a policy of designing them with a preventive logic, leading to resource misallocation and noncompliance. This study aims to gather and analyze techniques, drivers, challenges, and research opportunities for food safety-driven process design. A systematic literature review was carried out following three steps: (i) Data collection, including 52 studies; (ii) Bibliometric analysis; and (iii) Content analysis, identifying techniques, drivers, challenges, and research opportunities. Three main themes in the subject were identified: process assessment models, risk assessment, and whole-chain traceability. Eleven design techniques were identified and compared according to their typology, structure, and coverage of themes addressed by the Codex Alimentarius. There is a gap in techniques addressing employee competence and personal hygiene. We suggest developing a tool encompassing the Codex Alimentarius good hygiene practices themes in process design to guide food safety-driven process development.
... Currently, there is the need to find new techniques which not only preserves foods but that also ensure the least possible damage to the product nutrients. Hurdle technology is a strategic mix of low-intensity preservation factors (reduction of water activity and pH, application of heat treatments and antimicrobial compounds, etc.) that provides a suitable alternative to ensure food preservation compared to the use of a single high-intensity process (Mechmechani et al. 2022;Singh and Shalini 2016). This strategy has been widely adopted in the current food technology industry since it allows the use of several minimal-processing techniques, which are relatively mild and non-energetically intensive, that pose cumulative "hurdles" which prevent food contamination and spoilage in a very efficient way. ...
Chapter
Currently, disease transmission through contaminated foods as well as multiple antibiotic resistance of microbial pathogens is considered a global threat to public health. In addition, the fact that modern food consumers are looking for products with the least amount of food additives, has prompted the food industry to seek for new preservation alternatives. Considering this, the use of bioprotective bacteria as food preservation agents has been widely reported in the scientific and technological literature, with lactic acid bacteria being the microbial group most predominantly employed in current developments. Lactic acid bacteria can produce several antimicrobial compounds such as acid, diacetyl, hydrogen peroxide, antimicrobial peptides, among others. In this regard, antimicrobial peptides can be considered as a promising strategy to address these problems because they present high specificity against targeted microorganisms, elevated thermal stability, fast and effective inhibitory action, and low probability of developing microbial resistance. In this review, we report the current research on the basis, classification, benefits, and various forms of application of antimicrobial peptides from lactic acid bacteria, mainly in the hurdle technology for food biopreservation and discuss the main safety considerations involved in the practical use of these antimicrobial agents.
... Hurdle technology, advocates the deliberate combination and establishment of series of preservative factors which combines processing and packaging technologies, with chemical factors to preserve and improve food quality. Potential hurdles for improving the quality of foods have been described in the literature [173][174][175][176][177]. Temperature, water activity, acidity (pH), redox potential, preservatives, and competitive micro-organisms are the most important hurdles [140]. ...
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The article seeks to thoroughly review the published literature and diverse awareness regarding natural waste including agricultural residues and food debris. Attention is drawn to current-day techniques of natural waste recovery. The concept of natural waste and the developed new ways of recovery are reviewed to promote knowledge transfer of modern green technologies for sustainable society and new processes that may be incorporated as a starting step or intermediate step during recovery of agro-industrial residues for better production of added-value products. The approach is directed toward maximizing the value of biomass feedstock, as well as to reduce the environmental impact of the waste. The article focuses on processing routes of natural waste with eco-friendliness by applying various preservation technologies, the conventional and the novel at forefront the improved valorization of by-products that lead to advanced industries including biorefineries. Applications of the produced added-value products are also involved.
... Various studies have shown that hurdle technology is more effective than individual treatments in diminishing MOs while maintaining the quality of bread and bakery products and extending their shelf life. [92] Ethanol-based hurdle technology Using ethanol emitters and oxygen absorbers has indicated an increase in the microbial shelf-life of packed sliced rye bread from 8-12 to 26-27 days. [93] No change in texture and moisture content of bread slices has been reported. ...
... The reason for the hurdle approach was EB radiation limits of �10 kGy recommended by FAO/WHO are not sufficient to reduce spore population by more than 3-4 log cycles, hence not adequate to ensure food sterilization and safety (De Lara et al., 2002). Nowadays, non-thermal technologies and thermal treatments are employed as hurdle techniques to improve inactivation efficacy in food pathogens control Singh & Shalini, 2016). Lowtemperature thermal treatments (40-90 � C) are selected because they produce meat with improved tenderness and better appearance than when cooked at higher temperatures (Dominguez-Hernandez et al., 2018). ...
Article
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The individual and combined effects of electron beam (EB) irradiation and thermal treatments were investigated on Chinese braised beef samples inoculated with Bacillus cereus spores. Log reductions of 1.19, 2.10, and 3.62 log CFU/g were recorded for B. cereus spores after 6, 9, and 12 kGy lone EB doses, respectively. An 85°C thermal treatment at 20 min (H) reduced the spores population by 1.03 log CFU/g. The combination of the thermal and EB irradiation treatments (HEB) of HEB-6 and HEB-9 achieved 1.69 and 2.89 log CFU/g reductions, respectively. The B. cereus spores population was depleted to below the detection limit following HEB-12 treatment. No significant pH change was observed in the treatments except for HEB-12. The hurdle treatment of HEB-12 caused marked changes in color, aroma, and overall acceptability. Although HEB irradiation improved microbial safety, careful selection of approved EB doses can effectively enhance food safety and maintain reasonable quality standards.
... These changes include physiological, biochemical, and biological changes caused by enzymes, changes caused by microbial contamination, as well as chemical and physical changes induced by temperature and humidity variations, all of which can lead to losses in food quality and quantity. Various techniques are used for food storage both domestically and internationally, including refrigeration, modified atmosphere packaging, edible packaging films, high-pressure processing, and gene regulation storage preservation techniques, which can help maintain the quality of food during storage (Iversen et al., 2020;Singh & Shalini, 2016). It is crucial to detect and study the various changes that occur in food during storage, determine appropriate storage methods and conditions, in order to ensure food quality and extend its shelf life. ...
Article
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Food science encounters increasing complexity and challenges, necessitating more efficient, accurate, and sensitive analytical techniques. Mass spectrometry imaging (MSI) emerges as a revolutionary tool, offering more molecular‐level insights. This review delves into MSI's applications and challenges in food science. It introduces MSI principles and instruments such as matrix‐assisted laser desorption/ionization, desorption electrospray ionization, secondary ion mass spectrometry, and laser ablation inductively coupled plasma mass spectrometry, highlighting their application in chemical composition analysis, variety identification, authenticity assessment, endogenous substance, exogenous contaminant and residue analysis, quality control, and process monitoring in food processing and food storage. Despite its potential, MSI faces hurdles such as the complexity and cost of instrumentation, complexity in sample preparation, limited analytical capabilities, and lack of standardization of MSI for food samples. While MSI has a wide range of applications in food analysis and can provide more comprehensive and accurate analytical results, challenges persist, demanding further research and solutions. The future development directions include miniaturization of imaging devices, high‐resolution and high‐speed MSI, multiomics and multimodal data fusion, as well as the application of data analysis and artificial intelligence. These findings and conclusions provide valuable references and insights for the field of food science and offer theoretical and methodological support for further research and practice in food science.
... Hurdle technology, which combines various preservation methods (Aaliya et al., 2021), has been developed as a new approach for producing safe, stable, nutritious, tasty, and cost-effective foods (Singh & Shalini, 2016). Hurdle methods may have a synergistic effect on microbial inactivation (Rahman et al., 2013). ...
Article
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Pathogenic and spoilage bacteria undergo various stresses during food preservation and processing, leading to sublethal injuries. This emphasizes the need for a versatile repair broth. Furthermore, the broth should quickly revive all sublethal cells within 20 min to prevent the proliferation of intact cells for accurate counting. For this purpose, we developed a new repair medium called ERBMn in this study. After systematically examining various factors affecting sublethal injuries in both Escherichia coli K-12 and O157:H7, we identified the freezing and thawing (FT) treatment that resulted in the highest sublethal ratio for each strain. Then, five treatments were used to induce various numbers, types, and degrees of sublethal injuries for both strains: FT, lactic acid (LA), pretreatment with LA followed by FT, concurrent exposure to LA and FT, and pretreatment with FT followed by LA. Our results demonstrated that ERBMn rapidly and completely recovers all sublethal injuries within 20 min. Additionally, we confirmed no observable proliferation after a 20-min incubation in ERBMn. To the best of our knowledge, ERBMn is the first broad-spectrum repair broth for precise enumeration. It is expected to become the preferred repair broth for accurately quantifying E. coli in food for food safety.
... Food preservation can be accomplished through a multitude of strategies, which encompass the reduction in water activity (aw), utilization of low-temperature storage, adjustment of pH levels, incorporation of competitive microflora, and the application of preservatives. The amalgamation of these distinct techniques is recognized as the "hurdle effect", which serves to enhance the overall efficacy of the preservation process [7]. HVEF technology is a novel sterilization technology with low temperature and lower energy consumption [8,9]. ...
Article
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This study investigated the bactericidal effects of ultraviolet (UV) radiation, a high-voltage electric field (HVEF), and their combination on Escherichia coli. The results indicated that UV and combined disinfection were more effective with longer exposure, leading to significant reductions in microbial activity. Specifically, the single UV disinfection alone reduced activity by 3.3 log after 5 min, while combined disinfection achieved a 4.2 log reduction. In contrast, short-term HVEF treatment did not exhibit significant bactericidal effects, only achieving a reduction of 0.17 log in 5 min. Furthermore, prolonged exposure to both UV disinfection and an HVEF was found to damage cell membranes, ultimately causing cell death, while shorter durations did not. Despite rapid cell count decreases, flow cytometry did not detect apoptotic or necrotic cells, likely due to rapid cell rupture. This study suggests that combining UV radiation and an HVEF could be a promising approach for inhibiting bacterial reproduction, with HVEF enhancing UV effects. These findings provide insights for using combined HVEF and UV disinfection in food safety and preservation.
... To counteract the undesirable effect of microbial growth, various food preservation approaches have been developed, namely thermal and chemical methods [7]. The thermal ...
Article
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Despite the technologies applied to food production, microbial contamination and chemical deterioration are still matters of great concern. In order to limit these phenomena, new natural approaches should be applied. In this context, the present study aimed to assess the antioxidant and anti-Clostridial effects of two different polyphenolic extracts derived from olive mill vegetation water, one liquid (LE) and one encapsulated (EE). The extracts have been preliminary characterized using Liquid Chromatography Quadrupole Time-Of Flight spectrometry. The Oxygen Radical Absorbance Capacity method was used to determine the antioxidant capacity, registering a higher value for EE compared to that for LE (3256 ± 85 and 2446 ± 13 µgTE/g, respectively). The antibacterial activity against C. perfringens, C. botulinum and C. difficile was studied by the agar well diffusion method, MIC and MBC determination and a time-kill test. The results confirm that EE and LE are able to limit microbial growth, albeit with minor effects when the phenolic compounds are encapsulated. Further studies are needed to evaluate the possible application of these extracts in food systems.
... The treatments used in these methods are called "hurdle" (Negi 2012).Traditional processes and parameters such as heat treatment, water activity (a w ), acidity, redox potential, preservatives (nitrite, sulfur, sorbate, etc.) are used to ensure food safety and increase the shelf life of foods. While there is only one protection method that causes visible sensory changes in foods, in these methods used in traditional production, two or more protection factors are used together at a low level in barrier technology (Singh and Shalini 2016). Sixty different potential hurdles have been reported for nutrients. ...
Article
Microbial spoilage is a major cause of degradation of the quality characteristics of products such as meat and dairy products or fruits and vegetables. There is a need for eco-friendly practices that prevent microbial growth, while preserving the nutritional value of these products during processing and transportation to the consumer. Traditional food preservation methods, being thermal or chemical techniques, often have a negative impact on the sensory, quality and textural characteristics of the food product. Ozonation is of interest for the food industry using the antimicrobial properties of ozone. It is important for various food products to control the oxidation of lipids. The effects of ozone treatment on lipid oxidation in foods are evaluated in this review. The mechanisms of lipid ozone oxidation are discussed, and the results of different studies are analyzed. It also examines the factors that can affect the efficacy of ozone treatment and the possible risks associated with this technology. Ozone treatment prolongs shelf life, while maintaining product quality and is cost-effective in terms of energy use. It has been shown to inhibit the formation of volatile compounds in some food products, and reduce the occurrence of reactions that reduce the overall quality characteristics of the food, such as lipid oxidation. The effect of ozone application on quality varies with the structure of the food, ozone application time and dose amount.
... This packaging system involves elimination of essentials growth requirements of microbes which can either directly act on them and reduce the microbial counts or indirectly extend their lag phages or reduce their growth rates. The basic principle behind antimicrobial packaging is hurdle technology that involves use of hurdles (pH, heat treatments, water activity, redox potential etc.) in combinations to increase their lethality on the microbes (Singh and Shalini 2016). Antimicrobial packages are comprised of two components the packaging material and the antimicrobial agents. ...
Chapter
The food packaging industry has undergone a revolution, leading to the event of recent packaging materials to reflect advancements in food technology, material and environmental sciences, and consumer preferences. Enormous number of packaging techniques has been developed so that we can enjoy food throughout the year. The new-age packaging can not only provide safety or works as a barrier to the food, rather it is capable of preserving essential nutrients in them and also efficient in incorporating healthy bioactive compounds to food through diffusion. It can also detect any unwanted deterioration of food without opening the package and without using any lab equipment. Of these, novel benefits are contributed by the newly developed packaging technologies like intelligent/smart packaging, active packaging, antimicrobial packaging, use of nanotechnology in packaging, sustainable packaging, and bioactive packaging. This chapter has compiled and interpreted research studies for last 5-years citing principles and applications of these recent innovations in food packaging technologies.
... This is primarily due to the attack of food-borne pathogens and microbes (Istiqomah et al., 2022). This attack can be prevented by mitigating the spread of these undesirable microorganisms using techniques like fermentation, drying, freezing, thermal processing, and chemical additive addition (Ben Said et al., 2019;Qian et al., 2018;Singh and Shalini, 2016). However, these methods have limitations, such as high-temperature processing and prolonged storage, which can lead to the loss of nutritional value and food quality. ...
Article
Active packaging with antimicrobial characteristics can inhibit bacterial growth and prolong the shelf life of packaged food products. Numerous attempts have been made to develop biobased eco-friendly polymer packaging films to minimize the utilization of synthetic antimicrobial packaging. However, polymer-based packaging has limited physio-mechanical properties, making it a poor candidate for packaging applications. In this study, an antimicrobial fibre-reinforced biocomposite was fabricated using rice husk fibre (RH) in the starch matrix to enhance the properties of packaging film. Peppermint essential oil (PEO), extracted from peppermint leaves, was incorporated into the film to enable antimicrobial properties. Rice husk fibre was varied from 10% to 50%, PEO ranged from 1% to 6%, and influence on various properties of biocomposite film was analysed. Developed biocomposite films were evaluated using XRD, FT-IR, SEM, water contact angle, and surface roughness. Furthermore, mechanical properties, water solubility, moisture content, colour properties, and optical barrier properties of biocomposite film were also calculated. In mechanical properties, biocomposite film that has 10% rice husk fibres, and 1% PEO showed the maximum tensile strength and elastic modulus of 2.25 MPa, and 57.4 MPa, respectively. In the biodegradability test, the degradation rate was reduced with reinforcing rice husk fibres and incorporation of PEO. The fabricated biocomposite films exhibit a zone of inhibition against Gram-positive bacteria (S. aureus and B. subtilis) as well as Gram-negative bacteria (E. coli and K. pneumoniae). Moreover, fabricated biocomposite was used as bread packaging and compared with synthetic and open packaging for shelf-life analysis. In observation, it was found that it has increased the shelf life of packed bread and reduced the growth of food-borne microbes in bread. This fabricated antimicrobial biocomposite is an eco-friendly packaging film that may reduce the food wastage and environmental impact of packaging materials by utilizing agricultural waste.
... The optimal pH of functional food sorbets helps maintain their stability, assists with cost-effective production methods and avoids causing potential health problems. The pH of sorbets is dependent on the overall composition of the fruit juice, and to extend the shelf life as well as increase the integrity of the added ingredient, changing the pH environment is one of many different approaches used to maintain the stability of the added bioactive [39]. For instance, green tea constituents such as tea polyphenols and amino acids present a more comprehensive stability range in different pH environments in which they are highly pH-dependent (pH 3-6), especially favoring acidic conditions [40]. ...
Article
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Functional foods and beverages are becoming one of the leading food products on the global market today. This is predominately due to the consumer, industry and research-related interests in the use of food-derived products for the management of several chronic conditions. The diversity of currently available functional food products also provides an opportunity for the use of fruit-based sorbets as a carrier of functional ingredients. Therefore, the aim of this literature review is to explore the use of sorbets as a functional food product, which is one commercial method that can be utilized to provide health benefits, extend the shelf life of foods, and preserve nutrients and improve taste. Firstly, we provide an overview of sorbets as a functional food matrix, their development and implications for the absorption of functional ingredients in humans. We discuss the developmental considerations of functional foods, such as the technical conditions and physicochemical and organoleptic properties through which functional foods can provide beneficial health effects. These include product stability, metabolism of the functional food ingredient, its interactions with the food matrix and limitations related to its production. There is a paucity of clinical data that investigate the long-term health effects of products claiming additional functional benefits. Given the extensive potential benefits of functional bioactive food compounds and their heavy prevalence in the market, extensive research and further regulation is needed to ensure health recommendations for large populations in longitudinal clinical studies warranting any functional claim.
... Nhìn chung, lượng vi sinh vật hiếu khí tổng số của purée ở các nghiệm thức có bổ sung kali sorbate (E4, E5 và E6) thấp hơn so với các nghiệm thức còn lại ở cùng thời gian bảo quản. Điều này là do kali sorbate tác dụng ức chế đối với hầu hết các nấm mốc, nấm men và nhiều loài vi khuẩn hiếu khí trong thực phẩm (Tompkin et al., 1974;Gliemmo et al., 2010;Singh et al., 2016). ...
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Nghiên cứu này khảo sát các điều kiện bảo quản đối với puree bí đỏ ở nhiệt độ lạnh nhằm duy trì chất lượng, đảm bảo an toàn và kéo dài thời gian bảo quản. Đường và kali sorbate được bổ sung ở các nồng độ khác nhau và theo dõi các biến đổi về chất lượng hóa lý và vi sinh vật của puree khi bảo quản ở 10±2oC. Kết quả cho thấy, puree bí đỏ được bảo quản ở điều kiện đối chứng (không bổ sung phụ gia) có hạn sử dụng là 3 ngày. Puree bổ sung 10% đường và 0,05% kali sorbate có thể giúp kéo dài thời gian bảo quản của puree bí đỏ đến ngày thứ 9. Sự sai biệt màu sắc tổng thể, a* và b* của puree bí đỏ có xu hướng tăng khi kéo dài thời gian bảo quản trong khi L*, oBrix và aw có xu hướng giảm. Nhìn chung, hàm lượng carotenoid của puree không thay đổi đáng kể sau quá trình bảo quản. Nghiên cứu cũng cho thấy sự phát triển của vi sinh vật là nguyên nhân chính dẫn đến hư hỏng và ảnh hưởng đến hạn sử dụng của puree bí đỏ.
... The improved microbial reduction for cherry tomatoes when US-FC/ PAA was combined with UV-C irradiation constitutes hurdle technology and was likely caused by the simultaneous actions of disinfectants exerting different antibacterial mechanisms (Wang et al., 2022b;Singh and Shalini, 2016), including low-frequency US, which causes damage to the cell membrane. In an aqueous solution, US waves can induce compression and expansion; positive pressure can push molecules together during compression, while expansion generates cavities due to negative pressure (Yu et al., 2020). ...
Article
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Microbial contamination is the most significant risk associated with consuming minimally processed fresh food products. The processing time of ultrasound (US)-assisted washing generally exceeds 5 min. To reduce the processing time, yet maintain or improve the efficacy of US-free chlorine (FC, 10 ppm) or -peracetic acid (PAA, 80 ppm) (US-FC/PAA), we simultaneously applied ultraviolet C (UV–C) irradiation. Compared with US-FC/PAA (5 min), US-FC/PAA-UV (3 min; 1.71 kJ/m²) treatment of cherry tomato further reduced food-borne pathogens (E. coli O157:H7, non-O157 E. coli, and Salmonella Typhimurium) by 0.45–0.73 log CFU/g and naturally present microbes (aerobic mesophiles, psychrophiles, molds, and yeasts) by 0.28–0.50 log CFU/g. For fresh-cut lettuce, the efficacy achieved using US-FC/PAA-UV did not exceed that using US-FC/PAA, indicating that US-FC/PAA-UV is more effective in reducing contamination on produce with a smoother surface, e.g., cherry tomato. Sensory qualities (color, odor, crispness, and firmness), antioxidant activity, and phenolic, ascorbic acid, lycopene, and chlorophyll content were not affected by any of the treatments. These results suggest that the simultaneous application of US-FC/PAA and UV-C is an effective alternative to US-FC/PAA washing that reduces processing time and thus improves productivity.
... The quality of food always decreases during any processing, and the decreasing rate depends on the processing intensity. Thus, hurdle technology has been developed in the food industry, which combines several mild processing technologies to achieve the target process instead of one single processing with high intensity [5]. Theoretically, drying can was taken out for 1.5 h soused processing within commercial liquid synthesis flavoring (Niulege, Chengdu, China). ...
Article
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The objective of this study was to investigate the effects of microwave pasteurization on the quality and shelf-life of low-sodium and intermediate-moisture Pacific saury. Microwave pasteurization was used to process low-sodium (1.07% ± 0.06%) and intermediate-moisture saury (moisture content 30% ± 2%, water activity 0.810 ± 0.010) to produce high-quality ready-to-eat food stored at room temperature. Retort pasteurization with the same thermal processing level of F90 = 10 min was used for comparison. Results showed that microwave pasteurization had significantly (p < 0.001) shorter processing times (9.23 ± 0.19 min) compared with traditional retort pasteurization (17.43 ± 0.32 min). The cook value (C) and thiobarbituric acid (TBARS) content of microwave-pasteurized saury were significantly lower than that of retort-pasteurized saury (p < 0.05). With more microbial inactivation, microwave pasteurization brought better overall texture than retort processing. After 7 days of storage at 37 °C, the total plate count (TPC) and TBARS of microwave pasteurized saury still met the edible standard, while the TPC of retort pasteurized saury no longer did. These results showed that the combined processing of microwave pasteurization and mild drying (Aw < 0.85) could produce high-quality ready-to-eat saury products. These results indicate a new methodology for producing high-quality products stored at room temperature.
... Frontiers in Sustainable Food Systems 09 frontiersin.org temperature, pH, salt, and UV stress to prolong their shelf life, preserve their nutritional value, and prevent microbial spoilage (Singh and Shalini, 2016;Amit et al., 2017). We may argue that contamination of food products by antimicrobial-resistant strains in FPEs and laterally consumed by consumers may be more difficult to treat in clinical settings. ...
Article
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Listeria species are exposed to various stressors throughout the food chain, which are crucial for microbe mitigation strategy in the food industry. However, the survival capabilities and development of antimicrobial resistance by Listeria spp. under different food processing environments (FPEs) stressors are not yet well understood. Hence, this study aims to determine the difference in survivability and antimicrobial susceptibility of L. monocytogenes (Lm) and other Listeria species (non-Lm) strains exposed to different FPEs stressors, including heat, acidic and alkaline pH, UV irradiation, and osmotic stress. For this, a collection of 11 Lm and 10 non-Lm strains were used to conduct experiments. This study showed that Lm strains were relatively more tolerant to environmental stresses than non-Lm strains (p > 0.05). Additionally, the evaluation of stress-induced resistance toward antimicrobials showed that anaerobic incubation, after exposition to environmental stresses, rendered Lm and non-Lm more resistant to antimicrobial agents than aerobic incubation. Furthermore, the study observed that different stressors induced an increase in minimum inhibitory concentrations (MICs) of certain antimicrobials. Specifically, heat stress persuaded an increase in MICs of tetracycline under aerobic incubation, and gentamicin and ciprofloxacin under anaerobic incubation. Acidic/alkaline pH induced an increase in MICs of gentamicin, ciprofloxacin, and trimethoprim-sulfamethoxazole, especially under anaerobic incubation. However, UV stress induced increase in MICs of tetracycline and trimethoprim-sulfamethoxazole under aerobic incubation and gentamicin, ciprofloxacin, and trimethoprim-sulfamethoxazole under anaerobic incubation. Additionally, osmotic stress induced an increase in MICs of tetracycline and ampicillin under aerobic incubation and gentamicin, tetracycline, and trimethoprim-sulfamethoxazole under anaerobic incubation. Collectively, this study highlights that stress tolerance may contribute to the predominance of Listeria species among FPEs and induce the development of antimicrobial resistance even without antibiotic selection pressure. The findings of this study may guide updated strategies to mitigate Listeria species in the food industry.
... Hurdle technology involves combining multiple preservative factors to achieve maximum microbial lethality while minimizing any negative impact on the quality of the product. Examples of these preservative factors include heating, acidification, and the addition of preservatives, among others [138,139]. The hurdle technology was used to both kill microbes and improve the quality of soft persimmon juice during storage. ...
Article
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Thermosonication (TS) has been identified as a smart remedy for the shortcomings of heat treatment, which typically requires prolonged exposure to high temperatures. This technique combines moderate heat treatment with acoustic energy to eliminate harmful microorganisms and enzymes in food products. Unlike conventional heat treatment, thermosonication utilizes short holding times, allowing for the preservation of food products’ phytochemical compounds and sensory characteristics. The benefits and challenges of this emerging technology, such as equipment cost, limited availability of data, inconsistent results, high energy consumption, and scale-up challenges, have been assessed, and the design process for using ultrasound in combination with mild thermal treatment has been discussed. TS has proven to be a promising technique for eliminating microorganisms and enzymes without compromising the nutritional or sensory quality of food products. Utilizing natural antimicrobial agents such as ascorbic acid, Nisin, and ε-polylysine (ε-PL) in combination with thermosonication is a promising approach to enhancing the safety and shelf life of food products. Further research is required to enhance the utilization of natural antimicrobial agents and to acquire a more comprehensive comprehension of their impact on the safety and quality of food products.
... Food manufacturers employ many multimethods worldwide to ensure their products' safety, including heat pasteurization, high-pressure processing (HPP), microwave irradiation, chemical sanitizers, and natural additives/antioxidants, each with their drawbacks [52][53][54]. Thermal pasteurization results in the food being cooked and therefore unsuitable for fresh food items. At the same time, high-pressure treatment has deteriorating effects on the nutritional quality and appearance of foods such as fresh produce and meat [53,55,56]. ...
Article
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Research and development on innovative packaging materials have advanced significantly to safeguard packaged food against microbial contamination and oxidation. Active packaging has recently developed as a practical approach to reducing oxidation and microbiological growth in packaged goods, extending their shelf life and protecting consumers from potential harm. Active food packaging includes O2, CO2 scavengers, moisture absorbers, U. V. barriers, and antimicrobial agents. Various antimicrobial agents, such as nitrates and benzoic acids, are incorporated into food packaging formulations. Consumers demand natural antimicrobials over chemical/synthetic ones, such as bacteriocins, bacteriophages, and essential oils. Bacteriophages (viruses) have emerged as a feasible option for decontaminating and eliminating infections from food sources. Most importantly, these viruses can target specific foodborne pathogens without harming helpful bacteria or infecting humans and livestock. Fortifying bacteriophages into food packaging films will not only kill specific food microorganisms but has also evolved as a new weapon to combat antimicrobial-resistant (AMR) issues. The present review summarises recent developments in active antimicrobial packaging focused particularly on bacteriophage food packaging applications and advantages, drawbacks, and future trends for active food packaging.
... The study of fish spoilage, the monitoring and the determination of its shelf-life during various commercialized storage conditions and the development of targeted strategies to control the spoilage course are of great interest to extend its shelf-life and thus, ensure its quality and increase its added value [7]. Apart from the effort to achieve a longer shelf-life, various treatments based on the hurdle technology concept [8][9][10] lead to the creation of different kinds of products which offer a variety of added-value seafood products. ...
Article
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The aim of the present work was to evaluate the effect of various hurdles such as a w and pH as well as the storage atmosphere on the microbiological and sensory changes of minimally processed (lightly brined or marinated with acetic or citric acid) European sea bass (Dicentrarchus labrax) fillets. The results indicated that the shelf-life of brined fillets stored aerobically was 6 d while that of vacuum and MAP-stored was 12 d, since a reduced growth rate of spoilage bacteria was recorded. The physicochemical characteristics such as a w and water phase salt (WPS) were not considerably changed, while the oxygen levels into the packages ensure the microbiological safety of the product. The fillets marinated with acetic acid exhibited a longer shelf-life at 30 and 40 d under aerobic and reduced oxygen conditions, respectively, while the products marinated with citric acid were at 25 and 35 d respectively. A low pH resulted in reduced or even limited microbial levels, especially for the fillets marinated with acetic acid; something that ensures microbiological safety as well. The low or limited microbial levels in conjugation with the sensory attributes indicated that spoilage may be due to other mechanisms such as autolysis rather than microbial activity. Overall, the present work highlights the potential for further research and development of minimally processed, microbiologically safe and stable with extended shelf-life value added seafood to satisfy the corresponding consumer demands.
... Food manufacturers employ many multi-methods worldwide to ensure their products' safety, including heat pasteurization, high-pressure processing (HPP), microwave irradiation, chemical sanitizers, and natural additives/antioxidants, each with their drawbacks [52][53][54]. Thermal pasteurization results in the food being cooked and, therefore, unsuitable for fresh food items. At the same time, high-pressure treatment has deteriorating effects on the nutritional quality and appearance of foods such as fresh produce and meat [53,55,56]. ...
Preprint
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Research and development on innovative packaging materials have advanced significantly to safeguard packaged food against microbial contamination and oxidation. To combat demanding issues, active packaging has evolved as a viable method for minimizing oxidation/microbial growth in packaged goods, extending their shelf life, and ensuring the consumer's safety. Active food packaging includes O2, CO2 scavengers, moisture absorbers, U.V. barriers, and carriers of antioxidant and antimicrobial agents. Various antimicrobial agents are carried and/or incorporated into food packaging formulations. Consumers demand natural antimicrobials over chemical/synthetic ones, such as bacteriocins, bacteriophages, and essential oils. Bacteriophages (viruses) have emerged as a feasible option for decontaminating and eliminating infections from food sources. These viruses can target specific food-borne pathogens without impairing beneficial bacteria and, most critically, without causing disease in humans or animals. Fortifying bacteriophages into food packaging films will not only kill specific food microorganisms but has evolved as a new weapon to combat antimicrobial-resistant (AMR) issues. The present review summarises recent developments in active antimicrobial packaging focused particularly on bacteriophage-food packaging applications and advantages, drawbacks, and future trends for active food packaging.
... Nevertheless, nowadays, the intelligent application of the hurdle concept is highly prevalent in the food industry, since a deeper understanding of the intrinsic and extrinsic food factors has been established. In the last decades, the influence of temperature, water activity (a w ), pH, redox potential (Eh) and competitive microflora, along with their interactions on pathogenic microbial behavior and physiology in food, have been widely studied, amplifying the intelligent use of hurdles in food manufacturing [5]. ...
Article
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The application of several sublethal stresses in hurdle technology can exert microbial stress resistance, which, in turn, might enable foodborne pathogens to overcome other types of lethal stresses, such as the gastrointestinal barriers. The present study evaluated the survival of Salmonella Typhimurium and Listeria monocytogenes during simulated digestion, following exposure to combinations of water activity (aw), pH and storage temperature stresses. The results revealed that both pathogens survived their passage through the simulated gastrointestinal tract (GIT) with their previous habituation to certain hurdle combinations inducing stress tolerance. More specifically, the habituation to a low temperature or to a high pH resulted in the increased stress tolerance of Salmonella, while for Listeria, the cells appeared stress tolerant after exposure to a high temperature or to a low pH. Nonetheless, both pathogens expressed increased sensitivity after habituation to growth-limiting hurdle combinations. The survival of stress-tolerant pathogenic cells in the human GIT poses major public health issues, since it can lead to host infection. Consequently, further research is required to obtain a deeper understanding of the adaptive stress responses of foodborne bacteria after exposure to combinations of sublethal hurdles to improve the existing food safety systems.
... Misalkan, Listeria monocytogenes yang dapat bertahan hingga pengolahan sosis kering meskipun pada kondisi pH rendah, garam, dan nitrit, serta dapat menyebabkan penyakit bawaan pangan (Fontana et al., 2015). Untuk mencegah atau menghambat baik mikroorganisme pembusuk maupun patogen dapat dilakukan dengan berbagai cara, di antaranya adalah dengan menurunkan aktivitas air (Aw), menurunkan pH, penambahan bahan pengawet alami atau sintetik, penggunaan suhu rendah maupun dengan pembekuan (Singh & Shalini, 2016). Pada bab ini, akan dibahas pengawetan bahan pangan dengan menggunakan suhu rendah dan pembekuan. ...
Book
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Pengawasan mutu merupakan salah satu langkah untuk menjaga kualitas suatu produk makanan/pangan baik industri maupun hasil ternak. Buku ini ditulis secara bersinergi yang bertujuan untuk mempermudah mahasiswa dan praktisi yang ingin mempelajari tentang sejarah pengawasan mutu, bagaimana mutu bahan pangan yang baik, dengan memperhatikan kerusakan dan penurunan mutu pangan. Mutu pangan dapat dikendalikan dan diawasi dengan berbagai program pengendalian mutu dan keamanan pangan. Selain itu juga dibahas tentang pengetahuan kulit ternak, proses pengawetan dengan permainan suhu, kimia aditif, fermentasi bahkan dengan pengasapan. Buku yang ditulis secara kolaboratif oleh berbagai penulis dari berbagai institusi sebagai perwujudan penegakan tri dharma perguruan tinggi.
... Foodborne illness is believed to represent a serious public health hazard worldwide, with 420,000 fatalities happening each year (2). One potential strategy for lowering foodborne infections is the development of efficient preservation systems capable of eradicating microbial contamination of food (3). Antibiotic resistance in microorganisms has arisen because of widespread usage of accustomed antibiotics, posing a threat to public health (4). ...
Article
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For controlling pathogenic bacteria using nano-polymer composites with essential oils, the formulation of chitosan/alginate nanocomposites (CS/ALG NCs) loaded with thyme oil, garlic oil, and thyme/garlic oil was investigated. Oils were encapsulated in CS/ALG NCs through oil-in-water emulsification and ionic gelation. The CS/ALG NCs loaded with oils of garlic, thyme, and garlic-thyme complex had mean diameters of 143.8, 173.9, and 203.4 nm, respectively. They had spherical, smooth surfaces, and zeta potential of +28.4 mV for thyme-garlic-loaded CS/ALG NCs. The bactericidal efficacy of loaded NCs with mixed oils out-performed individual loaded oils and ampicillin, against foodborne pathogens. Staphylococcus aureus was the most susceptible (with 28.7 mm inhibition zone and 12.5 µg·mL −1 bactericidal concentration), whereas Escherichia coli was the most resistant (17.5 µg·mL −1 bactericidal concentration). Scanning electron microscopy images of bacteria treated with NCs revealed strong disruptive effects on S. aureus and Aeromonas hydrophila cells; treated cells were totally exploded or lysed within 8 h. These environmentally friendly nanosystems might be a viable alternative to synthetic preservatives and be of interest in terms of health and food safety.
... The fact that acquisition of acid resistance tends to cause cross-resistance to heat in E. coli is troublesome, given the fact that this species harbors many foodborne pathovars (55) and that heat and acid are the predominant stresses used in food preservation (56). Especially in the upcoming minimal-processing regimens that aim to better retain food sensorial properties by depending on the synergistic combination of mild stresses, the use of acid as an extra hurdle to be able to lower heat exposure is popular (57). In this context, pathogens readily acquiring cross-resistance against acid and heat pose a liability. ...
Article
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Since acidic environments often serve as an important line of defense against bacterial pathogens, it is important to fully understand how the latter manage to mount and evolve acid resistance mechanisms. Escherichia coli, a species harboring many pathovars, is typically equipped with the acid fitness island (AFI), a genomic region encoding the GadE master regulator together with several GadE-controlled functions to counter acid stress. This study reveals that gadE and consequently AFI functions are heterogeneously expressed even in the absence of any prior acid stress, thereby preemptively creating acid-resistant subpopulations within a clonal E. coli population. Directed evolution efforts selecting for modulated gadE expression confirm that a gain-of-function mutation in the EvgS sensor kinase can constitutively upregulate gadE expression and concomitant acid resistance. However, we reveal that such upregulation of EvgS also causes cross-resistance to heat stress because of SafA-mediated cross-activation of the PhoPQ regulon. Surprisingly, loss of function of the serC gene (encoding phosphoserine/phosphohydroxythreonine aminotransferase) can also significantly upregulate gadE expression, acid resistance, and heat cross-resistance, although via a currently cryptic mechanism. As such, our data reveal a noisy expression of gadE in E. coli that is functional for the survival of sudden acid stress and that can readily be genetically tuned. IMPORTANCE Acidic environments constitute one of the most important stresses for enteric bacteria and can be encountered in both natural (e.g., host gastrointestinal tract) and manmade (e.g., food processing) environments. The enteric species Escherichia coli harbors many pathovars and is well known for its ability to cope with acid stress. In this study, we uncover that E. coli's acid fitness island (AFI), a genomic region that encodes important functions to deal with acid stress, is by default expressed in a heterogeneous manner. In fact, using microfluidics-based single-cell approaches, we further demonstrate that this heterogeneity preemptively creates a clonal subpopulation that is much better equipped to survive a sudden acid shock. In addition, we reveal that environments with recurring acid stress can readily select for mutants displaying a higher fraction of AFI-expressing cells. These new insights are important to properly understand and anticipate the survival characteristics of E. coli.
... The combination of more than one approach, also known as hurdle technology, can be used to the obtain desired results with better efficiency than other methods [103,104]. ...
Article
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Maintaining the overall quality and shelf life of plant-based food and beverages is particularly important yet challenging to the food industry. Demand for natural preservation techniques has increased with the rising concerns over food safety and consumer awareness, e.g., health consciousness and food trends such as veganism and the demand for clean, labelled foods. Thus, a technique such as biopreservation has the potential to enhance food safety while fostering the quality, originality and naturalness of food. The application of probiotic microorganisms to foods and beverages provides various health benefits in addition to improved shelf life, stability and microbial safety of the food. The provision of probiotics is known to deliver various health benefits for the host’s gut health. Therefore, this review aims to investigate the importance of biopreservation and the role of probiotics in the food industry. An attempt was made to explore the various possibilities of shelf-life enhancement through the use of probiotic microorganisms as biopreservatives. Noticeable improvements in the shelf life of plant-based foods and beverages were observed due to the antimicrobial effects exerted by probiotics and potential probiotic strains which make them useful alternatives to artificially synthesized chemical preservatives.
... The other non-thermal processing techniques for beverages such as ozone treatment, use of antimicrobial metabolites, fermentation, and combinations of the technologies mentioned so forth, also commonly described as hurdle technologies, are being actively researched, and interested readers are directed toward other excellent reviews, books, and studies (Lacroix 2010;Badwaik et al. 2015;Singh and Shalini 2016;Brodowska et al. 2018). ...
Chapter
The beverage industry is one of the largest food processing sectors and the elevated growth of this industry is driven by consumer awareness toward eating nutritional and healthy diets. Consuming fresh beverages is universally recommended, however, fresh fruits and vegetable juices or their blends are prone to contamination by pathogenic- and spoilage-causing microbes. Consumption of such unsound beverages has led to multiple instances of food-borne disease outbreaks in the past. To ensure the delivery of microbiologically safe juices, alongside ensuring nutritional intactness and freshness, the beverage industry employs a gamut of technologies to decontaminate juices following national or international norms and practices, eg., conventional technologies like pasteurization and sterilization (thermal technologies). However, these treatment measures are known to drastically diminish nutrients and the flavor profile of juices. Additionally, consumer awareness toward minimally-treated products has led the industry to seek alternative technologies to improve preservation practices for adequate microbial safety, while maintaining freshness and flavor. The current chapter deals with the state-of-the-art practices in decontamination of beverage products, including high-pressure, pulsed-electric, pulsed-light, ultrasound and cold-plasma, and offers new sets of opportunities for both academia and industry.KeywordsFruit juiceBeverageThermal technologiesHigh pressureMinimally processed
... In recent years, due to the significant changes in consumer perception, specifically toward (i) minimally processed foods, (ii) functional foods and (iii) less packaged foods, there has been a growing interest in the application of hurdle technology in the food processing industry. Presently, hurdle technology aims to provide a maximum lethality against the targeted foodborne pathogens (Singh and Shalini 2016), an extension of the shelf-life and at the same time preserve the nutritional and sensory quality of the food product. It is important to emphasize that the selection of hurdles and the final application of this technology will depend not only on the type of food product but also on the physiological and ecological characteristics of the targeted foodborne pathogen. ...
Article
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Listeria monocytogenes, a causative agent of listeriosis, is a major foodborne pathogen. Among pathogens, L. monocytogenes stands out for its unique ecological and physiological characteristics. This distinct lifestyle of L. monocytogenes has a significant impact on food safety and public health, mainly through the ability of this pathogen to multiply at refrigeration temperature and to persist in the food processing environment. Due to a combination of these characteristics and emerging trends in consumer preference for ready-to-eat and minimally processed food, there is a need to develop effective and sustainable approaches to control contamination of food products with L. monocytogenes. Implementation of an efficient and reliable control strategy for L. monocytogenes must first address the problem of cross-contamination. Besides the preventive control strategies, cross-contamination may be addressed with the introduction of emerging post packaging non-thermal or thermal hurdles that can ensure delivery of a listericidal step in a packed product without interfering with the organoleptic characteristics of a food product. This review aims to present the most relevant findings underlying the distinct lifestyle of L. monocytogenes and its impact on food safety. We also discuss emerging food decontamination technologies that can be used to better control L. monocytogenes.
... In many instances, microorganisms are exposed to mild stress levels that only reduce growth without causing loss of viability [90]. Due to the demand for minimally processed foods that preserve the natural freshness and nutritional quality, many foods are processed by the use of mild processing technologies that apply a combination of many sub-lethal stress treatments [91]. Despite the benefits of such approaches, exposure to sub-lethal stresses can induce the development of adaptive stress tolerance responses that enhance the survival of pathogens when exposed to subsequent lethal stress along the food value chain [15]. ...
Article
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Adaptive stress tolerance responses are the driving force behind the survival ability of Listeria monocytogenes in different environmental niches, within foods, and ultimately, the ability to cause human infections. Although the bacterial stress adaptive responses are primarily a necessity for survival in foods and the environment, some aspects of the stress responses are linked to bacterial pathogenesis. Food stress-induced adaptive tolerance responses to acid and osmotic stresses can protect the pathogen against similar stresses in the gastrointestinal tract (GIT) and, thus, directly aid its virulence potential. Moreover, once in the GIT, the reprogramming of gene expression from the stress survival-related genes to virulence-related genes allows L. monocytogenes to switch from an avirulent to a virulent state. This transition is controlled by two overlapping and interlinked transcriptional networks for general stress response (regulated by Sigma factor B, (SigB)) and virulence (regulated by the positive regulatory factor A (PrfA)). This review explores the current knowledge on the molecular basis of the connection between stress tolerance responses and the pathogenesis of L. monocytogenes. The review gives a detailed background on the currently known mechanisms of pathogenesis and stress adaptation. Furthermore, the paper looks at the current literature and theories on the overlaps and connections between the regulatory networks for SigB and PrfA.
Article
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Hurdle technology combines several preservation methods to secure the quality of foods by eliminating or controlling the growth of pathogens, making them last longer and, most importantly, safer for consumption. The hurdle approaches used for this Pekasam is microbially derived hurdle and physico-chemical hurdles. Inoculation of starter cultures with amine oxidase (AO) activity like lactic acid bacteria (LAB) in Pekasam is proven to reduce the accumulation of harmful biogenic amines, especially histamine, for up to 59.9%. This review also involves controlling the water activity and pH of Pekasam to a state where it inhibits the growth of microbes. This can be done by adding natural, cheap, and easy to find ingredients like lime juice (Citrus aurantifolia) to the basic Pekasam recipe. The presence of organic acids in the lime juice act as acidulants; it provides a low pH environment for microbes to retard their growth and therefore reduce the total plate count (TPC) whilst enhancing the flavour of Pekasam. However, in a long- ripened Pekasam, only the water activity hurdle is strengthened with time. Hence, a proper amount of salt is needed to sustain and maintain the water activity level below 0.94. The use of affordable herbs and spices with antimicrobial properties such as garlic, ginger and onion can prevent the proliferation of some pathogenic microbes, commonly found in Pekasam; thus, this helps in increasing the stability of the product. This review aims to outline the application of hurdle technology on fermented freshwater fish quality and shelf life. It focuses on recent accessible applications when combined, providing affordable food which helps those underprivileged people, especially during flash floods and other disruptive calamities such as the COVID-19 pandemic.
Article
Listeria monocytogenes is a critical foodborne pathogen that causes listeriosis and threatens public health. This pathogenic microorganism forms a transmission cycle in nature, food industry, and humans, expanding the areas of contamination among them and influencing food safety. L. monocytogenes forms biofilms to protect itself and promotes survival through stress responses to the various stresses (e.g., temperature, pH, and antimicrobial agents) that may be inflicted during food processing. Biofilms and mechanisms of resistance to hostile external or general stresses allow L. monocytogenes to survive despite a variety of efforts to ensure food safety. The current review article focuses on biofilm formation, resistance mechanisms through biofilms, and external specific or general stress responses of L. monocytogenes to help understand the unexpected survival rates of this bacterium; it also proposes the use of obstacle technology to effectively cope with it in the food industry.
Article
Aims: The purpose of this study was to determine whether plant-associated bacteria (PAB) can reduce Salmonella enterica colonization and infection of alfalfa sprouts to reduce the risk of foodborne illness. Methods: We isolated plant associated bacteria from alfalfa seeds and sprouts. Monoclonal isolates of the bacteria were obtained and tested for their ability to inhibit Salmonella Typhimurium growth in alfalfa sprouts over 6-days. Genome sequencing and annotation was used to construct draft genomes of the bacteria isolated in this study using Illumina sequencing platform. Results: We observed that a cocktail of five PAB could reduce Salmonella growth in alfalfa sprouts from ∼108 CFU g-1 to ∼105 CFU g-1, demonstrating a protective role. Genome sequencing revealed that these bacteria were members of the Pseudomonas, Pantoea, and Priestia genus, and did not possess genes that were pathogenic to plants or animals. Conclusions: This work demonstrates that PAB can be utilized to reduce pathogen levels in fresh produce which may be synergistic with other technologies to improve the safety of sprouts and other fresh produce.
Chapter
Food analysis plays a vital role in evaluating food materials’ quality and safety meant for human consumption. Globally, it is advised to follow standardized test protocols and methods for assessing various food components and parameters. Most analytical methods are regularly updated with the advent of technology for precise and accurate measurement. In the past two decades, there has been immense advancement with respect to instrumentation, primarily due to electronics and material science. Getting a food material tested and certified in an approved food laboratory is mandatory to comply with the regulation. However, nowadays, technologically advanced consumers are interested in testing their food for its quality and safety through hand-held devices and smartphones. In the wake of these advancements, researchers are exploring new food testing methods to supplement the demand of consumer and regulatory standards. This work discusses the research trends reported in the past five years towards food testing. The advantages and disadvantages of the new methods are discussed along with future directions.KeywordsFood analysisFood safetyFood qualityHuman healthFood regulations
Article
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Introduction: The presence of meat-borne pathogens entering the home remains a concern for consumers, despite advances made in improving antimicrobial interventions and systems within the processing line. Naturally antibacterial food ingredients including citrus juice and essential oils have been proven to inhibit the proliferation of microbial growth with varying success. Aims: This study aims to investigate the antimicrobial and sensory effects of mixtures of essential oils, fruit juices and herbs at established Minimum Inhibitory Concentrations (MICs) for their biopreservative effect on general microbiota of chicken and against chicken challenged with selected pathogenic/surrogate microorganisms. Materials and methods: Three marinade compositions were designed for use on chicken meat; lemon juice, thyme oil and black pepper (M1), lime juice, lemongrass oil and chilli paste (M2), and olive oil, oregano oil, basil oil and garlic paste (M3). These marinades were assessed for antibacterial effects against Salmonella enterica, Campylobacter jejuni and Listeria innocua on marinaded chicken drumsticks stored in aerobic conditions at 4 °C. Consumer tasting sessions were also conducted with a small focus group using selected final marinades. Results: M1 and M2 were effective at significantly reducing initial pathogen carriage from 6 Log CFU/g to 2 Log CFU/g on refrigerated chicken meat as well as increasing the shelf-life of the product during cold-storage from 2 days to 7 days. However, consumer studies indicate that the flavours these marinades impart to treated products can be strong. Conclusion: These findings indicate that these designed marinades have shown excellent potential to improve food safety as well as shelf-life for the consumer, particularly in settings where food safety is often compromised such as barbecuing or in care settings. However, further recipe optimisation is required to make these marinades acceptable to consumers.
Chapter
The reduction dietary intake of sodium is considered one of the greatest demands worldwide in order to decrease the risk of hypertension and cardiovascular diseases, responsible for a high mortality rate worldwide. The main source of sodium in the diet comes from sodium chloride (NaCl), the edible salt most commonly used in foods. Sodium chloride has many technological functions which include preservative effects resulting from the reduction of water activity, improving functional properties of many classes of proteins and the excellent sensory properties, especially its salty taste. Solutions to replace and/or reduce NaCl content in foods consider the use of substitute chloride salts such as KCl, CaCl2, MgCl2, natural flavor enhancers, and new process technologies in combination with other barriers to meet physicochemical, microbiological, sensory stability. These topics will be discussed in detail throughout this chapter.
Chapter
A hurdle technology-based approach for the reduction in immunogenicity of shrimp major allergen, tropomyosin was investigated by combining electron beam irradiation at 5 kGy and boiling, autoclaving, trypsin and chymotrypsin treatments along with peeled raw shrimp as control. Shrimp extracts were prepared from the irradiated sample and evaluated SDS PAGE profile, IgE binding ability and immunogenicity of tropomyosin using pooled sera of shrimp sensitive individuals. Electron beam irradiation resulted in significant (p < 0.05) decrease in the IgE activity in the case of all treatments. The SDS PAGE analysis showed the presence of tropomyosin in all the treatments except autoclaving in combination with or without electron beam irradiation. A pronounced reduction in allergenicity was observed in the treatment of autoclaving in combination with electron beam irradiation. The combined application of autoclaving and electron beam irradiation can be utilized for the preparation of hypoallergic shrimp.
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Consumers have been consistently concerned about possible adverse health effects from the presence of chemical additives in their foods. As a result, consumers are drawn to natural and fresher foods with no chemical preservatives added. This perception has stimulated research interest in finding natural but effective preservatives. Use of natural or controlled microbiota or antimicrobials as a way of preserving food and extending its shelf life is termed as biopreservation. The biopreservation of food, especially utilizing lactic acid bacteria (LAB) that are inhibitory to food spoilage microbes, has been practiced since early ages. Beneficial bacteria or the fermentation products produced by these bacteria are used in biopreservation to control spoilage and render pathogens inactive in food. Followed by bacteriocin, poly- l -lysine and its derivatives have gained recent attention in food sector and used as preservative in diverse food products. They are watersoluble, edible, and nontoxic with respect to the environment and humans. In general, cationic polypeptides (such as –PLL) have been used as auxiliary agents in drug delivery systems. PL is rich in cations, which has a strong electrostatic force with anionic substance and good penetration to biofilms. So it can be used as the carrier of drugs. It improves drug efficacy when polymerized with carbamoyl purine, a drug for leukemia, tumor. In bioscience researches, it is a good fusogenic agent used in electrofusion method. This review reveals the biopreservation principles of poly- l- lysine and its potential applications in nutraceuticals, which would suggest the possible utilization of polylysine as an effective, biocompatible food preservation.
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Sugarcane juice was subjected following treatments viz. pasteurization at 80ºC for 10 min + chemical treatments (KMS @ 150 ppm and citric acid @ 0.05%); pasteurization at 80ºC for 10 min + chemical treatments (KMS @ 150 ppm and citric acid @ 0.05%) + sterilization at 80ºC for 20 min. All the samples were packed in glass bottles, polyethylene Tetrapthelate (PET) bottles and low density polyethylene pouches (LDPE) and then irradiated at 0.25, 0.5 and 1.0 kGy and stored for 90 days at room and low temperature. Non-irradiated samples were taken as control. On treatment moisture content, ascorbic acid, viable bacterial count and viable yeast and mold count were decreased significantly (P > 0.05) where as no significant effect was observed on reducing and total sugars in cane juice. Among the three packaging material used glass and PET was found to be at par in increasing the shelf life of sugarcane juice in comparison to LDPE pouches. On storage, ascorbic acid and total sugars were decreased significantly (P > 0.05). Moisture content, viable bacterial count and viable yeast mold count were increased on storage. Irradiation and packaging material statistically showed no significant differences on organoleptic properties of juice but storage showed changes in sensory scores. Among all the treatments pasteurization at 80ºC for 10 min + chemical treatments (KMS @ 150 ppm and citric acid @ 0.05%) + sterilization at 80ºC for 20 min was found to be best in maintain the shelf life of juice up to 60 days at room temperature and 90 days at low temperature with 1.0 kGy irradiation doses. Among glass bottles, PET bottles and LDPE pouches, glass and PET were found to be best in maintaining the quality of juice.
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Hurdle technology employs the intelligent combination of different preservation factors to achieve mild but reliable preservation effects. Fresh coconut gratings treated with different combinations of hurdles such as acidulants, humectants, preservatives, antioxidants, a mild heat treatment and packaging were evaluated for changes in physico-chemical and sensory properties. It is possible to preserve the grating for four weeks in laminated polythene packages at 5°C in combination with 3% sodium chloride, 0.3% citric acid, 0.009% sodium citrate, 0.02% butvlated hydroxvanisole.
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Cauliflower (Brassica oleracea var. 'Botrytis') was preserved by low-cost and low-energy processing technology (hurdle technology) involving different concentrations and combinations of salt (5, 10 and 15%), potassium metabisulphite (KMS) (0.2%) and citric acid (CA) (1.0%) after blanching. Physico-chemical, sensory and microbial observations were recorded on the preparation day and subsequently after 15, 45, 90 and 180 days of storage. Preserved cauliflower after 90 and 180 days of storage was reconstituted in running water for half an hour and evaluated for the preparation of pickle and pakora. The cauliflower samples steeped in 10 and 15% salt solution containing 0.2% KMS were rated best among treatments during the entire period of storage. The cost of production of steeped cauliflower in 10 and 15% salt solution (along with KMS 0.2% and CA 1.0%) were worked out to Rs. 4.03 and 4.15 per jar, respectively. Sensory profile of steeped cauliflower after reconstitution and also on preparation of pickle and pakora, was ranked above acceptable range by the panel of judges for various quality attributes.
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O estudo do processo de conservação do açaí, através da aplicação da tecnologia de obstáculos, foi feito pela combinação dos seguintes fatores: diminuição do pH a 3,5 (0,5% p/p de ácido cítrico), tratamento térmico (82,5°C durante 1 minuto), redução da atividade de água pela adição de sacarose (10, 25 e 40% p/p) e adição de sorbato de potássio (0,075 e 0,15% p/p). Um planejamento experimental completo do tipo fatorial 22 foi usado na elaboração das formulações do produto, que foram armazenadas a 25°C na ausência de luz durante 5 meses. As formulações 1, 2 e 8 foram rejeitadas sensorialmente antes dos 3 meses de estocagem. No entanto, as formulações 2 (40%p/p de sacarose), 4 (40%p/p de sacarose e 0,15%p/p de sorbato de potássio) e 5 (25%p/p de sacarose e 0,075%p/p de sorbato de potássio) apresentaram boa aceitação sensorial após os 5 meses de armazenamento.
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Fruit preservation by hurdle technology is based on combinations of low levels of various antimicrobial factors (hurdles) acting synergistically resulting in a shelf stable high moisture, fresh-like product. The objective of this work was to evaluate the stability of mango cubes obtained by combining the following hurdles: water activity reduction, pH reduction, and chemical preservation. Tommy Atkins mangoes, previously washed, sanitized and peeled, were cut into cubes of approximately 8 cm3. The cubes were osmotically dehydrated under stirring (150 rpm) at 46ºC in a sucrose solution at 65.5oBrix added with 2% citric acid and 0.2% potassium sorbate, during two hours. The product was drained, packed in low-density polyethylene bags and stored at room temperature (about 25ºC) during three months. The combination of hurdles on the final product (water activity, 0.96; pH, 3.99; potassium sorbate content, 396 mg.kg-1) was not effective to make it shelf stable, since the count of yeasts and molds increased. The cubes underwent pH reduction and color losses during storage. Furthermore, the acceptance of the product, as well as, the mango flavor intensity, decrease significantly with storage time.
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O estudo do processo de conservação do açaí, através da aplicação da tecnologia de obstáculos, foi feito pela combinação dos seguintes fatores: diminuição do pH a 3,5 (0,5% p/p de ácido cítrico), tratamento térmico (82,5°C durante 1 minuto), redução da atividade de água pela adição de sacarose (10, 25 e 40% p/p) e adição de sorbato de potássio (0,075 e 0,15% p/p). Um planejamento experimental completo do tipo fatorial 2² foi usado na elaboração das formulações do produto, que foram armazenadas a 25°C na ausência de luz durante 5 meses. As formulações 1, 2 e 8 foram rejeitadas sensorialmente antes dos 3 meses de estocagem. No entanto, as formulações 2 (40%p/p de sacarose), 4 (40%p/p de sacarose e 0,15%p/p de sorbato de potássio) e 5 (25%p/p de sacarose e 0,075%p/p de sorbato de potássio) apresentaram boa aceitação sensorial após os 5 meses de armazenamento.The study of preservation process of the assai pulp through the application of hurdle technology was done by the application of the following preservation factors: reduction of pH at about 3.5 by the addition of 0.5% w/w of citric acid, thermal treatment (82.5°C for 1 min), reduction of the water activity by the addition of sucrose (10, 25 and 40% w/w) and addition of potassium sorbate (0.075 and 0.15% w/w). A full factorial experimental design was used in the elaboration of the formulations of the product, that were stored at 25°C in the absence of light for 5 months. The formulations 1, 2 and 8 were discarded sensorially before 3 months storage. Besides, the formulations 2 (40%w/w of sucrose), 4 (40%w/w of sucrose and 0.15%w/w of potassium sorbate) and 5 (25%w/w of sucrose and 0.075%w/w of potassium sorbate) showed a good overall acceptability shelf-life time of 5 months.
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2 Abstract: Studies were carried out on the inhibition of three fungi isolated from sorrel drink (Zobo) using water extracts of Zingiber officinale (Ginger), Piper guineense (West African Black Pepper) as well as heat as hurdles. The fungi isolated and identified were Aspergillus flavus, A.. niger and unidentified Yeast. The spice extracts at concentrations 1-6 ml reduced fungal growth. As the spice concentration was increased, there was a decrease in fungal biomass in the drink when compared with the control. A combination of both spice extracts at different ratios also reduced fungal growth. When the fungi were challenged with 100°C heat for different periods of times (mins), growth reduction also occurred. The further combination of heat treatment with the combined spice treatment inhibted growth tremendously.
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A preservation process based on the "hurdle" effect for obtaining a shelf-stable banana purée was developed. The microbial stability of the purée was challenged with inoculation of osmophilic and non-osmophilic yeasts, various molds, Bacillus coagulans, Clostridium pasteurianum and Clostridium butyricum. It was shown that growth of both native and inoculated flora may be prevented for at least 120 days storage in banana purée by adjusting water activity (aw) to 0.97, pH to 3.4, adding 250 ppm of ascorbic acid (AA), 100 ppm of potassium sorbate (KS) and 400 ppm of sodium bisulphite (NaHSO3), and applying a mild heat treatment.
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In this study, the hurdle technology approach was used to prevent fungal growth of common spoilage fungi in naturally fermented black olives (Alternaria alternata, Aspergillus niger, Fusarium semitectum andPenicillium roqueforti). The factors studied included a combination of different concentrations of potassium sorbate (100 up to 1000 mg/L), a range of pH values (4.5, 5, 5.5, 6, and 6.5) and levels of NaCl (0, 3.5, 5, 7.5, and 10%).Alternaria alternata was the most sensitive fungus whereasP. roqueforti was the most resistant fungi against all hurdle factors. The combination of all hurdles completely inhibitedA. alternata andF. semitectum by lowest inhibitory factors, such as 100 mg/L potassium sorbate with 3.5% NaCl at pH 5. On the other hand, at pH 5, A.niger andP. roqueforti were totally prevented by a combination of 300 mg/L potassium sorbate with 10% NaCl and 400 mg/L potassium sorbate with 7.5% NaCl, respectively. Potassium sorbate and 5–10% NaCl interaction had significant stimulation effect onp. roqueforti andA. niger (p<0.05). This study indicates that potassium sorbate is a suitable preserving agent to inhibit growth of fungi in fermented products of pH near 4.5 regardless levels of NaCl. For products of slightly higher pH, the addition of potassium sorbate is suggested in combination with NaCl.
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A process has been developed for the preparation of shelf-stable, ready-to-eat (RTE) shrimps using a combination of hurdles. The hurdles employed to cooked marinated shrimps included reduced water activity (0.85±0.02), packaging and γ-irradiation (2.5 kGy). Microbiological analysis revealed a dose dependent reduction in total viable count and Staphylococcus species. In nonirradiated samples a visible mold growth was seen within 15 days of storage at ambient temperature (25±3 °C). No significant changes in textural properties and sensory qualities of the product were observed on radiation treatment. These RTE shrimps were microbiologically safe and sensorially acceptable even after 2 months of storage at ambient temperature.
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A number of ready-to-use shelf-stable intermediate-moisture (IM) spiced mutton and spiced chicken products were developed with a combination of hurdles (reduced moisture, vacuum packing, and irradiation). The water activity of the products was reduced to about 0.80 either by grilling or by hot-air drying. These IM products were vacuum packed and subjected to gamma radiation processing at 0 to 10 kGy. Microbiological analyses revealed a radiation dose-dependent reduction in total viable counts and in numbers of Staphylococcus species. IM meat products that did not undergo radiation treatment showed visible mold growth within 2 months. The products subjected to irradiation at 10 kGy showed an absence of viable microorganisms and also retained high sensory acceptability for up to 9 months at ambient temperatures.
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The influence of acid, ethanol, and NaCl on the cellular components and inactivation of Escherichia coli were evaluated using differential scanning calorimetry. Cell viability was assessed using plate counting. The thermal stability for ribosomal subunit denaturation and the total apparent enthalpy decreased with increasing ethanol, salt, and acid concentrations. The reduction of the ribosomal subunit denaturation peak was the primary contributor to the decrease in the total apparent enthalpy. Thermograms indicated that even at concentrations at which less than a 0.4-log reduction of cell viability with a concomitant minimal reduction of total apparent enthalpy occurred, a decrease in onset temperature of ribosomal transition was evident. Acid treatments at pH 3 induced by HCl and by 0.4 M acetic acid caused the DNA denaturation temperature in vivo to decrease. Application of chemical treatment prior to heat treatment noticeably reduced the viability of E. coli cells at all the heat treatment temperatures (60, 62.5, and 65 degrees C) compared with that of heat treatment alone, suggesting an increased sensitivity of bacteria to heat treatment. Differential scanning calorimetry in vivo can be used to assess the effectiveness of hurdles when thermal processing technologies with hurdles are designed.
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A hurdle technology approach has been applied to control common mold species causing spoilage of intermediate moisture bakery products (Eurotium spp., Aspergillus spp., and Penicillium corylophilum), growing on a fermented bakery product analogue (FBPA). The factors studied included a combination of different levels of weak acid preservatives (potassium sorbate, calcium propionate, and sodium benzoate; 0-0.3%), pH (4.5-5.5), and water activity (a(w); 0.80-0.90). Potassium sorbate was found to be the most effective in preventing fungal spoilage of this kind of products at the maximum concentration tested (0.3%) regardless of a(w). The same concentration of calcium propionate and sodium benzoate was effective only at low a(w) levels. On the other hand, potassium sorbate activity was slightly reduced at pH 5.5, the 0.3% being only effective at 0.80 a(w). These findings indicate that potassium sorbate may be a suitable preserving agent to inhibit deterioration of a FBPA of slightly acidic pH (near 4.5) by xerophilic fungi. Further studies have to be done in order to adjust the minimal inhibitory concentration necessary to obtain a product with the required shelf life.
Article
The effect of different 'hurdles' viz., water activity (a w), pH and heat treatment (F) on the rheological properties viz., hardness and chewiness of fried paneer immediately after processing as well as during storage was studied by response surface methodology (Hoke's design). The different levels studied were : a w 0.90, 0.94, 0.98; pH 4.7, 5.3, 5.9; F-value 0.2, 0.5, 0.8 and potassium sorbate 0.0, 0.05, 0.10 %. These parameters profoundly influenced the hardness and chewiness during processing as well as during storage. The data were fitted to second order polynomial regression equation. Constants for the best fit polynomial equation for the change in rheological characteristics, linear-linear form in case of effect of processing and In-linear form in case of storage changes in chewiness have been given. Using these equations, the changes in hardness and chewiness as a function of the above parameters have been predicted and displayed in the form of response surfaces. Decrease in a w and pH increased hardness and chewiness, whereas heat treatment decreased them. Based on the predicted response surfaces, the minimal changes occurred in hardness at the following values: a w 0.90-0.93 at pH 5.1-5.9; a w 0.918-0.948 at F-value 0.37-0.79. Minimal changes in chewiness occurred at a w 0.90-0.97 at pH 4.7-5.3; a w 0.900-0.945 at F-value 0.20-0.35. Synergistic effect of these parameters was also observed. These observations will be of significance in canning of paneer and paneer-based products.
Article
The fluctuation of three treatments/hurdles - i.e. the temperature (gradient 17°C to 27°C, step 1°C), the water activity (aw of 0.990, 0.985, 0.980) and the preservative sodium nitrite, - are examined with regard to the microbial behaviour of Escherichia coli. The bacterial counts of the inoculum were 1×103 and 1×106 cfu/ml. The results indicate that the effects of the hurdles can show very complex dependences. In no case the hypothesis of a simple additive effect between different hurdles is sufficient and correct. Usually the microorganisms show extremely various behaviour patterns. The investigations presented here document the necessity to consider the 'hurdle-model' from a quantitative point of view. Not only the influence of the temperature on the activity of the microorganisms will be defined by the other environmental conditions, but the efficiency of an additive (preservative) like sodium nitrite can be changed by the environmental influence too. The goal of this investigation is to support a predictive microbiology.
Article
Storage life of pineapple, mango and papaya fruit chunks preserved by hurdle technology was studied using the hurdles pH, mild heat treatment preservatives and packaging. Pineapple and mango fruit chunks, blanched in syrup at 85°C for 5 min, dipped in syrup containing 340 mg of potassium metabisulphite/kg and 413 mg sodium benzoate/kg for 8 h and packed in 150 gauge polypropylene pouches showed acceptable sensory and microbiological qualities up to a period of 30 days at 27°C and 60 days at 2°C and had SO2 content of 65-85 mg/kg and benzoic acid 150-200 mg/kg. The papaya chunks treated with increases in levels of preservatives to 680 mg potassium metabisulphite/kg and 826 mg sodium benzoate/kg exhibited good storage stability up to 90 days at 2°C and ambient temperature.
Article
Combination preservation technique was adopted to stabilize spice-based high moisture (60-70%) knol-khol and cauliflower. The process comprised of additives including 4% sodium chloride to keep water activity (aw) in the range 0.92-0.95, 0.5%, citric acid to reduce pH <4.5 and potassium metabisulphite as anti-browning agent. The products were packed in polypropylene pouches and subjected to 3, 5 and 8 kGy irradiation doses. The storage studies at ambient temperature revealed that the products were microbiologically stable while the browning intensified at higher dosages and the products became softer after 4 months of storage. The commercial spices showed the presence of coliforms and Aspergillus flavus in the dehydrated powder before irradiation. Irradiation in addition to acid and salt infusion treatments reduced the microbial counts from an initial value of 104 to 101 cfu/g and Asp. flavus was absent. It was concluded that irradiation at 5 kGy was useful as one of the preservative factors in stabilizing high moisture spice based knol-khol and cauliflower products for 4 months at ambient temperature.
Article
A paneer - based convenience food (paneer curry) was developed using hurdle technology. The product was so formulated as to have a water activity of 0.95, pH 5.0, potassium sorbate 0.1% and processed at F-value of 0.8 in tins. The changes in rheological properties of paneer portion as well as chemical and sensory changes during storage at 30°C were studied. The product kept well for about one month and was found to have better quality than the heat-sterilised (15.0 F-value) product stored under similar conditions.
Article
Although Listeria monocytogenes is readily destroyed by thermal treatment, the factor that makes it particularly difficult to control in nonpasteurized foods is its ability to grow at refrigeration temperatures. In heat-sensitive products, nonthermal technologies such as pulsed electric fields (PEF) as part of hurdle technology could minimize the presence of foodborne pathogens. The influence of PEF-treatment conditions, inoculum size and substrate conditions on the inactivation and recovery of L. monocytogenes in a traditional low-acid, vegetable beverage was investigated. The combined effect of PEF, low temperature (5C) and low inoculum level contributed to slow down the recovery of sublethally injured cells. However, at 12 or 16C, this elongation of the lag phases after PEF treatment observed for low inoculum levels of cells was not achieved. Therefore, to prevent the development of L. monocytogenes in low-acid products by PEF, it may be necessary to combine it with low refrigeration temperatures during distribution and storage, as well as to achieve a very low initial contamination by pathogens in the raw ingredients.
Article
The objective of the present study was to reduce nitrite content in hot dogs using hurdle technology without sacrificing product safety and quality. In the present study, the water activity of the hot dog was adjusted to 0.95 by the addition of humectants. Although the pH at the hot dog was adjusted with Glocono-delta-lacton to 5.4, the product had (p > 0.05) the least acceptance on account of the organoleptic changes (sour taste). Moreover, the temperature of 80 ± 1 °C for an hour with the aim of achieving an internal temperature of 75 °C was applied. Subsequently, the temperature of the hot dog samples reduced to around 5–6 °C within 40–45 min, and afterwards the sausages were kept at chilled temperature (>3 °C but ⩽10 °C) throughout their shelf life. There was a decrease in total aerobic counts in hurdle treated hot dogs (with 50 ppm nitrite), compared to the control (with 120 ppm nitrite), whereas Clostridium perfringens counts and Clostridium botulinum detection were the same (p < 0.05) in both hurdle treated and control samples. The obtained results of present study clearly showed that both hurdle treated sample and control had the same (p < 0.05) overall acceptability and sensory attributes.
Article
The stability of unwashed and washed mince from Spanish sardines (Sardinops sagax) treated by mild heating, low pH (5.7–6.0), potassium sorbate (0.05–0.2%), and sodium chloride (2.0–6.0%) was studied. Addition of 6% salt and 0.2% sorbate at pH 5.7 was the best factor combination and when accompanied by heat treatment (10min, 80°C) produced a partly cooked product, microbiologically stable at 15°C for at least 15 d. Washing and mild heat treatment (2min, 80°C) helped to reduce the initial microbial load of the mince by a factor of 100 and, in combination with the above formulation, the product had a storage life of over 15 d at 15°C, compared with less than 3d for the original unwashed mince.
Article
Carrot (Daucus carota) can be highly perishable and difficult to preserve fresh for long periods at ambient temperature and humidity. Studies on grated carrots were carried out for the development of a shelf-stable moist-preservation process based on infusion of additives using hurdle technology. Additives comprising 3.0% sodium chloride (to reduce water activity [Aw] to 0.94), 0.9% citric acid (to reduce pH to below 4.5), 1.0% sodium citrate and 0.2% sodium benzoate (as antimicrobial agents) were followed by partial dehydration. The product was stored in flexible polymeric pouches. The physical, chemical and pathological stability was monitored during storage at ambient temperatures (19–33C). The partially dehydrated grated carrots (moisture 66.2%) were acceptable for more than six months at ambient temperature with the retention of carotenoid up to 82.5%. The product was microbiologically safe throughout the study.
Article
Tomato puree was subjected to combined treatments of high hydrostatic pressure and natural additives [citric acid and sodium chloride (NaCl)]. Their effects on the most important quality parameters of tomato puree as colour and viscosity, and biochemical parameters as enzymatic activities (polyphenoloxidase, peroxidase, and pectin methylesterase) and total protein content, and microorganisms (total microbial counts and yeasts and moulds) were studied. Response surface methodology was employed where the experiment was carried out according to a central composite face-centred design. The variables ranges used were: 50–400MPa (pressure), 0–0.8% w/w (concentration of NaCl) and 0–2% w/w (concentration of citric acid) while temperature and holding time of high pressure treatments were constants at 25C and 15min respectively. The results showed that enzymatic inactivation was significantly improved with these combined treatments at high values of pressure and concentration of additives. A very significant reduction of 4 logarithmic units was observed when pressure was increased to 400MPa for total microbial counts. Thus, combined "hurdles" may be effective to produce minimally processed tomato products with optimal sensorial and microbiological characteristics.
Article
Contamination of Gorgonzola cheese surface by Listeria is a difficult problem to solve by only applying good manufacturing practices. Treating of the cheese rind at the end of ripening may be a tool to improve cheese safety. The aim of this study was to evaluate the effect of a high pressure water spray washing technology in reducing Listeria load from Gorgonzola cheese rind without using oxidizing agents.The surface of Gorgonzola cheese was contaminated (up to 107 cfu g−1 of scraped rind) with a mixture of four strains of Listeria innocua. The count of Listeria was made by scraping (2 mm depth) the rind of the cheese. The contaminated cheeses were then washed at different pressures, ranging from 1 to 5 MPa for 1 min. The lower the pressure, the lower was the removal of Listeria. A reduction of up to 99.89% was achieved washing the cheese at 5 MPa, followed by rinsing at 1 MPa for 1 min. Changing the inoculum size (102, 104, and 107 cfu g−1), did not change the efficacy of Listeria removal, when the same water pressure was applied.The washing of Gorgonzola cheese with pressurized jet water, without adding any preservative to the water, can be considered a further important physical hurdle, in controlling pathogenic bacteria and improving cheese safety.
Article
A preservation process to achieve microbial and sensorial stability of papaya slices stored at 25°C at least during five months was developed. The preservation process was based on ‘combined methods technology’, and included the combination of the following factors: a mild heat treatment (blanching), a water activity reduction, a pH decrement, and the addition of potassium sorbate and sodium bisulfite. The obtained fruit stored at 5 and 25°C during five months was evaluated for color and texture changes, sulfite and potassium sorbate degradation kinetics, changes of aerobic plate counts, yeasts and molds, ascorbic acid retention and sensorial quality changes.Moisture and soluble solids contents, pH, and water activity remained almost constant and the product obtained was microbiologically sound during storage. There was an enzymatic sucrose hydrolysis that reduced the water activity more than expected, which helps to assure the microbial stability. Total sulfite and potassium sorbate concentrations were reduced during storage at 5 and 25°C, giving final concentrations 62 and 66%, and 40 and 60% of the initial concentrations, respectively. Ascorbic acid content of papaya was reduced during processing and storage. Color, texture and sensory evaluation reveal that there were no significant differences between samples stored at 5 and 25°C. The papaya slices obtained showed a good overall acceptability (initial mean score 7·25) even after five months of storage at 25°C (final mean score 6·73)
Article
Safe and shelf-stable natural casing were prepared using a combination of hurdles viz. reduced water activity, packaging and gamma irradiation. Washed lamb intestines were treated with common salt to reduce water activity to 0.80 ± 0.02, packed in polyethylene bags and subjected to gamma-irradiation (5 and 10 kGy). Control non-irradiated samples had high total viable counts (106 CFU/g), aerobic spores (103 CFU/g), spores of sulphite reducing clostridia (103 CFU/g), potentially pathogenic bacteria such as staphylococci (104 CFU/g) and coliforms (102 CFU/g). Treatment with gamma radiation resulted in a dose dependent reduction in counts of these microbes. A dose of 5 kGy was sufficient to reduce total viable counts by three log cycles; spore counts by two log cycles and completely eliminate staphylococci and coliforms. Samples subjected to a 10 kGy dose were devoid of any viable microbes. The reduced water activity of the product prevented growth of the microbes in natural casings during storage at room temperature. Sausages prepared using hurdle processed natural casing were examined for sensory and textural properties. It was observed that product acceptability and mechanical strength was not affected by radiation processing. Our studies indicated that shelf-stable and safe natural casing could be prepared using a combination of hurdles.
Article
In earlier research, we studied the influence of water activity (aw) on the stability and safety of meats. It became obvious that in addition to aw other factors (hurdles) determine the microbial stability of foods. From this understanding the hurdle effect was conceived, and later hurdle technology was derived, which was applied to shelf stable products and intermediate moisture foods based on meat. Similar principles are used for the preservation of many other foods, in industrialized as well as in developing countries, especially for foods storable without refrigeration. A linkage of hurdle technology with the hazard analysis critical control points (HACCP) concept has been achieved, and the relationship to predictive microbiology is now being studied. Fundamental issues, such as lipid oxidation in membranes and the homeostasis of microorganisms, are currently being investigated in the light of hurdle technology. This approach is also applicable for quality aspects of foods. To secure the total desired quality of a food, the safety and quality hurdles should be kept within the optimal range.
Article
Foods preserved by combined methods remain stable and safe even without refrigeration, and are high in sensory and nutritive properties due to the gentle processes applied. The concept is gaining ground in industrialized as well as in developing countries. Several topics will be discussed briefly: (1) water activity, (2) hurdle effect, (3) hurdle technology (4) shelf stable products, (5) intermediate moisture foods, and (6) perspectives.
Article
Hydrodynamic pressure processing (HDP), a novel non-thermal technology that uses a small amount of explosive (100 g) to generate a supersonic–hydrodynamic shock wave in a water filled steel container (54 L) was evaluated for inactivation of Escherichia coli O157:H7 (EHEC) in ground beef. The ground beef was inoculated with a six strain cocktail of E. coli O157:H7 at three different concentrations (103, l04 and l06 CFU/g). The following strains of E. coli O157:H7 were used in the cocktail: 3027-93, 3055-93, C7927, 43888, C9490, and green fluorescent protein-expressing E. coli O157:H7 B6-914 (GFP EC). Inoculated ground beef was wrapped in polyethylene wrap, vacuum packaged into multilayer barrier bags, heat shrunk and treated with HDP. The initial concentrations of EHEC were 1.29 × 103, 2.88 × 104, and 2.19 × l06 CFU/g. After HDP treatment, the EHEC populations were reduced (P < 0.05) to 9.12 × 102, 2.40 × 104, and 1.91 × l06 CFU/g, respectively. A similar trend was observed for GFP EC which was also enumerated from the cocktail. The GFP EC initial populations of 4.26 × l02 and 3.72 × l03 CFU/g were reduced to 3.47 × 102, and 3.09 × l03 CFU/g, respectively. Although the reduction in EHEC populations due to HDP treatment was statistically significant, the practicability of the reduction was marginal. Therefore, other hurdle parameters should be included along with the HDP treatment for more practical inactivation of EHEC in ground beef.
Article
The effects of combining techniques such as addition of sorbic acid, modification of water activity (aw), reduction of pH, modification of the packaging atmosphere and control of the storage temperature on the microbiological shelf life of avocado purée were evaluated during four months of storage. Results show that the addition of 300 mg/kg of sorbic acid can extend the stability of the product native microflora for storage periods of up to four months. Vacuum packaging as well as storage at 4 °C was also found to have a significant influence over the control of yeast and mould populations and could preserve avocado purées during 112 days without addition of antimicrobial. The addition of maltose to reduce aw to 0.96 resulted in slightly more stable purées but would impart important changes to the product palatability.
Article
This paper presents the processes developed for preserving ‘high moisture fruit products’ (peach, pineapple, mango, papaya, chicozapote, banana) in seven countries in the frame of CYTED-D Program. The new technologies were based on the combination of a mild heat treatment, a slight water activity (aw) reduction, and addition of antimicrobials (‘hurdle effect’). These minimal processes are energy efficient, satisfactory to preserve fruits in situ and open new possibilities for export markets. High moisture fruit products are shelf-stable during at least 4–8 months of storage.
Article
Many intermediate moisture foods (IMF) in Latin America are actually foods preserved against microbial spoilage by combined methods (CM) using only a few factors and having low technological development. Water activity (aw), the main preservation factor used, is controlled through the addition of solutes or in extreme cases by dehydration. Developments in CM technology are illustrated and discussed through two examples: the stabilization of concentrated cheese whey and the long-term, bulk preservation of fruit pieces.
Article
Beef trimmings were treated with 0.5% cetylpyridinium chloride followed by 10% trisodium phosphate (CT), 200-ppm chlorine dioxide followed by 0.5% cetylpyridinium chloride (CLC), 200-ppm chlorine dioxide followed by 10% trisodium phosphate (CLT), or 2% lactic acid followed by 0.5% cetylpyridinium chloride (LC). The trimmings were ground, packaged and sampled at 0, 1, 2, 3 and 7 days of simulated retail display and compared with an untreated control (C) for instrumental color, sensory color and odor and TBARS (Thiobarbituric acid reactive substances) characteristics. Ground beef from the LC and CLC treatments were lighter (P <0.05; L*) than C. The LC and CT ground beef samples were similar (P > 0.05) in vividness to C. On day 3, CT was scored redder (P <0.05) than C. Therefore, the use of CT, CLT, CLC and LC had little impact on ground beef color and CT improved ground beef color shelf life.
Article
Hurdle technology is used in industrialized as well as in developing countries for the gentle but effective preservation of foods. Previously hurdle technology, i.e., a combination of preservation methods, was used empirically without much knowledge of the governing principles. Since about 20 years the intelligent application of hurdle technology became more prevalent, because the principles of major preservative factors for foods (e.g., temperature, pH, a(w), Eh, competitive flora), and their interactions, became better known. Recently, the influence of food preservation methods on the physiology and behaviour of microorganisms in foods, i.e. their homeostasis, metabolic exhaustion, stress reactions, are taken into account, and the novel concept of multitarget food preservation emerged. In the present contribution a brief introduction is given on the potential hurdles for foods, the hurdle effect, and the hurdle technology. However, emphasis is placed on the homeostasis, metabolic exhaustion, and stress reactions of microorganisms related to hurdle technology, and the prospects of the future goal of a multitarget preservation of foods.
Article
The antimicrobial effects of spices and herbs from 18 plant species were examined on a foodborne pathogen, Vibrio parahaemolyticus, with the use of combinations of temperatures and nutrient levels. Basil, clove, garlic, horseradish, marjoram, oregano, rosemary, and thyme exhibited antibacterial activities at incubation of 30 degrees C, while with the exception of horseradish, the same spices and additional 7 species exhibited the activities at 5 degrees C. The lowest MIC (minimum inhibitory concentration) was 0.125% observed in clove and marjoram at 30 degrees C in a nutrient rich medium. Lowering of incubation temperature produced little effect on the MICs except for turmeric. The decreasing of the MIC in turmeric appeared to be basically attributed to the sensitivity of the bacterium to coldness. In nutrient poor medium, the lowest was 0.001 and 0.00025% in marjoram at 30 degrees C and at 5 degrees C, respectively. The sensitivity to several spices and herbs was similar among different clinical serotypes including the emerging strain O3:K6. These results suggest that the spices and herbs can be practical for protecting seafood from the risk of contamination by V. parahaemolyticus and used in hurdle technology with low temperature.
Article
The effect of hen egg white lysozyme (HEWL) and bacteriophage lambda lysozyme (LaL) in combination with high pressure (HP) treatment on the inactivation of four gram-negative bacteria (Escherichia coli O157:H7, Shigella flexneri, Yersinia enterocolitica and Salmonella typhimurium), was studied in skim milk (pH 6.8; a(w) 0.997) and in banana juice (pH 3.8; a(w) 0.971). In the absence of lysozymes, S. flexneri was more sensitive to HP in milk than in banana juice, while the opposite was observed for the other three bacteria. In combination with HP treatment, LaL was more effective than HEWL on all bacteria in both milk and banana juice. Depending on the bacteria, inactivation levels in banana juice were increased from 0.4-2.7 log units by HP treatment alone to 3.6-6.5 log units in the presence of 224 U/ml LaL. Bacterial inactivation in milk was also enhanced by LaL but only by 0.5-2.1 log units. Under the experimental conditions used, LaL was more effective in banana juice than in milk, while the effectiveness of HEWL under the same conditions was not significantly affected by the food matrix. This effect could be ascribed to the low pH of the banana juice since LaL was also more effective on E. coli in buffer at pH 3.8 than at pH 6.8. Since neither LaL nor HEWL are enzymatically active at pH 3.8, we analysed bacterial lysis after HP treatment in the presence of these enzymes, and found that inactivation proceeds through a non-lytic mechanism at pH 3.8 and a lytic mechanism at pH 6.8. Based on these results, LaL may offer interesting perspectives for use as an extra hurdle in high pressure food preservation.
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