Article
To read the full-text of this research, you can request a copy directly from the authors.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... The production of slightly acidic to neutral EW with conventional systems containing a membrane usually requires electrolysis of hydrochloric acid itself, use of hydrochloric acid as a pH adjuster, or an additional process, such as the mixing of the two types of EW in different amounts (Umimoto et al. 2013). Recently, the development of new electrolysis systems with and without the use of membranes has been shown to be efficient to generate acidic to neutral EW (Gómez-López et al. 2013b;Umimoto et al. 2013). In the new developed systems without the use of membranes, the species (oxidative species and protons H + as well as reductive species and OH − ) are generated and automatically mixed so the pH is not strongly influenced, but it will depend on the mixture process. ...
... Figure 4 shows experimental results obtained when electrolyzed water was generated using boron-doped diamond (BDD) electrodes with and without the addition of salt. The effect of different operating conditions including current density, recirculation flow rate, and electrode doping level to inactivate microorganisms and decrease COD has been determined for lettuce process water under dynamic conditions (Gómez-López et al. 2013b. ...
... However, Schmalz et al. (2009) demonstrated that the direct bacterial inactivation of chloridecontaining wastewater by the ROS (mainly •OH) radicals generated during electrochemical disinfection using BDD electrodes was negligible. On the other hand, it should be taken into account that electrochemical disinfection is largely dependent on cell configuration as well as the flow rate and the current density (Gómez-López et al. 2013b). The inactivation rate accelerates with increasing current density caused by a faster generation of electrochemical oxidants. ...
Article
This chapter focuses on the use of electrolyzed oxidizing (EO) water for washing fresh and fresh-cut produce. It revises the different types of EO water, its advantages and disadvantages, types of generation devices, the microbial inactivation mechanism, and factors affecting its efficacy. It also summarizes the effect of EO water on pathogenic and spoilage microorganisms and produce shelf life, vegetable physiology, sensory quality, and nutritional and phytochemical composition, as well as the potential persistence of residues and formation of toxic by-products and EO regulatory status.
... The production of slightly acidic to neutral EW with conventional systems containing a membrane usually requires electrolysis of hydrochloric acid itself, use of hydrochloric acid as a pH adjuster, or an additional process, such as the mixing of the two types of EW in different amounts (Umimoto et al. 2013). Recently, the development of new electrolysis systems with and without the use of membranes has been shown to be efficient to generate acidic to neutral EW (Gómez-López et al. 2013b;Umimoto et al. 2013). In the new developed systems without the use of membranes, the species (oxidative species and protons H + as well as reductive species and OH − ) are generated and automatically mixed so the pH is not strongly influenced, but it will depend on the mixture process. ...
... Figure 4 shows experimental results obtained when electrolyzed water was generated using boron-doped diamond (BDD) electrodes with and without the addition of salt. The effect of different operating conditions including current density, recirculation flow rate, and electrode doping level to inactivate microorganisms and decrease COD has been determined for lettuce process water under dynamic conditions (Gómez-López et al. 2013b. ...
... However, Schmalz et al. (2009) demonstrated that the direct bacterial inactivation of chloridecontaining wastewater by the ROS (mainly •OH) radicals generated during electrochemical disinfection using BDD electrodes was negligible. On the other hand, it should be taken into account that electrochemical disinfection is largely dependent on cell configuration as well as the flow rate and the current density (Gómez-López et al. 2013b). The inactivation rate accelerates with increasing current density caused by a faster generation of electrochemical oxidants. ...
Article
Full-text available
Water disinfection is one of the most critical processing steps in fresh-cut vegetable production. Technologies capable for the efficient disinfection of process water and recycled water would allow reducing wastewater and have less impact on the environment. Among the chemical disinfectants, hypochlorite solutions are still the most widely used. Electrochemical disinfection of the wash water has been demonstrated to be effective in eliminating a wide spectrum of pathogens in process water. Both hypochlorite solutions and electrochemically produced chlorine compounds, in particular hypochlorous acid, are effective disinfectants when adequate doses are used. A new electrochemical process using boron-doped diamond electrodes can generate additional reactive oxidant species than chlorine and further enhance the disinfecting capacity. However, there are pros and cons on the use of one or other disinfectant agents. In this review, the technological advantages and the limitations of electrolyzed water, particularly regarding the organic matter content, are discussed and compared to the use of hypochlorite.
... Thus, to apply this technology during washing of a fresh-cut processing line, addition of salts is needed to increase the inactivation rate and to obtain a residual effect on the washing tank [14]. Conditions including high current density (180 mA/cm 2 ), high flow rate (750 l/h) and high doping level (8000 mmol/mol) seem to provide a disinfection efficiency suitable to decrease the chance of bacterial cross-contamination in the fresh-cut industries, while saving on water consumption and decreasing the amount of wastewater effluents [48]. Recent studies carried out by our group have evidenced that the use of this technology in the fresh-cut processing line could represent a good alternative to NaOCl [44,48]. ...
... Conditions including high current density (180 mA/cm 2 ), high flow rate (750 l/h) and high doping level (8000 mmol/mol) seem to provide a disinfection efficiency suitable to decrease the chance of bacterial cross-contamination in the fresh-cut industries, while saving on water consumption and decreasing the amount of wastewater effluents [48]. Recent studies carried out by our group have evidenced that the use of this technology in the fresh-cut processing line could represent a good alternative to NaOCl [44,48]. However, taking into account the current operational cost, this technology does not represent a good alternative for the fresh-cut industry. ...
Article
Full-text available
Purpose of review: This review discusses the application of physical treatments including ionizing and non-ionizing (UV-C) radiation, ultrasound, electrolyzed water and cold plasma as decontamination methods to reduce surface and internal contamination of the product and to avoid cross-contamination in process wash water. Potential combinations of physical and chemical treatments are also discussed. This manuscript shows the suitability of specific physical treatments to reduce microbial contamination of fresh produce as well as their implementation during processing of fruits and vegetables.Main findings: Data presented in this review highlight which physical methods are suitable processing technologies to be applied without detrimental effects on the organoleptic properties and nutritional quality of fresh fruits and vegetables. The microbiological tests carried out after pathogen inoculation offer insights into the antibacterial capacity of these treatments on different produce surfaces as well as in the process wash water. Although the physical methods described in this manuscript have potential use in inactivating foodborne pathogens, high operational costs, consumer acceptance and difficulties to eliminate internalized microorganisms make it difficult to introduce them as suitable intervention strategies to assure the safety of fresh produce.Directions for future research : This review shows the current application of selected physical methods to reduce microbial risk of fresh produce and also highlights the limitations of these technologies. Although most of the physical methods are able to reduce the superficial microbiota of fruits and vegetables they largely fail in eliminating internalized microorganisms. However, we believe that more research and technological advances might demonstrate the suitability of these technologies for producers and consumers in the near future. Therefore, further studies might lead to the development of appropriate largescale equipment for sanitation techniques for fresh fruits and vegetables and disinfection agents able to be implemented on processing lines.
... Our results reveal that physical filtration of E. coli was not the main mechanism for bacterial removal in our system, since applying a low current density of 2.1 µA/cm 2 resulted in a 3.19 ± 0.02-fold higher bacterial inactivation than that obtained in control disinfection experiments (with no current applied). This behavior is consistent with previous studies, showing that increasing the j applied is often associated with achieving high bacterial inactivation rates, while bacteria inactivation without any electrochemical perturbation is often trivial [41][42][43][44]. ...
Article
Although water and wastewater have a myriad of contaminates, waterborne pathogens represent the main threat to negatively affect public health, especially in developing countries. Therefore, there is an urgent demand to develop reliable, highly efficient water disinfection technologies. Here, we developed a high-throughput, flow-through silver-magnetite (Ag-Fe3O4)-modified electrochemical system, which allows high bacterial inactivation with a low energy consumption owing to the enhanced convective mass transport. The reactive electrochemical disinfection system equipped with the Ag-Fe3O4-modified anodes exhibited high bacterial inactivation efficiency (up to 5 logs) at a relatively low applied current density (i.e., 2.1 to 20.8 µA/cm²) with a slow, controllable release of Ag ions at a ppb level and low energy consumption of 0.3 to 0.9 Wh/m³. Furthermore, the electrochemical system exhibited a reasonably high bacterial inactivation efficiency of E. coli, Salmonella, and Pseudomonas aeruginosa when fed with secondary-treated sewage at a water flow rate of 5 mL/min and an applied current density of 104 µA/cm², suggesting that the electrochemical membrane devices can potentially use for water and wastewater disinfection.
... [221] Their main applications are disinfection of processing utensils, meat and products, cutting boards, and in livestock management, and in latest times, sanitation of water chiefly used for fresh fruit and vegetable washing. [222,223] The use of EW for managing food-borne diseases and the growth of spoilage microbes in processed vegetables were also reported. [224] The harmful effect of EW in combination sodium bicarbonate (1.25%) on inhibition of Penicillium spp. ...
Chapter
The multitasked Nitric oxide (NO) is a highly reactive, gaseous molecule that is endogenously produced in the plant cells through various routes. In the plant, NO participates in numerous physiological processes including growth and development as well as adaptation against (a)biotic stresses. At the molecular level, NO acts as a redox-related signaling molecule whose function entirely depends on two factors (concentration and spatial generation pattern). Once generated, it directly or indirectly interacts with other redox-related molecules (O2−, H2O2, H2S, NO2−) and potentially interacts with various biomolecules including proteins, lipids, hormones, and nucleic acid at the downstream level. The variety of NO acting mechanisms include direct reaction with redox molecule, metal-nitrosation of transient metals, protein tyrosine nitration, and S-nitrosation. Since the discovery of the physiological role of NO in plants, numerous studies have been conducted to elucidate the production pathways, mechanism of action, and its ultimate effect in distinct physiological processes. However, over time, some questions still remain unanswered, and with new knowledge on interactions of NO with fatty acids and nucleic acids, more possible regulatory roles of NO in mitigation of stresses is still under investigation. Therefore, this chapter discusses the NO production, mechanism of action, and role in the regulation of plant’s (a)biotic stress response.
... [221] Their main applications are disinfection of processing utensils, meat and products, cutting boards, and in livestock management, and in latest times, sanitation of water chiefly used for fresh fruit and vegetable washing. [222,223] The use of EW for managing food-borne diseases and the growth of spoilage microbes in processed vegetables were also reported. [224] The harmful effect of EW in combination sodium bicarbonate (1.25%) on inhibition of Penicillium spp. ...
Article
Post-harvest commodities wastage due to decay caused by the pathogenic fungi generates a huge amount of economic losses worldwide. Different species of Penicillium spoil various foodstuffs and produce mycotoxins, alkaloids and other harmful cellular metabolites in the food. Presently, synthetic fungicides, mainly used for fungal diseases control, are associated with harmful impacts on the environment and consumer health. Hence, non-fungicide based eco-friendly and commercially viable alternative is proposed for ensuring food safety. In recent years, the safer options that have been explored include microbe mediated biological control, botanical pesticides, use of generally regarded as safe (GRAS) compounds, and innovative physical approaches including cold plasma, and pulsed light techniques. These emerging technologies could be utilized in the multiple hurdle concept of disease management for suppressing pathogens growth at different stages of spoilage development. This review, first of its kind, summarizes the exclusive information on Penicillium spp. induced spoilage, associated toxicological concerns and the potential of non-fungicide-based promising approaches for managing fungal wastage in the harvested horticultural commodities.
... COD directly measures the oxygen required to oxidize soluble and particulate matters in water. Previous studies have shown that COD increases with increased product loading rate in the same tank of water [6,7]. The measurement of COD is time-consuming (typically two hours), and currently there is no on-line monitoring method available. ...
Article
Full-text available
Organic materials in fresh-cut produce wash water deplete free chlorine that is required to prevent pathogen survival and cross-contamination. This research evaluated water quality parameters frequently used to describe organic load for their fitness to predict chlorine demand (CLD) and chemical oxygen demand (COD), which are major needs identified by the industry-led produce food safety taskforce. Batches of romaine lettuce, iceberg lettuce, or carrot of different cut sizes and shapes were washed in 40 liters of water. Physicochemical properties of wash water including CLD, COD, total organic carbon (TOC), total suspended solids (TSS), total dissolved solids (TDS), turbidity, total sugar content, and pH, were monitored. Results indicate that pH is primarily commodity dependent, while organic load is additionally impacted by cutting and washing conditions. Significant linear increases in COD, TOC, CLD, TDS, and turbidity resulted from increasing product-to-water ratio, and decreasing cut size. Physicochemical parameters, excluding pH, showed significant positive correlation across different cut sizes within a commodity. High correlations were obtained between CLD and COD and between COD and TOC for pooled products. The convenient measurement of TDS, along with its strong correlation with COD and CLD, suggests the potential of TDS for predicting organic load and chlorine reactivity. Finally, the potential application and limitation of the proposed models in practical produce processing procedures are discussed extensively.
... Microbe inactivation was reported to be effective at high current density. This study revealed that combination of high current density, flow rate and doping level will synergistically give a higher rate of microbial inactivation (Gómez-López, Gobet, Selma, Gil, & Allende, 2013). The content of artichoke wastewater and efforts towards their organic content and solids removal has been reported. ...
Article
The serious water scarcity experienced across the globe and the desire for sufficient food production all year round to combat hunger, poverty and malnutrition necessitate the need for wastewater reuse in irrigation. Wastewater has varied compositions that affect the growth of different crops positively, they may also be a source of dangerous pollutant. Heavy consumption of vegetables have been encouraged for its nutritional and health advantages. Hence, their production and cultivation have increased globally. While the nutritional advantage of vegetables is appealing, their high susceptibility to harbor and spread pathogenic microbes call for serious concern. Activities such as transportation, improper handling and packaging amongst others are sources of vegetable contamination. Irrigation water and techniques however present greater danger. Agro-industrial wastewater of a ready-to-eat vegetable (RTEv) industry operating a closed system may reintroduce microbes to vegetable gardens. The use of raw domestic wastewater, either black or grey water in vegetable cultivation presents attendant challenges which must be handled with utmost precaution. This review is focused on the dangers associated with the reuse of agro-industrial and domestic wastewater, precautions required as well as possible preventive/reduction measures. The possible dangers associated with “crude irrigation techniques” used in vegetable cultivation in the Southwestern part of Nigeria are presented. This work will no doubt serve as a tool for policy makers and environmentalists in enlightenment and awareness campaigns in educating most rural dwellers who are ignorant of these dangers.
... Recently, Qi et al. (2018) established that electrolyzed oxidizing (EO) water, as an advanced chlorinebased solution, is superior to regular sodium hypochlorite-based sanitizers in removing pesticide residues from fresh produce. Therefore, given that there are many studies that support its antimicrobial activity on different fruits (Graca et al., 2011;Torlak, 2014;Ding et al., 2015) and vegetables (Ding et al., 2011;Gómez-López et al., 2013;Hao et al., 2015;Mansur and Oh, 2015), it is of great interest to investigate its efficacy in degrading pesticides. ...
Article
Concerns about chemicals and pesticides in food plants have increased dramatically during the last decade. Following stricter legislation and studies about toxicity and human health risks, new ways of reducing toxic residues are urgently required. In this study, oxidizing agents such as electrolyzed water (EW), chlorine dioxide (ClO2) and photocatalysis have been used during the postharvest phase in order to remove the residues of cyprodinil, tebuconazole and iprodione from the surface of peaches, nectarines and apricots. Moreover, the disinfection capability of these agents has also been tested as an alternative to sodium hypochlorite. Our results show that pesticide removal from stone fruits by oxidizing technologies significantly varies depending on the treatment used and the target substance. ClO2 significantly reduced tebuconazole residues from all the fruits (by more than 60%) and photocatalysis similarly reduced iprodione residues (between 50 and 70%). However, EW achieved a percentage of residue reduction similar to that of tap water, never exceeded 40%. In contrast, EW reduced the superficial microbiota to undetectable counts, also decreasing the percentage of rotted fruit from 32 to 7%. Photocatalysis produced similar results since it was able to decrease the microorganisms present on the fruit surface by nearly 2 log units and the incidence of disease by 50%. It was concluded that a strategy combining photocatalysis treatment during cold storage to reduce pesticide residues and spoilage microorganisms with electrolyzed water washing to reduce any remaining microbial contamination prior to commercialization will substantially reduce disease and ensure the safety of stone fruits for human consumption.
... Since 1999, many studies have demonstrated the potential use of EW as sanitizer for washing fresh and minimally processed fruits and vegetables (Koseki and Isobe, 2007;Pangloli et al., 2009;Hung et al., 2010;Pangloli and Hung, 2011;Kim and Hung, 2012). The use of EW in the fresh-cut processing line could represent a good alternative to sodium hypochlorite (López-Gálvez et al., 2012;Gómez-López et al., 2013). ...
... (>1100 mV) is produced at the anode side of the electrolytic cell while basic electrolyzed and with a longer shelf life than AEW ( Hricova et al., 2008), has been used in 65 industrial trials without negative effects on product quality and equipment ( Ongeng et al., 66 2006;Fallanaj et al., 2013). Gómez-López et al., 2013;Fallanaj et al., 2015). Although the efficacy of 113 EW is influenced by several factors such as content of organic matter, pH, temperature, 114 level of agitation and water hardness as recently reviewed by Gil et al. (2015), the Abadias et al., 2008). ...
Article
Full-text available
Washing water used for processing fruits and vegetables can convey spoilage fungi and bacteria. The common procedure to reduce microbial contamination involves the use of chlorine based compounds. Recently, electrolyzed water (EW) has been evaluated as an alternative measure in controlling microbial spoilage contamination occurring during washing steps. This work reviews results related to the application of EW for controlling microbial viability responsible for decay development during storage period. EW produced with sodium bicarbonate as electrolyte reduced Penicillium spp. population in water and, consequently, green mould decay in citrus fruits; the use of sodium chloride in EW production inactivated spores of Fusarium sp. in water and reduced pineapple decay during storage at 12°C for 20 days as well as controlled yeast and mould population in date fruit up to six months of cold storage. EW was also found effective in controlling spoilage bacteria on ready-to-eat produce. Pseudomonas fluorescens, Pantoea agglomerans, and Rhanella aquatilis were undetectable in electrolyzed process water amended with sodium chloride although similar treatment slightly reduced Erwinia carotovora load inoculated onto lettuce. EW at low free chlorine concentration reduced viability of Pseudomonas spp. and psychrotrophic bacteria in both simulated and industrial washing water. EW treatment of fresh cut lettuce dipped in microbial contaminated water reduced Pseudomonas spp. of about 1 log cfu g-1 delaying spoilage symptoms that occurred early in untreated vegetables. These results demonstrate that the use of EW can control spoilage microorganisms in washing water, reduce crosscontamination phenomena and delay fruit and vegetable decay.
... Among the alternatives to sodium hypochlorite, electrolyzed water (EW) has recently become a popular sanitizer in the food chain (Al-Haq et al., 2005;Hricova et al., 2008;Rahman et al., 2016). EW was firstly developed in Russia for water decontamination and regeneration (Nikitin and Vinnik, 1965;Kunina, 1967); then, it gained great interest in Japan, where the technology has been widely studied, and other countries, for sterilization of utensils, meats, cutting boards, and, more recently, in livestock management and for the sanitation of the washing waters of fresh and minimally processed fruit and vegetables (Lee et al., 2004;Ongeng et al., 2006;Fallanaj et al., 2013;Gómez-López et al., 2013). ...
Article
Physical treatments have gained great interest in recent years to control many postharvest diseases in fruits and vegetables because the total absence of residues in the treated product and minimal environmental impact. The present review shows the extensive research work conducted during many years and increased in the last 10 years, developing physical means for consistent disease control. The review include the use of cold storage as the main physical method for delaying or reducing biotic and abiotic diseases. Physical treatments, like heat, including hot water and hot air treatments, radio frequency and microwave, hypobaric and hyperbaric pressure and far ultraviolet radiation (UV-C light), are treated as promising control means, and controlled and modified atmospheres as complementary physical tools essential to reduce or delay the development of postharvest pathogens. A particular emphasis is given to the mode of action, which involve direct effect to the pathogen (lethal or sub-lethal) of spore germination and mycelial growth of fungi and the resistance induction in the host which is not well known but nowadays, with the new tools available in molecular biology will be easy to highlight other physiological and biochemical pathways on which the phenomenon are based. Besides benefits of treatment in different commodities, also limitations of use, including low persistence, risk of adverse effects and technological problems for commercial application are discussed.
... Among the alternatives to sodium hypochlorite, electrolyzed water (EW) has recently become a popular sanitizer in the food chain (Al-Haq et al., 2005;Hricova et al., 2008;Rahman et al., 2016). EW was firstly developed in Russia for water decontamination and regeneration (Nikitin and Vinnik, 1965;Kunina, 1967); then, it gained great interest in Japan, where the technology has been widely studied, and other countries, for sterilization of utensils, meats, cutting boards, and, more recently, in livestock management and for the sanitation of the washing waters of fresh and minimally processed fruit and vegetables (Lee et al., 2004;Ongeng et al., 2006;Fallanaj et al., 2013;Gómez-López et al., 2013). ...
Article
Disinfection of fresh fruit and vegetables after harvest is an essential first step of postharvest handling. The minimal requirement from disinfection procedures is to maintain commodities and facilities free of fungal postharvest pathogens and bacterial human pathogens and thus improve food safety. Disinfection of postharvest pathogens that accumulate on the fruit surface before and during harvest is a direct benefit and in particular cases it can by itself prevent decay after storage. The current review includes historical, chemical, and regulatory background on some of the major disinfectants available for usage today. These include chlorine, chlorine dioxide, ozone, ethanol, hydrogen peroxide, organic acids, and electrolyzed water. Some of the disinfectants described in this review are in wide usage for many years and some are considered ‘alternative’ and are at initial levels of usage. Information is given on experimental reports, practical application, phytotoxicity, residues, advantages, disadvantages and mode of action of the compounds and technologies. Special emphasis is given to vapor and gas phase applications due to their unexploited potential and to some complementary technologies that have been reported in recent years. The conclusion from the many details in this review is that disinfection is an important tool to ensure management of postharvest decay of fresh produce. In some cases, disinfection is a precondition to successful implementation of major postharvest technologies and in particular cases it can become the major technology. An important aspect arising from this review is also that some of the bad reputation of chemical disinfectants is unjustified because they leave no or non-toxic levels of residues and their environmental impact is minor in view of their potential benefits.
... Among the alternatives to sodium hypochlorite, electrolyzed water (EW) has recently become a popular sanitizer in the food chain (Al-Haq et al., 2005;Hricova et al., 2008;Rahman et al., 2016). EW was firstly developed in Russia for water decontamination and regeneration (Nikitin and Vinnik, 1965;Kunina, 1967); then, it gained great interest in Japan, where the technology has been widely studied, and other countries, for sterilization of utensils, meats, cutting boards, and, more recently, in livestock management and for the sanitation of the washing waters of fresh and minimally processed fruit and vegetables (Lee et al., 2004;Ongeng et al., 2006;Fallanaj et al., 2013;Gómez-López et al., 2013). ...
Chapter
Natural products, either as pure compounds or as standardized extracts, provide unlimited opportunities to control microbial growth, owing to their chemical composition and diversity. Many herb and spice extracts possess antimicrobial activity against a range of bacteria, yeast, and moulds. Because of their antimicrobial properties, they could be very useful, either as food preservatives or as natural biopesticides. In particular, extracts from wild edible herbaceous species are rich in phenolic compounds. A wide variety of phenolics derived from herbs and spices possesses potent biological activities contributing to their effect against spoilage microorganisms. Many studies have pointed out the antimicrobial properties of certain classes of phenolic compounds, such as hydroxybenzoic, coumaric, and caffeic acid derivatives, flavonoids and coumarins, catechin, epicatechin, proanthocyanidins, and tannins. Moreover, some authors studied the relationship between molecular structure and antimicrobial activity of some phenolic compounds. The antimicrobial activity of polyphenols is principally due to inhibition of some important cellular functions (nucleic acid synthesis, cytoplasmatic membrane functionality, etc.) and to disruption of membrane integrity with consequent leakage of cellular contents. This chapter reviews the most important phenol-rich wild edible herbaceous species known within the Mediterranean area, highlighting the relationship between phenolic composition and antimicrobial activity of their extracts. Moreover, the problem of standardization and safety of plant extracts is analyzed in the light of the latest literature.
... This issue is expected to become particularly critical in the next years, due to the intensification of the demand for fresh-cut produce in developing countries. The minimization of water use and wastewater discharges are thus big challenges for the fresh-cut industry that will be increasingly required to implement sustainable strategies for water saving ( € Olmez & Kretzschmar, 2009; G omez-L opez, Gobet, Selma, Gil, & Allende, 2013). By focussing on the eco-efficient management of water, new opportunities and technologies for the environmental performance improvement, that can be also cost-effective, are increasingly under study and possibly applicable for water saving in fresh-cut production . ...
Article
Among the different food industries, fresh-cut produce manufacturing is one of the major waterintensive, due to the huge consumption of potable water to perform washing operations required to guarantee the safety and quality of the product. Reducing the water footprint of washing is thus a challenge for fresh-cut industries and food researchers. This review paper examines the current status of the water resource management in the fresh-cut industry and critically describes a comprehensive approach to the improvement of the water use efficiency by implementing strategies of water recirculation, reuse and recycling. In particular, advantages and limitations of chlorine and chlorine-free disinfectants to reduce water turnover in washing tanks were considered. In addition, particular attention was focussed on innovative technological solutions, based on either physical or chemical stresses, which could be exploited individually or in combination to treat wastewater deriving from fresh-cut washing and allow its recycling within the processing plant.
... Electrolytic treatment technology is also another alternative method. Electrochemical oxidation has been applied widely in recent years in industrial wastewater, such as textile industry effluents [13,14], as well as in disinfection of drinking, swimming pool, and seawater [15,16]. In our previous studies, we have conducted experiments on the possibility of using ion-exchange membrane electrolytic methods to treat ballast water [17]. ...
Article
Full-text available
Ships' ballast water can carry aquatic organisms into foreign ecosystems. In our previous studies, a concept using ion exchange membrane electrolysis to treat ballast water has been proven. In addition to other substantial approaches, a new strategy for inactivating algae is proposed based on the developed ballast water treatment system. In the new strategy, the means of multi-trial injection with small doses of electrolytic products is applied for inactivating algae. To demonstrate the performance of the new strategy, contrast experiments between new strategies and routine processes were conducted. Four algae species including Chlorella vulgaris, Platymonas subcordiformis, Prorocentrum micans and Karenia mikimotoi were chosen as samples. The different experimental parameters are studied including the injection times and doses of electrolytic products. Compared with the conventional one trial injection method, mortality rate time (MRT) and available chlorine concentration can be saved up to about 84% and 40%, respectively, under the application of the new strategy. The proposed new approach has great potential in practical ballast water treatment. Furthermore, the strategy is also helpful for deep insight of mechanism of algal tolerance.
... The flocs formed are trained by the gas bubbles to the solution surface to constitute a large foam at the water/air interface. The foam becomes denser with time [24]. As seen in Fig. 2, it appears that EF efficiency is highly dependent on t EF . ...
Article
Full-text available
This study investigates the microalgae removal from Ghrib Dam water by electroflotation (EF) using stainless steel electrodes. The results obtained show that EF is excellent in microalgae removal (~100%). The effects of parameters such as: current density (i), initial pH and distance between electrodes (d) are examined. The optimal conditions are: i = 170 A m−2 and d = 1 cm during 15 min at pH 7.8. Future research must focus on microalgae lysis, toxin release and degradation due to EF treatment. Precautions must be taken such as reducing the applied voltage, increasing the residence time in the electrochemical device and adding a powdered activated carbon adsorption stage.
... Model parameters numerically confirmed such differences, indicating that first and second disinfection rates (k 1 and k 2 ) increased significantly when PAA concentration increased (Table 1). The biphasic model used in the present study has been previously used to fit the bacterial disinfection either by PAA or by electrolyzed water of RW for the freshcut industry where oxidation processes also occurred (G omezL opez, Marín, et al. 2013, G omez-L opez, Gobet, Selma, Gil, & Allende, 2013G omez-L opez, Gil, Allende, Vanhee, et al. submitted for publication;L opez-G alvez et al., 2012). However, this model would be implementable for real situations if sanitizer consumption rate would be considered. ...
... The minimization of water use and wastewater discharges are thus big challenges for the fresh-cut industry. They are nowadays required to identify sustainable technologies to allow water recycling during longer periods ( € Olmez & Kretzschmar, 2009; G omez-L opez, Gobet, Selma, Gil, & Allende, 2013). ...
... Studies indicate that BDD generates important amounts of reactive oxygen species (ROS) together chlorine compounds (Cl 2 , HOCl, and OCl − ) (Gusmão et al., 2010;Martínez-Huitle and Brillas, 2008). The large amounts of ROS such as production of hydroxyl radicals during water electrolysis result in faster bacterial abatement (Gómez-López et al., 2013;Li et al., 2010;Martínez-Huitle and Brillas, 2008). In this respect, some researchers have also pointed out that the disinfecting efficacy of this method is much higher than that of chlorination method because other oxidants are also formed by electrogeneration (López-Gálvez et al., 2012;Martínez-Huitle and Brillas, 2008;Venczel et al., 2004). ...
Article
Inadequate access to clean water and sanitation are the most relevant problems afflicting developing and industrialized nations. Global water scarcity is expected to grow worse in the coming decades and this has motivated the scientific community to identify new, safe, and robust water disinfection technologies at lower cost and with less energy, diminishing the use of chemicals and impact on the environment. Usually, conventional methods of water treatment can solve this problem satisfactorily, such as chlorination, but, sometimes, they can be chemically, energetically, and operationally intensive. Therefore, the science and technology has encouraged the development of other alternative disinfection technologies. In this frame, electrochemical disinfection or electrodisinfection is currently experiencing a renaissance due to the tremendous contributions of novel electrocatalytic materials as well as the use of electric current as an inexpensive and suitable reagent to drive the inactivation of waterborne pathogens, avoiding conventional chemical oxidizers or reducing agents. Electrodisinfection has a significant technical impact, because it can be easily scaled up or design small–portable devices, benefiting from advantages such as versatility, environmental compatibility, automation, inherent safety, and potential cost effectiveness among others. Diamond films emerge as a novel and sustainable solution to electrogenerate powerful oxidants for effectively controlling waterborne pathogens in drinking water. The overarching goal of this critical review is to evidence the importance of diamond electrochemical methods as alternative for the eradication of waterborne infectious agents from public and drinking waters. The mechanisms of bacteria inactivation, and the fundamentals and applications of electrochemical oxidation with diamond to disinfect synthetic and real waters and wastewaters are exhaustively discussed. The use of hybrid and sequential processes involving electrochemical oxidation with other techniques, as well as endodontic and food control applications, are also analyzed. A section remarking the future challenges of electrodisinfection with diamond is finally presented.
Article
The market size of fresh and minimally-processed fruits and vegetables (MPFVs) have grown rapidly in the last years as a result of consumer attitudes change due to their increasing use in prepared mixed salad for fresh, healthy and convenient food. Handling and mechanical operations of cutting and peeling induce injures and release of on-site cellular contents which promote the growth of harmful microbes. Chlorine has been widely adopted in fresh and MPFVs disinfection in washing due to its low cost and high efficacy against a broad spectrum of microorganisms; but, continuous replenishment of chlorine into high organic wash water can promote the formation of suspected carcinogenic compounds. There is a real need to find new alternatives to chlorine to preserve MPFVs quality for longer time. Although several methods and chemicals can be used to achieve similar reduction of microorganism counts without the production of harmful compounds, nor compromising the quality of MPFVs produce, fewer amount of them have gained widespread acceptance by the food industry. The challenge of this work was to give an upgraded level of understanding for producers and retailers to underpin future research directions for a modern food industry in order to resolve existing issues that limit fresh-cut quality and shelf-life. This paper covers a comprehensive review to improve shelf-life and quality of MPFVs, from the traditional technologies toward the most promising advancements.
Chapter
This chapter reviews the implications of water quality in the fresh produce industry and the associated problems from the food safety and environmental perspectives including the wastewater generated. Guidelines and national regulations focused on Good Agricultural Practices (GAP), Good Handling Practices (GHP), and Good Manufacturing Practices (GMP) recommend that water must be of potable quality when contacting the fresh commodity throughout all postharvest operations including washing, cooling, and rinsing. Water may become contaminated during processing and promote cross-contamination among different product lots. Water disinfection is needed to minimize the potential of cross-contamination of process wash water although it does not completely eliminate microbial contamination on a contaminated product. Disinfectant efficacy must be monitored and controlled throughout establishment of critical operational limits for water quality variables ensuring that optimal doses are maintained. A critical water quality variable is the organic matter content as it will directly affect the maintenance of minimum effective doses which should be enough to avoid cross-contamination in process wash water while avoiding accumulation and formation of disinfection by-products (DBPs). Selection of the most adequate disinfectant for each washing system will also have an impact on the DBP. Formation and accumulation of DBPs in process wash water must be avoided to reduce chemical risks but without compromising the maximum degree of protection against microbial risks. Large volumes of water are used in the fresh produce industry directly, impacting the generation of wastewater. The water quality variables of the generated wastewater, mainly influenced by the organic matter content and presence of DBP, and the efficacy of disinfection treatments for water reconditioning will determine the potential reuse of wastewater generated in the fresh produce industry.
Article
Electrochemical disinfection has been shown to be an efficient method with a shortrequired contact time for treatment of drinking water supplies, industrial raw water supplies, liquid foodstuffs, and wastewater effluents. In the present work, the electrochemical disinfection of saline water contaminated with bacteria was investigated in chloride-containing solutions using Sb-doped Sn80%-W20%-oxide anodes. The influence of current density, bacterial load, initial chloride concentration, solution pH, and the type of bacteria (E. coli D21, E. coli O157:H7, and E. faecalis) on disinfection efficacy was systematically examined. The impact of natural organic matter and a radical scavenger on the disinfection process was also examined. The electrochemical system was highly effective in bacterial inactivation for a 0.1 M NaCl solution contaminated with ∼10(7) CFU/mL bacteria by applying a current density ≥1 mA/cm(2) through the cell.100% inactivation of E. coli D21 was achieved with a contact time of less than 60 s and power consumption of 48 Wh/m(3), by applying a current density of 6 mA/cm(2) in a 0.1 M NaCl solution contaminated with ∼10(7) CFU/mL. Reactive chlorine species as well as reactive oxygen species (e.g. hydroxyl radicals) generated in situ during the electrochemical process were determined to be responsible for inactivation of bacteria.
The elimination of total and fecal coliforms, from raw surface water, was carried out by electrochemical oxidation using either boron doped diamond (BDD/Ti) or graphite (GP) anodes, in a chloride-free medium. The optimal values of the operation parameters, maximizing the coliform elimination percentage, were determined using statistical experimental design. The current density ( j: 2-20 mA/cm2), the conductivity (s: 500-900 μS/cm) and the anode materials (An) were considered as variables to perform the Box-Behnken experimental design together with the response surface methodology analysis for optimization. The statistical analysis indicated that, in the evaluated range, the disinfection efficiency increased with an increase in j and decreased with an increase in s. The following optimal conditions for the elimination of total and fecal coliforms were found: j: 10 mA/cm2, s: 500 μS/cm and BDD/Ti used as anode material. The BDD/Ti electrode let to achieve complete coliform elimination after ca. 20 min of reaction while the GP one needed ca. 27 min. In water treated with both BDD/Ti and GP anode, after 7 days, any coliforms growth was observed. As a result of the oxidation process, the total organic carbon and nitrite concentration decreased while nitrate concentration increased.
Chapter
This review examined scientific reports and articles published from 2007 to 2016 regarding the major environmental sources of pathogenic Escherichia coli and the routes by which they enter the human gastrointestinal tract. The literature describes novel techniques used to combat pathogenic E. coli transmitted to humans from livestock and agricultural products, food-contact surfaces in processing environments, and food products themselves. Although prevention before contamination is always the best “intervention,” many studies aim to identify novel chemical, physical, and biological techniques that inactivate or eliminate pathogenic E. coli cells from breeding livestock, growing crops, and manufactured food products. Such intervention strategies target each stage of the food chain from the perspective of “Farm to Table food safety” and aim to manage major reservoirs of pathogenic E. coli throughout the entire process. Issues related to, and recent trends in, food production must address not only the safety of the food itself but also the safety of those who consume it. Thus, research aims to discover new “natural” antimicrobial agents and to develop “multiple hurdle technology” or other novel technologies that preserve food quality. In addition, this review examines the practical application of recent technologies from the perspective of product quality and safety. It provides comprehensive insight into intervention measures used to ensure food safety, specifically those aimed at pathogenic E. coli.
Chapter
In an effort to eat healthfully, consumers have increased their consumption of fruits and vegetables over the past three decades only to find that produce, in spite of its minimal processing and perishability is now almost as frequently implicated as a vehicle of foodborne illness as food of animal origin. It is apparent that produce can be easily contaminated by bacteria, viruses or parasites at any of the many steps from farm to table including: the growing environment (soil, water, fertilizer, agri-chemicals); by workers using poor hygiene; by contact with equipment used in production, harvesting, processing and transportation, as well as at wholesale and retail sale. Salmonella spp. (lettuce, melons, spinach, tomatoes, seed sprouts and spices) and Escherichia coli O157:H7 (lettuce and spinach) are the leading pathogens associated with foodborne illnesses linked to fresh produce, but Listeria (L.) monocytogenes (cantaloupe) and non-O157 Shiga-toxigenic (STEC) E. coli (sprouts) have been implicated in recent deadly outbreaks. Post-harvest washing of fresh produce with chlorine is widely used for sanitizing, but its efficacy is inadequate and its disadvantages are such that alternative disinfection methods including chemical or natural antimicrobial solutions and physical methods are being examined.
Article
Electrolyzed water (EW) is known by its bactericidal efficacy and capability to oxidize organic matter. The present research evaluated the efficacy of recently developed electrolytic cells able to generate higher concentration of reactive oxygen species using lower power and salt concentration than conventional cells. This study tested the inactivation of Escherichia coli O157:H7, the organic matter depletion and trihalomethane (THM) generation by EW in process wash water under dynamic conditions. To achieve this, clean tap water was continuously added up to 60 min with artificial process water with high chemical oxygen demand (COD) inoculated with E. coli O157:H7, in experiments performed in a pilot plant that recirculated water through one electrolytic cell. Plate counts of E. coli O157:H7, COD, THMs, free, combined and total chlorine, pH, temperature and oxidation-reduction potential were determined. Results indicate that the novel electrolysis system combined with minimal addition of NaCl (0.05%) was able to suppress E. coli O157:H7 population build-up and decreased the COD accumulation in the process wash water. THM levels in the water were relatively high but its concentration in the washed product was marginal. Highly effective electrolysis has been proven to reduce the occurrence of foodborne diseases associated to cross-contamination in produce washers without having an accumulation of THMs in the washed product.
Article
Full-text available
Disinfection of hot water systems is critical in reducing the incidence of disease outbreaks caused by pathogenic bacteria. Electrochemical disinfection (ED) has been identified as an economical, low-maintenance, and chemical-free alternative in the fight against waterborne pathogenic microorganisms. It also provides the residual disinfection needed to inactivate the planktonic bacteria released by the biofilm. The work presented here includes fundamental small-scale laboratory optimization experiments in a flask where platinum-coated electrodes were immersed in 3.5 L of tap water contaminated with Escherichia coli (NCT10418) with an initial population density between 3×105 and 1.6×105 colony forming units/mL (CFU/mL) or Legionella pneumophila serogroup 1 (NCTC12821) ranging from 180 to 244 CFU/mL. Voltage, electrode area, interelectrode distance, spiking time, volume of contaminated water, and mixer speed were varied to determine the optimal geometrical and operational requirements needed to kill bacteria. Experimental results indicate ED to be an effective control method, with a >4-log inactivation of E. coli and a >5-log inactivation of Legionella in 10 and 45 min, respectively, at a current density of ≈4 mA/cm2. The findings of the flask experiments were translated into real-world conditions by evaluating the long-term performance of an optimized ED prototype device installed in the hot water recirculation system of a small-size healthcare center building. The results showed that ED is effective at minimizing pathogen contamination of the hot water distribution system from initial values, with total bacteria levels and Pseudomonas species being reduced in all of the samples over a 15-month period following activation of the ED device.
Chapter
This chapter summarizes the conventional and emerging techniques for the fresh-cut industry to maintain quality and guarantee the safety of plant-derived commodities to satisfy consumer demand. The main spoilage changes that affect minimally processed fresh fruit and vegetables (MPFVs) and how the processing techniques solve these problems are reviewed. Alternative technologies that provide fresh-like quality and safe products by means of screening of materials entering the chain, reducing microbial loads and growth, and using synergistic combinations of mild treatments are addressed. These include novel modified atmosphere packaging, disinfection alternatives, antibrowning technologies, and processing operations such as pulsed electric field and the high hydrostatic pressure used for maintaining the overall quality of MPFV and juices.
Data
The suitability of high power ultrasound (HPU, 20 kHz, 0.28 kW/l) combined with residual chemical sanitizers for water reconditioning was studied. A synergetic disinfection effect was observed when HPU was combined with peroxyacetic acid (PAA) or a commercial mix of organic acids and phenolic compounds (OA/PC). In recycled water (RW) with a chemical oxygen demand (COD) of 500 mg O-2/l, PAA inactivated 2 log units of Escherichia coli 0157:H7 at concentrations of 3.2, 6.4, 16 mg/l after 7 min, 2 min, 29 s, respectively. The OA/PC or HPU treatments alone needed 26 min treatments to achieve the same reduction. The addition of TiO2 (5 g/l) to HPU (sonocatalysis) did not improve E. coli 0157:H7 inactivation. However, when HPU was combined with a residual concentration of PAA (3.2 mg/l), the total inactivation of E. colt 0157:H7 and Salmonella (6 log unit reductions) occurred after 11 min, but for Listeria monocytogenes only 1.7 log reductions were detected after 20 min. When HPU was combined with OA/PC, a synergistic effect for the inactivation of E. coli 0157:H7 was also observed, but this sanitizer significantly modified the physical-chemical quality characteristics of the RW. These results show that the residual PM concentration that can be found in the wash water combined with HPU could result in an environmentally friendlier and toxicologically safer strategy for water reconditioning of the fresh-cut industry. The use of the sanitizer alone requires higher concentrations and/or longer contacts times. Even though the residual PM in combination with HPU was adequate for water reconditioning, it is not appropriate for the process wash water because this wash water must be instantaneously disinfected.
Chapter
Full-text available
Recommendations for a balanced diet include consumption of fresh fruit and vegetables as an important part of the diet of people around the world. Consumers increasingly perceive fresh food as healthier than heat-treated food, which motivates a general search for new minimally fresh processed fruit and vegetables. However, despite the benefits derived from eating fresh foods, safety is still an issue of concern owing to a wide range of documented cases of contaminated fresh fruits and vegetables, which have caused large outbreaks of microbial infections. Minimally fresh processed fruit and vegetables are very perishable products, highly susceptible to deterioration, and minimal processing reduced shelf life leading to additional quality losses. Therefore, the derived processed produces are in fact more sensitive to disorders than the original ones. Many factors affect the shelf-life and microbial quality of raw prepared fruit and vegetables, and include good agricultural practices, good hygienic practices during harvesting and handling, quality of washing water, processing technologies, packaging methods and materials, and processing, storage, transportation, distribution and retail sale temperatures. Common practices consist of the protection of the produce from damage caused by poor handling or machinery, foreign body contamination, and/or pest infestation.
Chapter
The minimal processing to which minimally processed fruits and vegetables (MPFV) are subjected makes products highly perishable, requiring refrigerated conditions during storage to guarantee a reasonable shelf life. The processing steps included in minimal processing steps such as peeling or cutting remove the natural protection of fruits and vegetables, promoting microbial growth as well as physical and physiological changes which reduce both the quality and shelf life of the product. Additionally, the processing steps included in the minimal processing can represent a source of spoilage and pathogenic contamination. In fact, one of the major concerns of MPFV is that none of the steps included in the processing chain will guarantee the inactivation of pathogenic bacteria. Unless numerous studies have been carried out to evaluate the capacity of different sanitizing agents or disinfection techniques for inactivating pathogenic bacteria, their efficacy is still much reduced. Therefore, prevention is the only way to avoid contamination of the product. On the other hand, the optimization of the processing steps to minimize the negative consequences of wounding in MPFV will increase shelf life and maintain the appearance and the nutritional and flavor quality of these products.
Article
Full-text available
The efficacy of thin-film diamond coated electrodes (DiaCell® 101) for disinfection of water artificially contaminated with Penicillium digitatum and Pseudomonas spp. was tested. Electrolysis process was performed with different operation conditions: current densities set at 4, 8, and 12A and water flow rate at 150, 300, and 600 L/h. For both pathogens, the experiments were performed in water suspensions at a final concentration of 105 CFU/ml. Tap water was used as a control. The results showed that fungal spores and bacterial cells were affected by flow rate and current density applied. The higher the water flow rate the greater the inactivation of the two microorganisms which were completely suppressed at high recirculation flow (300-600 L/h/cell). Pseudomonas spp. cells were inactivated at the highest current density applied (8-12A) after 6 min of electrolysis, whereas for P. digitatum the complete inactivation was observed at the same current densities after 12 min. The results obtained suggest that the two parameters can be modulated in order to achieve significant suppression in relation to the target microorganism and to obtain an antimicrobial effect without generation of chlorine.
Article
The suitability of high power ultrasound (HPU, 20 kHz, 0.28 kW/l) combined with residual chemical sanitizers for water reconditioning was studied. A synergetic disinfection effect was observed when HPU was combined with peroxyacetic acid (PAA) or a commercial mix of organic acids and phenolic compounds (OA/PC). In recycled water (RW) with a chemical oxygen demand (COD) of 500 mg O2/l, PAA inactivated 2 log units of Escherichia coli O157:H7 at concentrations of 3.2, 6.4, 16 mg/l after 7 min, 2 min, 29 s, respectively. The OA/PC or HPU treatments alone needed 26 min treatments to achieve the same reduction. The addition of TiO2 (5 g/l) to HPU (sonocatalysis) did not improve E. coli O157:H7 inactivation. However, when HPU was combined with a residual concentration of PAA (3.2 mg/l), the total inactivation of E. coli O157:H7 and Salmonella (6 log unit reductions) occurred after 11 min, but for Listeria monocytogenes only 1.7 log reductions were detected after 20 min. When HPU was combined with OA/PC, a synergistic effect for the inactivation of E. coli O157:H7 was also observed, but this sanitizer significantly modified the physical-chemical quality characteristics of the RW. These results show that the residual PAA concentration that can be found in the wash water combined with HPU could result in an environmentally friendlier and toxicologically safer strategy for water reconditioning of the fresh-cut industry. The use of the sanitizer alone requires higher concentrations and/or longer contacts times. Even though the residual PAA in combination with HPU was adequate for water reconditioning, it is not appropriate for the process wash water because this wash water must be instantaneously disinfected.
Article
Full-text available
Purpose of the review: Fresh cut produce continues to be implicated in foodborne illness outbreaks with the principle pathogens being norovirus, Escherichia coli O157:H7, Salmonella, Listeria monocytogenes and enteric protozoan. There has been a strong reliance on post-harvest washing to remove field acquired contamination and has been the subject of intensive research over the last 15 years. This review focuses on recent advances in the efficacy of different approaches to inactivate, remove or minimize cross-contamination of human pathogens associated with post-harvest fresh produce. Findings: Post-harvest washing only achieves a negligible reduction in human pathogen levels but can significantly increase the potential of cross-contamination between batches. Consequently recent advances in produce washing have focused on reducing crosscontamination events through stabilizing sanitizers (ie, chlorine) in the presence of high organic loading to retain residual antimicrobial activity (organic acids). Alternative interventions such as electrochemical oxidation are directed at decontaminating wash water as opposed to inactivating pathogens directly on produce. More successful produce decontamination technologies are not based on washing but rather on sanitizers applied in the gas phase or physical techniques such as gas plasma, UV and E-beams. Directions for future research: With the limitations of aqueous-based washing it can be envisaged that a post-wash intervention step will be implemented for controlling human pathogens associated with fresh produce. Transferring technologies from the laboratory to commercial processing will be challenging and the focus of future research.
Article
Chemical sanitizers are routinely used during commercial flume washing of fresh-cut leafy greens to minimize cross-contamination from the water. This study assessed the efficacy of three chlorine treatments against Escherichia coli O157:H7 on iceberg lettuce, in wash water, and on surfaces of a pilot-scale processing line using flume water containing various organic loads. Iceberg lettuce (5.4 kg) was inoculated to contain 10⁶ CFU/g of a 4-strain cocktail of nontoxigenic, green fluorescent protein–labeled, ampicillin-resistant E. coli O157:H7 and held for 24 h at 4°C before processing. Lettuce was shredded using a Urschel TransSlicer, step conveyed to a flume tank, washed for 90 s using water alone or one of three different sanitizing treatments (50 ppm of total chlorine either alone or acidified to pH 6.5 with citric acid or T-128) in water containing organic loads of 0, 2.5, 5, or 10% (wt/vol) blended iceberg lettuce, and then dried using a shaker table and centrifugal dryer. Next, three 5.4-kg batches of uninoculated iceberg lettuce were processed identically. Various product (25 g), water (50 ml), and equipment surface swab (100 cm²) samples were homogenized in neutralizing buffer, diluted appropriately, and plated on tryptic soy agar containing 0.6% (wt/vol) yeast extract and 100 ppm of ampicillin without prior 0.45- m m membrane filtration to quantify E. coli O157:H7. Organic load negatively impacted the efficacy of all three chlorine treatments (P E. coli O157:H7 reductions of >5 and 0.9 to 3.7 log CFU/ml for organic loads of 0 and 10%, respectively. Organic load rarely had a significant impact (P E. coli O157:H7 on iceberg lettuce. Reduced sanitizer efficacy generally corresponded to changes in total solids, chemical oxygen demand, turbidity, and maximum filterable volume, indicating that these tests may be effective alternatives to the industry standard of oxygen/reduction potential.
Article
Electrochemical (EC) residual disinfection of Escherichia coli (E. coli) in the presence and absence of primary sludge particulates (PSPs) was studied. The kinetics followed a first-order rate law. When PSPs were absent, the EC residual disinfection rate coefficient (k) increased linearly with EC pretreatment energy (EC, 0-0.63 kWh/m(3)). However, with 143 mg PSPs/L, k first increased linearly with EC (0-0.28 kWh/m(3)) and then decreased linearly with EC (0.28-0.42 kWh/m(3)). H2O2 was detected during EC pretreatment in PSPs-free samples and the H2O2 concentration (CH) increased with EC (0-0.83 kWh/m(3)) linearly. Chloride was detected in PSPs aqueous samples (143 mg PSPs/L) and its concentration (CC) changed during EC pretreatment: initially, a decrease of CC was observed when EC increased from 0 to 0.28 kWh/m(3), followed by an increase of CC when EC increased 0.28-0.42 kWh/m(3). In both cases, k correlated to the initial post-EC chloride concentration (CCI) in an inverse linear relationship. This two-stage change of CC and k was caused by a combination of two reactions: anodic oxidation of chloride and the reaction of chloramines with excess chlorine. This paper explains the mechanisms underlying EC residual disinfection in the presence and absence of PSPs, and proposes a feasible strategy for EC disinfection when PSPs are present, an approach that could be useful in the treatment of combined sewage overflow (CSO).
Article
Full-text available
The aim of this work was to investigate the disinfectant effect of electrolysis on chlorine-free water, artificially contaminated with Escherichia coli (CCT-1457) and to evaluate the bactericidal activity of electrolysis and kinetic behavior of a single-cell reactor, with a DSA (Dimensionally Stable Anode) electrode to develop a scaled-up system. A high-density E. coli suspension (10(6) CFU mL(-1)) was electrolyzed in this reactor at 25, 50 and 75 mA cm(-2) for up to 60 min, at flow rates of 200 and 500 L h(-1). Bacterial survival fell by 98.9% without addition of chlorinated compounds and a power consumption rate not more than 5.60 kWh m(-3) at flow rate of 200 L h(-1) and 75 mA cm(-2). The process produced a germicidal effect that reached this inactivation rate within a relatively short contact time. Also, a solution of electrolyzed 0.08 M Na2SO4 added to the inoculum showed residual bactericidal effect. The efficiency of disinfection was regulated by both the contact time and current density applied, and a kinetic function for the survival rate was developed for the purpose of scaling up.
Data
Full-text available
Chemical water treatment problems such as disinfection by-products formation have urged on the search of better water treatment technologies such as electrochemical water technologies which have been applied successfully in different water/wastewater pollutant removal. However, their wide extension is hindered by some technical problems such as chlorine by-products (CBPs) generated species. Indeed, during electrochemical process, these carcinogenic substances may be formed depending on the electrode material and applied voltage. This review concerns the dependence of CBPs generated species formation of the electrode material and applied charge during electrochemical water treatment. It is concluded that the use of electrodes producing highly reactive species must be more carefully controlled in hygienically and environmentally oriented applications. From this point of view, Pt and boron-doped diamond (BDD) anodes are proved more convenient than other electrodes. Indeed, the great capability of a BDD anode to produce reactive oxygen species and other oxidising species during the electrolysis allows establishing a chlorine-free disinfection process.
Article
Full-text available
Washing is a critical step for maintaining quality and safety of fresh-cut produce during its preparation and is often the only measure taken to reduce microbial populations and remove tissue fluids. However, little is known about the effect of washing method on water quality or its consequence on microbial growth and finished product quality. This study was conducted to evaluate the effect of wash water reuse on changes in water quality and its subsequent effect on microbial growth and product quality of packaged fresh-cut Romaine lettuce (Lactuca sativa L.). Romaine lettuce leaves were sliced and washed in water with chemical oxygen demand levels ranging from 9.8 mg.L(-1) (fresh water) to 1860.5 mg.L(-1) (reused water) and product-to-water ratios of 1:20 and 1:150. The washed samples were dried and placed into packages prepared from films with an oxygen transmission rate of 8.0 pmol.s(-1).m(-2).Pa(-1) and stored at 5 degrees C for 14 days. Microbial growth and product quality were monitored at days 0, 4, 8, 11, and 14 during storage. Results indicate that as the quantity of lettuce dipped in 40 L of water increased from 2.0 kg to 18.0 kg, water chemical oxygen demand increased from 124 mg.L(-1) to 1721 mg.L(-1) and biological oxygen demand increased from 140 mg.L(-1) to 526 mg.L(-1), whereas free and total chlorine levels declined from 151.5 mg.L(-1) to 4.7 mg.L(-1) and from 171 mg.L(-1) to 31.5 mg.L(-1), respectively. Thoroughly washed lettuce in clean water with a small product-to-water ratio had the least off-odor development. Samples without wash treatment and those washed with reused water had 0.8 to 1.6 log cfu.g(-1) higher populations of lactic acid bacteria than those washed with clean water at the end of storage.
Article
The efficacy of gaseous and liquid ClO2 or neutral electrolysed water (NEW) to decontaminate minimally processed vegetables, without affecting sensory quality, was evaluated using aerobic plate counts and triangle tests. Gaseous ClO2 yielded >1 log cfu/g reduction in lettuce and cabbage. but caused browning. Aqueous ClO2 did not reduce aerobic plate count of lettuce and cabbage, but yielded >1 log reduction in carrots. Lettuce was sensorially affected by ClO2 washings, but cabbage and carrots were not. NEW yielded >1 log reduction in lettuce, cabbage and carrots; a 5 min treatment did not damage their sensory quality. Aqueous ClO2 was most appropriate to decontaminate carrots and NEW for lettuce, cabbage, and carrots. Gaseous ClO2 was effective in decreasing lettuce and cabbage microbial load but significantly affected their sensory quality.
Article
Electrochemical disinfection in chloride-free electrolyte has attracted more and more attention due to advantages of no production of disinfection byproducts (DBPs), and boron-doped diamond (BDD) anode with several unique properties has shown great potential in this field. In this study, inactivation of Escherichia coli (E. coli) was investigated in Na2SO4 electrolyte using BDD anode. Firstly, disinfection tests were carried on at different current density. The inactivation rate of E. coli and also the concentration of hydroxyl radical (OH) increased with the current density, which indicated the major role of OH in the disinfection process. At 20mAcm−2 the energy consumption was the lowest to reach an equal inactivation. Moreover, it was found that inactivation rate of E. coli rose with the increasing Na2SO4 concentration and they were inactivated more faster in Na2SO4 than in NaH2PO4 or NaNO3 electrolyte even in the presence of OH scavenger, which could be attributed to the oxidants produced in the electrolysis of SO42−, such as peroxodisulfate (S2O82−). And the role of S2O82− was proved in the disinfection experiments. These results demonstrated that, besides hydroxyl radical and its consecutive products, oxidants produced in SO42− electrolysis at BDD anode played a role in electrochemical disinfection in Na2SO4 electrolyte.
Article
Acidic electrolyzed water (acidic EW), which is prepared by the electrolysis of an aqueous NaCl solution, has recently become of great importance for disinfection in a variety of fields, including medicine, the food industry and agriculture. In a previous paper we showed that: 1) acidic EW is a mixture of hypocholorite ion, hypochlorous acid and chlorine, depending upon the pH; 2) hypochlorous acid is primarily responsible for disinfection in the case of Escherichia coli K12 and Bacillus subtilis PCI219, both in clean culture media. In practice, however, the use of acidic EW is in many cases severely hampered due to the presence of a variety of non-selective reducing agents. In view of the salient nature of acidic EW, it is therefore strongly urged to establish an optimum way to use acidic EW in a variety of systems. The present paper is the first report on our attempt along this line in order to characterize the nature of the chemical changes that the bactericidal activity of the acidic EW deteriorates in the presence of organic materials, which include amino acids and proteins.
Article
The primary method to eliminate, or significantly reduce, pathogens on produce is strict adherence to Good Agricultural Practices (GAPs), Good Manufacturing Practices (GMPs), Hazard Analysis Critical Control Points (HACCP), and other relevant strategies that prevent contamination from occurring. This includes the concept of "good management practices" as described in the Guide to Minimize Microbial Food Safety Hazards for Fresh Fruits and Vegetables (FDA 1998). Although the frequency of produce contamination by pathogens is thought to be very small, there are no known mitigation strategies that will completely remove pathogens after contamination has occurred while maintaining produce freshness. A variety of mitigation regimens and sanitizers are available to reduce microbial populations depending upon the type of produce involved. Washing and sanitizing efficiencies depend on several factors, including characteristics of the produce surface, water quality, cleaner/sanitizer used, contact time, and presence and type of scrubbing action. Based on reported data, it is likely that different sanitation mitigation strategies are needed for different produce items.
Article
Chemical water treatment problems such as disinfection by-products formation have urged on the search of better water treatment technologies such as electrochemical water technologies which have been applied successfully in different water/wastewater pollutant removal. However, their wide extension is hindered by some technical problems such as chlorine by-products (CBPs) generated species. Indeed, during electrochemical process, these carcinogenic substances may be formed depending on the electrode material and applied voltage. This review concerns the dependence of CBPs generated species formation of the electrode material and applied charge during electrochemical water treatment. It is concluded that the use of electrodes producing highly reactive species must be more carefully controlled in hygienically and environmentally oriented applications. From this point of view, Pt and boron-doped diamond (BDD) anodes are proved more convenient than other electrodes. Indeed, the great capability of a BDD anode to produce reactive oxygen species and other oxidising species during the electrolysis allows establishing a chlorine-free disinfection process.Research Highlights► At [Cl−] < 100 mg L–1, free Cl2(g) can be produced with the risk of DBPs formation. ► Electric field conditions must be optimised to avoid DBPs formation. ► The DBPs formed can be removed by passing through activated carbon.
Article
In this work the products of the oxidation at BDD anode of chloride ions in aqueous solutions were identified during galvanostatic electrolyses performed in a filter-press reactor operating both in batch and continuous mode. A set of experiments were preformed in order to study the effect of operating conditions (current density, residence time, hydrodynamics and chloride concentration) on distribution and concentration of electrolysis by-products. As a comparison experiments were also performed using a commercial DSA anode. A simple mathematical model was formulated, and the model predictions agree with the experimental data in a wide range of experimental conditions. The results of this work showed that at low chloride concentrations electrolysis with BDD anode produce a mixture of powerful oxidant: low current density, high mass transfer conditions and low residence time were found as optimal conditions to maximize the concentration of oxidants and minimize the concentration of chlorates. The proposed reaction mechanism may also justify the controversial effect of chloride ions in wastewater treatments: the electrolysis carried out with BDD anodes and electrolyte containing chloride concentration higher 1g/L could meet the target of the process only if the active chlorine is effective in oxidation of the pollutant that must be removed.
Article
The electrochemical mineralization of organic pollutants is a new technology for treatment of dilute wastewater (COD< 5gL−1). In this method, use of the electrical energy can produce complete oxidation of pollutants on high oxidation power anodes. An ideal anode for this type of treatment is a boron-doped diamond electrode (BDD) characterized by a high reactivity towards oxidation of organics. In the present work kinetic aspects of organic mineralization is discussed. The proposed theoretical kinetic model on boron-doped diamond anodes is in excellent agreement with experimental results. In addition economic aspects of electrochemical organic mineralization are reported.
Article
The sanitization efficacy of slightly acidic electrolyzed water (SAEW) against food pathogens on selected fresh ready-to-eat (RTE) vegetables and sprouts was evaluated and compared to sodium hypochlorite (NaOCl) solution. RTE vegetables and sprouts were dip-inoculated with Escherichia coli (E. coli) and Salmonella spp. and dip-treated with SAEW, NaOCl solution for 5 min. SAEW treatment significantly (p < 0.05) reduced the total aerobic mesophilic bacteria from Chinese celery, lettuce and daikon sprouts by 2.7, 2.5 and 2.45 log10CFU/g, respectively relative to un-treated. Pathogens were significantly (p < 0.05) reduced from Chinese celery, lettuce and daikon sprouts by 2.7, 2.8 and 2.8 log10CFU/g (E. coli) and 2.87, 2.91 and 2.91 log10CFU/g (Salmonella spp.), respectively following a SAEW treatment. SAEW and NaOCl solution showed no significant sanitization difference (p > 0.05). Results demonstrate that SAEW at low chlorine concentration and a near neutral pH is a potential non-thermal food sanitizer that could represent an alternative to NaOCl solution and would reduce the amount of free chlorine used in fresh-cut vegetables industry, since the same microbial reduction as NaOCl solution is obtained.
Article
Increasing concerns about the possible formation of carcinogenic compounds and the emergence of new, more tolerant pathogens, have raised questions on the use of chlorine in fresh-cut produce. There is a growing need to investigate the efficacy of new commercial sanitizing and other alternative technologies. In the present study, the effectiveness of chlorine and other commercial sanitizer agents (Sanova, Sanoxol 20, Tsunami 100, Purac FCC 80, Citrox 14W and Catallix) was evaluated on epiphytic microorganisms and their influence on the sensory quality of fresh-cut escarole and lettuce. Different sanitizer concentrations (manufacturer's recommended dose and half of this dose) and application systems (submersion and spray) were also compared. The antimicrobial efficacy of the treatments was evaluated, initially after washing, and after 8 days of storage simulating a commercial shelf-life (3 days at 4 °C + 5 days at 8 °C). All the tested washing solutions were more effective in reducing the microbial load than water washes, particularly in fresh-cut escarole. However, the microbial load of fresh-cut escarole and lettuce after 8 days of storage was very similar for most of the treatments despite the different application systems and concentrations of the sanitizers. Clearly epiphytic microorganisms of fresh-cut escarole and lettuce were able to grow rapidly during storage under low temperature, reaching similar or higher values than the unwashed fresh-cut produce at the day of production. The overall visual quality of fresh-cut salad leaves was scored as good or very good (≥6) after 8 days of storage, except for the product washed with Purac. Thus, despite the high number of mesophilic bacteria present in the product, between 6 and 8 log cfu g−1, it was not associated with a detrimental quality. Therefore, the determination of the initial epiphytic reductions of fresh-cut products after washing with different sanitizing agents provides little information about the microbial or sensory quality of the product at the time of consumption.
Article
Disinfection is one of the most important processing steps affecting the quality and safety and the shelf-life of the end product in fresh-cut processing. Chlorine is the most widely used disinfectant in fresh-cut industry. However, recent outbreaks associated with pathogen contamination in fresh-cut vegetables raised the concerns about the efficacy of chlorine treatment in assuring the safety of the products. Moreover, due to the environmental and health risks posed by the use of chlorine, there is a trend in eliminating chlorine from the disinfection process. Thus, there is a need for alternative sanitizers to be used for the disinfection of fresh-cut vegetables, not only for the organic food sector but also for the conventional food processors. Another challenge for the food industry is the minimization of water consumption and wastewater discharge rates. The United Nations Environment Programme stated that Europe is one of the two global regions where more water is used for industry than for agriculture. Among the different industries, the food industry ranks third in water consumption and wastewater discharge rates coming after the chemical and refinery industries. The adoption of less water consuming systems is required for improved water management in the industry. Therefore the food industry is now seeking alternatives to chlorine which assure the safety of the products, maintain the quality and shelf-life, while also reducing the water consumption rates in processing. Chlorine dioxide, ozone, organic acids, peroxyacetic acid, electrolyzed oxidizing water and hydrogen peroxide are the main alternative sanitizing agents that gained interest in recent years. The effects of these disinfecting agents on the microbiological, nutritional and sensory quality of fresh-cut produce, and also the possible environmental impact and the potential on minimizing water consumption rates in the food industry are reviewed in this manuscript.
Article
The efficacy of an electrochemical treatment in water disinfection, using boron-doped diamond electrodes, was studied and its suitability for the fresh-cut produce industry analyzed. Tap water (TW), and tap water supplemented with NaCl (NaClW) containing different levels of organic matter (Chemical Oxygen Demand (COD) around 60, 300, 550 ± 50 and 750 ± 50 mg/L) obtained from lettuce, were inoculated with a cocktail of Escherichia coli O157:H7 at 10⁵ cfu/mL. Changes in levels of E. coli O157:H7, free, combined and total chlorine, pH, oxidation-reduction potential, COD and temperature were monitored during the treatments. In NaClW, free chlorine was produced more rapidly than in TW and, as a consequence, reductions of 5 log units of E. coli O157:H7 were achieved faster (0.17, 4, 15 and 24 min for water with 60, 300, 500 and 750 mg/L of COD, respectively) than in TW alone (0.9, 25, 60 min and 90 min for water with 60, 300, 600 and 800 mg/L of COD, respectively). Nonetheless, the equipment showed potential for water disinfection and organic matter reduction even without adding NaCl. Additionally, different mathematical models were assessed to account for microbial inactivation curves obtained from the electrochemical treatments.
Article
This study was conducted to investigate the effect of free chlorine concentrations in wash water on Escherichia coli O157:H7 reduction, survival, and transference during washing of fresh-cut lettuce. The effectiveness of rewashing for inactivation of E. coli O157:H7 on newly cross-contaminated produce previously washed with solutions containing an insufficient amount of chlorine also was assessed. Results indicate that solutions containing a minimum of 0.5 mg/liter free chlorine were effective for inactivating E. coli O157:H7 in suspension to below the detection level. However, the presence of 1 mg/liter free chlorine in the wash solution before washing was insufficient to prevent E. coli O157:H7 survival and transfer during washing because the introduction of cut lettuce to the wash system quickly depleted the free chlorine. Although no E. coli O157:H7 was detected in the wash solution containing 5 mg/liter free chlorine before washing a mix of inoculated and uninoculated lettuce, low numbers of E. coli O157:H7 cells were detected on uninoculated lettuce in four of the seven experimental trials. When the prewash free chlorine concentration was increased to 10 mg/liter or greater, no E. coli O157:H7 transfer was detected. Furthermore, although rewashing newly cross-contaminated lettuce in 50 mg/liter free chlorine for 30 s significantly reduced (P = 0.002) the E. coli O157:H7 populations, it failed to eliminate E. coli O157:H7 on lettuce. This finding suggests that rewashing is not an effective way to correct for process failure, and maintaining a sufficient free chlorine concentration in the wash solution is critical for preventing pathogen cross-contamination.
Article
Direct (non-mediated) electrochemical oxidation of ammonia on boron-doped diamond (BDD) electrode proceeds mainly at high pH (> 8) via free ammonia (NH3) oxidation. To enhance ammonia oxidation on BDD at low pH (< 8), where mainly ammonium (NH4+) is present, oxidation of ammonia was mediated by active free chlorine. In this process, electro-generated in situ active chlorine rapidly reacts with ammonia instead of being further electro-oxidized to chlorate at the electrode surface. Thus, active chlorine effectively removes ammonia from an acidic solution, while the formation of by-products such as chlorate and possibly perchlorate is minimized.
Article
Chlorine dioxide (ClO(2)) has been postulated as an alternative to sodium hypochlorite (NaClO) for fresh-cut produce sanitization to avoid risks associated with chlorination by-products. Experiments were performed to determine the prevention of cross-contamination of fresh-cut lettuce by Escherichia coli using chlorine dioxide (3 mg/L) or sodium hypochlorite (100 mg/L) as sanitation agents. The efficacy of these sanitation solutions was evaluated simulating as much as possible the conditions of a fresh-cut processing line. Thus, to evaluate the potential risk of cross-contamination during pre-washing, inoculated fresh-cut lettuce was pre-washed and after that non-inoculated lettuce was then pre-washed in the same water. After this pre-washing, non-inoculated lettuce was cross-contaminated, changing from 0 to 3.4 log units of E. coli cells. During washing with sanitizers, none of the tested sanitation agents significantly reduced E. coli counts in both inoculated and cross-contaminated lettuce. These results suggest that when cross-contamination occurs, even if the event is recent, subsequent sanitation steps are inefficient for inactivating E. coli cells on the vegetable tissue. However, chlorine dioxide and sodium hypochlorite solutions were able to inactivate most E. coli cells that passed from inoculated product to wash water. Therefore, they might be able to avoid cross-contamination between clean and contaminated product during the washing step. Scanning electron microscopy micrographs indicated that bacterial cells were mainly located in clusters or tissue stomata where they might be protected, which explains the low efficacy of sodium hypochlorite and chlorine dioxide solutions observed in this study.
Article
A study was conducted to demonstrate direct and mediated anodic processes for the oxidation of organic pollutants. The study proposed different expressions of current efficiency, such as instantaneous current efficiency (ICE), electrochemical oxidation index (EOI), general current efficiency (GCE), and mineralization current efficiency (MCE). ICE of electro-oxidation was determined by the oxygen flow rate (OFR) method or chemical oxygen demand (COD). GCE represented an average value of current efficiency between the initial time t = 0 and t. Efforts were made to perform electrolysis at a high anodic potential in the region of water discharge, using intermediates of electrogenerated hydroxyl radicals. Another strategy involved oxidizing pollutants by indirect electrolysis, generating a redox reagent in situ as a chemical reactant.
Article
It is well known that fresh-cut processors usually rely on wash water sanitizers to reduce microbial counts in order to maintain quality and extend shelf-life of the end product. Water is a useful tool for reducing potential contamination but it can also transfer pathogenic microorganisms. Washing with sanitizers is important in fresh-cut produce hygiene, particularly removing soil and debris, but especially in water disinfection to avoid cross-contamination between clean and contaminated product. Most of the sanitizing solutions induce higher microbial reduction after washing when compared to water washing, but after storage, epiphytic microorganisms grow rapidly, reaching similar levels. In fact, despite the general idea that sanitizers are used to reduce the microbial population on the produce, their main effect is maintaining the microbial quality of the water. The use of potable water instead of water containing chemical disinfection agents for washing fresh-cut vegetables is being advocated in some European countries. However, the problems of using an inadequate sanitizer or even none are considered in this manuscript. The need for a standardized approach to evaluate and compare the efficiency of sanitizing agents is also presented. Most new alternative techniques accentuate the problems with chlorine suggesting that the industry should move away from this traditional disinfection agent. However, the use of chlorine based sanitizers are presented as belonging to the most effective and efficient sanitizers when adequate doses are used. In this review improvements in water disinfection and sanitation strategies, including a shower pre-washing step and a final rinse of the produce, are suggested.
Article
Electrochemical disinfection has gained increasing attention as an alternative for conventional drinking water treatment due to its high effectiveness and environmental compatibility. The most common method of electrochemical disinfection is the use of electro-generated oxidants, such as active chlorine and reactive oxygen species, as disinfectants. This study examined the role of electrode material on the generation of oxidants, and elucidated the different reaction pathways for generating individual oxidants by employing boron-doped diamond (BDD), Ti/RuO(2), Ti/IrO(2), Ti/Pt-IrO(2), and Pt as anode materials. The efficiency of ()OH production, as determined by para-chlorobenzoic acid (pCBA) degradation, was in the order of BDD>Ti/RuO(2) approximately Pt. No significant production of ()OH was observed at Ti/IrO(2) and Ti/Pt-IrO(2). The ()OH was found to play a key role in O(3) generation at BDD, but not at the other electrodes. The production of active chlorine was in the order of Ti/IrO(2)>Ti/RuO(2)>Ti/Pt-IrO(2)>BDD>Pt. The large difference in this order from that of ROS was attributed to the difference in the electrocatalytic activity of each electrode material toward the production of active chlorine, as evidenced by linear sweep voltammetry (LSV) measurements. In addition, the characteristics of microbial inactivation as a function of electrode material were examined under the presence of an inert electrolyte, using Escherichia coli as an indicator microorganism.
Article
This study was undertaken to evaluate the efficacy of electrolyzed oxidizing (EO) and chemically modified water with properties similar to the EO water for inactivation of different types of foodborne pathogens (Escherichia coli O157:H7, Listeria monocytogenes and Bacillus cereus). A five-strain cocktail of each microorganism was exposed to deionized water (control), EO water and chemically modified water. To evaluate the effect of individual properties (pH, oxidation-reduction potential (ORP) and residual chlorine) of treatment solutions on microbial inactivation, iron was added to reduce ORP readings and neutralizing buffer was added to neutralize chlorine. Inactivation of E. coli O157:H7 occurred within 30 s after application of JAW EO water with 10 mg/l residual chlorine and chemically modified solutions containing 13 mg/l residual chlorine. Inactivation of Gram-positive and -negative microorganisms occurred within 10 s after application of ROX EO water with 56 mg/l residual chlorine and chemically modified solutions containing 60 mg/l residual chlorine. B. cereus was more resistant to the treatments than E. coli O157:H7 and L. monocytogenes and only 3 log10 reductions were achieved after 10 s of ROX EO water treatment. B. cereus spores were the most resistant pathogen. However, more than 3 log10 reductions were achieved with 120-s EO water treatment.
Article
To identify the primary component responsible in electrolyzed oxidizing (EO) water for inactivation, this study determined the concentrations of hypochlorous acid (HOCl) and hypochlorite ions (OCl-) and related those concentrations to the microbicidal activity of the water. The ultraviolet absorption spectra were used to determine the concentrations of HOCl and OCl- in EO water and the chemical equilibrium of these species with change in pH and amperage. EO water generated at higher amperage contained a higher chlorine concentration. The maximum concentration of HOCl was observed around pH 4 where the maximum log reduction (2.3 log10 CFU/ml) of Bacillus cereus F4431/73 vegetative cells also occurred. The high correlation (r = 0.95) between HOCl concentrations and bactericidal effectiveness of EO water supports HOCl's role as the primary inactivation agent. Caution should be taken with standard titrimetric methods for measurement of chlorine as they cannot differentiate the levels of HOCl present in EO water of varying pHs.
Article
This contribution focuses on the presentation of GInaFiT (Geeraerd and Van Impe Inactivation Model Fitting Tool), a freeware Add-in for Microsoft Excel aiming at bridging the gap between people developing predictive modelling approaches and end-users in the food industry not familiar with or not disposing over advanced non-linear regression analysis tools. More precisely, the tool is useful for testing nine different types of microbial survival models on user-specific experimental data relating the evolution of the microbial population with time. As such, the authors believe to cover all known survivor curve shapes for vegetative bacterial cells. The nine model types are: (i) classical log-linear curves, (ii) curves displaying a so-called shoulder before a log-linear decrease is apparent, (iii) curves displaying a so-called tail after a log-linear decrease, (iv) survival curves displaying both shoulder and tailing behaviour, (v) concave curves, (vi) convex curves, (vii) convex/concave curves followed by tailing, (viii) biphasic inactivation kinetics, and (ix) biphasic inactivation kinetics preceded by a shoulder. Next to the obtained parameter values, the following statistical measures are automatically reported: standard errors of the parameter values, the Sum of Squared Errors, the Mean Sum of Squared Errors and its Root, the R(2) and the adjusted R(2). The tool can help the end-user to communicate the performance of food preservation processes in terms of the number of log cycles of reduction rather than the classical D-value and is downloadable via the KULeuven/BioTeC-homepage at the topic "Downloads" (Version 1.4, Release date April 2005).
Article
Chlorination is the most common method worldwide for the disinfection of drinking water. However, the identification of potentially toxic products from this method has encouraged the development of alternative disinfection technologies. Among them, electrochemical disinfection has emerged as one of the more feasible alternatives to chlorination. This article reviews electrochemical systems that can contribute to drinking water disinfection and underscores the efficiency of recently developed diamond films in chlorine-free electrochemical systems.
Direct and mediated electrochemical oxidation of ammonia on boron-doped diamond electrode Efficacy of electrolyzed oxidizing (EO) and chemically modified water on different types of foodborne pathogens
  • A Kapalka
  • L Joss
  • A Anglada
  • C Comninellis
  • K M Udert
Kapalka, A., Joss, L., Anglada, A., Comninellis, C., & Udert, K. M. (2010). Direct and mediated electrochemical oxidation of ammonia on boron-doped diamond electrode. Electrochemistry Communications, 12, 1714e1717. Kim, C., Hung, Y.-C., & Brackett, R. E. (2000). Efficacy of electrolyzed oxidizing (EO) and chemically modified water on different types of foodborne pathogens. International Journal of Food Microbiology, 61, 199e207.
Electrochemical treatment of fresh-cut produce process water using boron-doped diamond electrodes: efficacy for inactivation of Escherichia coli O157:H7 and reduction of chemical oxygen demand
  • F López-Gálvez
  • G D Posada-Izquierdo
  • M V Selma
  • F Pérez-Rodríguez
  • J Gobet
  • M I Gil
López-Gálvez, F., Posada-Izquierdo, G. D., Selma, M. V., Pérez-Rodríguez, F., Gobet, J., Gil, M. I., et al. (2012). Electrochemical treatment of fresh-cut produce process water using boron-doped diamond electrodes: efficacy for inactivation of Escherichia coli O157:H7 and reduction of chemical oxygen demand. Food Microbiology, 30, 146e156.
Determination of free chlorine concentrations needed to prevent Escherichia coli O157:H7 cross-contamination during fresh-cut produce wash
  • Y Luo
  • X Nou
  • Y Yang
  • I Alleger
  • E Turner
  • H Feng
Luo, Y., Nou, X., Yang, Y., Alleger, I., Turner, E., Feng, H., et al. (2011). Determination of free chlorine concentrations needed to prevent Escherichia coli O157:H7 cross-contamination during fresh-cut produce wash. Journal of Food Protection, 74, 352e358.
Methods to reduce/eliminate pathogens from fresh and fresh-cut produce. Comprehensive Reviews in Food Science and Food Safety, 2, 161e173
  • M Panizza
  • G Cerisola
  • M E Parish
  • L R Beuchat
  • T V Suslow
  • L J Harris
  • E H Garrett
  • J N Farber
Panizza, M., & Cerisola, G. (2009). Direct and mediated anodic oxidation of organic pollutants. Chemical Reviews, 109, 6541e6569. Parish, M. E., Beuchat, L. R., Suslow, T. V., Harris, L. J., Garrett, E. H., Farber, J. N., et al. (2003). Methods to reduce/eliminate pathogens from fresh and fresh-cut produce. Comprehensive Reviews in Food Science and Food Safety, 2, 161e173. Polcaro, A. M., Vacca, A., Mascia, M., Palmas, S., & Rodiguez, J. (2009).