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Use of Acidic Electrolyzed Water Ice for Preserving the Quality of Shrimp

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Use of Acidic Electrolyzed Water Ice for Preserving the Quality of Shrimp

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Abstract

Electrolyzed water ice is a relatively new concept developed in food industry in recent years. The effect of acidic electrolyzed water (AEW) ice on preserving the quality of shrimp (Litopenaeus vannamei) was investigated. Physical, chemical and microbiological changes of the shrimp were examined during the storage. The results showed that compared with tap water (TW) ice, AEW ice displayed a potential ability in limiting the pH changes of shrimp flesh, significantly (p<0.05) retarded the changes of color difference and the formation of total volatile basic nitrogen (TVBN). And AEW ice treatment had no adverse effects on the firmness of shrimp. Conventional plate count enumeration and PCR-DGGE demonstrated that AEW ice had a capability to inhibit growth of bacteria on raw shrimp, and the maximum reductions of population reached at >1.0 log CFU/g (>90%) at the 6th day. Moreover, AEW ice was clearly more efficient in maintaining the initial attachments between muscle fibers in shrimp according to histological section analysis. Based on above analysis, AEW ice can be a new alternative of traditional sanitizer to better preserve the quality of seafood in the future.

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... However, bacteria usually cannot be inactivated and remain alive in food. Once aquatic products are exposed to appropriate conditions before consumption, the bacteria can multiply rapidly and cause food spoilage (Lin et al., 2013). Therefore, it is of profound significance to explore new methods to keep the quality of shrimp during storage. ...
... The bacteria in shrimp was counted by plating method (Lin et al., 2013). Briefly, 10 g of shrimps were mixed with 90 mL of saline solution (0.86 %), and then homogenized for 2 min in a filtered bag. ...
... The pH of shrimp was determined by the method of Lin et al. (2013) with some modifications. Briefly, 5 g of shrimp were added to 45 mL saline solution (0.86 %), and then homogenized for 3 min at room temperature. ...
Article
A new protein complex (SAKP-Cur) was successfully prepared by combining soluble Antarctic krill protein with curcumin through hydrophobic action. The potency of photodynamic inactivation (PDI) mediated by the complex on preserving the storage quality of shrimp at 4 °C was investigated by microbiological, chemical, physical and histological methods. Results showed that the SAKP-Cur significantly improved the stability of curcumin, and greatly inactivated the native bacteria in shrimp driven by PDI. Meanwhile, the complex-mediated PDI effectively reduced the endogenous enzyme activity, the production of total volatile basic nitrogen (TVB-N) and malondialdehyde (MDA) in shrimp. Moreover, it obviously maintained the integrity and elasticity of the muscle fibers, thereby reducing the loss of water in myofibrils. Notably, the SAKP-Cur enhanced the PDI potency to preserve the freshness of shrimp during 4 °C storage or freeze–thaw cycles treatment. Therefore, the SAKP-Cur coupled with PDI is an effective fresh-keeping technology for aquatic products.
... AEW is a novel nonthermal bactericidal technology and has less adverse impact on human body as well as the environment (Huang, Hung, Hsu, Huang, & Hwang, 2008;Katayose, Yoshida, Achiwa, & Eguchi, 2007). AEW ice is a new kind of bactericide for preservation or cold sterilization in recent years (Lin et al., 2013). It not only has the advantage of tap water ice but also the potential to be bactericidal. ...
... Phuvasate & Su (2010) studied the efficacy of electrolyzed water ice in reducing histamine-producing bacteria on fish skin. It is believed that AEW ice has the potential use of keeping the freshness of products through inactivating bacteria (Lin et al., 2013;Wang et al., 2014;Xie et al., 2012b). Therefore, it is of great importance to comprehend the physicochemical properties and bactericidal efficiency of AEW ice which contribute to the application of AEW ice in food storage. ...
... The obtained AEW ice was crushed using a hammer before use, and the approximate dimension of the crushed ices was 2.0 cm  1.5 cm  1.0 cm. AEW ice was poured into a sterile stainless steel tray with 2 blocks (72  48  9.5 cm) and stored for 10 h under open conditions at air conditioning ambient temperature of 22 ± 1 C (Lin et al., 2013). The crushed ices were sampled randomly from the remaining stored ice, and pH, ACC, and ORP of AEW ice were measured every 2 h after the AEW ices melted completely in a sealed bag in a 70 C water bath. ...
... Additionally, our group demonstrated that AEW ice had the potential use for keeping the freshness of shrimp by investigating the microbiological, physical, and chemical changes. The results indicated that AEW ice could remarkably inhibit the proliferation of bacteria, changes of pH and color difference, and the formation of TVB-N (Xie, Sun, Pan, & Zhao, 2012;Lin et al., 2013;Wang et al., 2014). ...
... Based on above analysis, it can be concluded that previous studies mainly focused on evaluating the effect of AEW ice on aquatic products preservation via measuring the microbiological (total viable count), physical (texture, color difference, etc.) and chemical (pH, TVB-N, TBA, etc.) changes (Kim et al., 2006;Phuvasate & Su, 2010;Lin et al., 2013;Wang et al., 2014). However, quality indices based on biochemical properties have received little attention for investigating the quality changes of aquatic products with AEW ice treatment during storage. ...
... Electrophoresis was conducted at 60 V for 16 h under a constant temperature (60°C). The DGGE gels was stained with SYBR green I and visualized under UV light (Lin et al., 2013). All determinations were carried out in duplicate. ...
... Total volatile basic nitrogen (TVB-N) was measured according to Lin et al. (2013). Oyster (10.0 ± 0.2 g) was homogenized with 40 mL 0.85% physiological saline solution for 5 min. ...
... The tissue sections of 7 μm were acquired by the RM2235 microtome (Leica Microsystems CMS GmbH, Wetzlar, Germany), and then hematoxylineosin stained routinely. All samples were observed and photographed by an optical RM2235 microscope (Lin et al., 2013). All experiments were conducted at least in triplicates. ...
... Lopez-Caballero et al. (2000) reported that the denaturation of myofibrillar fraction induced the increase of hardness, which led to aggregation and water loss during initial storage. However, as the temperature increasing, microbial growth and oxidation promotion accelerated the protein and lipid degradation rate of food, resulting in myofilament degradation and costameres distraction, thereby inducing the softening of muscle tissue and the decrease of hardness (Cheng et al., 2014;Lin et al., 2013). These facts greatly explained why the samples at 4 • C had a slightly changed hardness, but those at 10 • C and 25 • C presented an obviously decreased one. ...
Article
Photodynamic inactivation (PDI) is a promising method with multiple targets to inactivate bacteria on food using visible light. Inactivation potency of the curcumin-mediated blue light-emitting diode (LED) PDI against the pathogen Vibrio parahaemolyticus on cooked oysters and its effects on the storage quality were investigated by the microbiological, physical, chemical and histological methods during storage at 4 °C, 10 °C and 25 °C. Results showed that the PDI treatment obviously inhibited the recovery of V. parahaemolyticus on oysters during storage, and the maximal difference attained >1.0 Log10 CFU/g (> 90%) compared to control stored at 10 °C and 25 °C. Meanwhile, it displayed a potent ability (p < 0.05) to restrain the decrease of pH values, reduce the production of total volatile basic nitrogen (TVB-N), suppress the lipids oxidation, as well as retard the changes of color difference of the oysters. In addition, the PDI effectively maintained the integrity and initial attachments of muscle fibers, and hence decreased the loss of water in myofibrillar space and the texture softening of oysters during storage. On this basis, this study facilitates the understanding of the potency of bacterial inactivation and food preservation of PDI, and hence pave the way for its application in food industry.
... Total volatile basic nitrogen (TVB-N): TVB-N was determined using the method of Lin et al. (2013). Briefly, the above homogenate (10.0 mL) was mixed with 1.0 g magnesia (MgO; Macklin Biotech Co., Ltd., Shanghai, China). ...
... As the storage period increased, the bacterial counts were quickly elevated enough to degrade the salmon proteins and produce alkaline compounds (e.g., ammonia compounds and trimethylamine), especially at the higher temperature (25 ℃) (Wang et al., 2017;Sun et al., 2019). The autolytic processes mediated by endogenous enzymes are also involved in the production of volatile bases (Lin et al., 2013). All these factors collectively contributed to the observed increase in pH. ...
... The unique fatty fibres and proteins of salmon meet the demand of consumers for the freshness and chewiness of fish. However, microbial growth and oxidation promotion accelerated the degradation of proteins and lipids in fish flesh, resulting in myofilament degradation and costamere distraction (Lin et al., 2013), which led to softening of muscle tissue and decrease in chewiness (Li et al., 2018;Offer and Knight, 1988). In this study, curcumin-mediated PDI potently inactivated the bacteria on the salmon, greatly decelerated protein degradation and effectively retarded lipid oxidation ( Fig. 3A-B, G-H). ...
Article
The effect of curcumin-mediated blue light-emitting diode (LED) photodynamic inactivation (PDI) for preserving the quality of salmon contaminated with Listeria monocytogenes was investigated by microbiological, physical, chemical and histological methods during sample storage at 4 ℃ and 25 ℃. The results showed that PDI decelerated the proliferation of L. monocytogenes on salmon during storage at 25 ℃, with the maximum inhibition reaching 4.0 log10 CFU/g (99.99%), compared to the negative control. Moreover, PDI greatly retarded the increase in pH (P < 0.05) and the production of TVB-N, retarded the accumulation of free fatty acids, and decelerated the degradation of proteins, ultimately preserving the high nutritional value of the salmon. In addition, PDI effectively prevented a change in colour and retarded the loss of water from the salmon, thereby conserving its texture and sensory properties. Therefore, PDI is a promising and valid non-thermal technology to use for fish preservation.
... 1,2 Having a less adverse effect on human health and the environment are important advantages of AEW technology. 3,4 AEW technology can be divided into two major types based on their state: AEW 2,5 and AEW ice. 3,6 AEW technology possesses strong abilities in inactivating pathogens from food, e.g. ...
... 3,4 AEW technology can be divided into two major types based on their state: AEW 2,5 and AEW ice. 3,6 AEW technology possesses strong abilities in inactivating pathogens from food, e.g. Listeria monocytogenes, Eschericahi coli O157:H7, Bacillus cereus, Vibrio parahaemolyticus and Salmonella species among others. ...
... Listeria monocytogenes, Eschericahi coli O157:H7, Bacillus cereus, Vibrio parahaemolyticus and Salmonella species among others. 2,3 In addition, Zhou et al. showed the effect of AEW on quality of Nanhui peaches and elucidated that AEW possessed ability of reducing colour changes of Nanhui peaches during storage. 7 Jia et al. showed that AEW is a beneficial inhibitor for the prevention of enzymatic browning of Chinese yam. ...
Article
Background: Browning frequently occurs at fruits, vegetables and aquatic products during storage, it drastically reduces the consumer's acceptability and considerable financial loss. The objective of this paper was to investigate the effects of acidic electrolyzed water (AEW) technology on polyphenoloxidase (PPO), which is an essential enzyme for browning. Results: AEW ice exhibited a good ability in delaying browning in shrimp. Kinetic study revealed that AEW exhibited the mixed type inhibition of PPO with Ki value of 1.96 mmol L(-1) . Moreover, both Circular dichroism spectrum and Fourier transform infrared spectroscopy analyses revealed that α-helix in PPO decreased whereas random coil increased which indicates that PPO conformation was destroyed. Conclusion: Thus, this paper may provide a deeper understanding of the application of AEW technology for preventing browning in food industry.
... Electrophoresis was conducted at 100 V for 10 h under a constant temperature (60 • C). The DGGE gels were stained with SYBR green I and visualized under UV light (Lin et al., 2013). All determinations were carried out in duplicate. ...
... Furthermore, the muscle tissues of untreated, HHP treated and AEW-HHP treated shrimp samples were compared by microscopic histological analysis. The change of muscle tissue has been demonstrated as an important index for sensory quality of food (Lin et al., 2013;Wang et al., 2015). The results showed that AEW-HHP treatment has no impact on the muscle tissue of shrimp when compared with the untreated and HHP treated groups. ...
Article
Full-text available
Acidic electrolyzed water (AEW), a novel non-thermal sterilization technology, is widely used in the food industry. In this study, we firstly investigated the effect of AEW as a new pressure transmitting medium for high hydrostatic pressure (AEW-HHP) processing on microorganisms inactivation on shelled fresh shrimp. The optimal conditions of AEW-HHP for Vibrio parahaemolyticus inactivation on sterile shelled fresh shrimp were obtained using response surface methodology: NaCl concentration to electrolysis 1.5 g/L, treatment pressure 400 MPa, treatment time 10 min. Under the optimal conditions mentioned above, AEW dramatically enhanced the efficiency of HHP for inactivating V. parahaemolyticus and Listeria monocytogenes on artificially contaminated shelled fresh shrimp, and the log reductions were up to 6.08 and 5.71 log10 CFU/g respectively, while the common HHP could only inactivate the two pathogens up to 4.74 and 4.31 log10 CFU/g respectively. Meanwhile, scanning electron microscopy (SEM) showed the same phenomenon. For the naturally contaminated shelled fresh shrimp, AEW-HHP could also significantly reduce the micro flora when examined using plate count and PCR-DGGE. There were also no significant changes, histologically, in the muscle tissues of shrimps undergoing the AEW-HHP treatment. In summary, using AEW as a new transmitting medium for HHP processing is an innovative non thermal technology for improving the food safety of shrimp and other aquatic products.
... [30] Another study suggest that NEW that contains lower ACC (60 ppm) can be applied on lettuce for disinfectant without interfering the quality of lettuce. [85] Yet in a study that investigate the antimicrobial efficacy of SAEW on mung bean showed that longer treatment time (15 min) can result lowered germination percentage after treatment. [36] However, future studies to focus on the investigation on the quality and nutrition value of various vegetables after application of EW. ...
... [31] Application of AEW ice on shrimp has demonstrated the potential ability in minimizing pH changes of shrimp flesh and significantly retarding the change of color, and it posed no adverse effect on the firmness of shrimp while had a capability to inhibit foodborne pathogen in shrimp. [85] However, there is insufficient studies investigate the effect of EW on seafood and fish quality hence more investigation should conducted. ...
... The raw shrimp results showed that AEW ice, besides its bactericidal effect on TVC, inhibited the pH changes, the formation of total volatile basic nitrogen (TVB-N), and the activity of Polyphenol oxidase (PPO) after 6 days of storage. These results in agreement with Lin et al. (2013) [228] indicate that AEW ice can serve as an innovative method to retain the quality of shrimps. In addition, lower TVB-N, trimethylamine (TMA), and thiobarbituric acid reactive substance (TBARS) values also reported for raw puffer fish (Takifugu obscurus) stored at 4 • C after treatment with weakly acidic EW (WAEW) and modified atmosphere packaging (MAP) [229]. ...
... The raw shrimp results showed that AEW ice, besides its bactericidal effect on TVC, inhibited the pH changes, the formation of total volatile basic nitrogen (TVB-N), and the activity of Polyphenol oxidase (PPO) after 6 days of storage. These results in agreement with Lin et al. (2013) [228] indicate that AEW ice can serve as an innovative method to retain the quality of shrimps. In addition, lower TVB-N, trimethylamine (TMA), and thiobarbituric acid reactive substance (TBARS) values also reported for raw puffer fish (Takifugu obscurus) stored at 4 • C after treatment with weakly acidic EW (WAEW) and modified atmosphere packaging (MAP) [229]. ...
Article
Full-text available
A literature search and systematic review were conducted to present and discuss the most recent research studies for the past twenty years on the application of non-thermal methods for ensuring the microbiological safety and quality of fish and seafood. This review presents the principles and reveals the potential benefits of high hydrostatic pressure processing (HHP), ultrasounds (US), non-thermal atmospheric plasma (NTAP), pulsed electric fields (PEF), and electrolyzed water (EW) as alternative methods to conventional heat treatments. Some of these methods have already been adopted by the seafood industry, while others show promising results in inactivating microbial contaminants or spoilage bacteria from solid or liquid seafood products without affecting the biochemical or sensory quality. The main applications and mechanisms of action for each emerging technology are being discussed. Each of these technologies has a specific mode of microbial inactivation and a specific range of use. Thus, their knowledge is important to design a practical application plan focusing on producing safer, qualitative seafood products with added value following today’s consumers’ needs.
... E.O. water efficacy rapidly decreases when it reacts with organic matter (Al-Holy and Rasco 2015 In addition, many studies have shown that E.O. ice helps seafood products to maintain quality. Research projects conducted on the effects of E.O. ice on seafood quality such as Pacific saury (Kim et al. 2006), shrimps (Lin et al. 2013;Wang et al. 2014Wang et al. , 2015Zhang et al. 2015) investigated not only microbiological changes but also ????, bacterial reduction being more than 4 log CFU/per unit; ???, between 2 and 4 CFU/per unit; ??, bacterial reduction being between 1 and 2 CFU/per unit; bacterial reduction being ?, bacterial reduction being less than 1 log CFU/per unit. -, not measured. ...
... Inhibiting the formation of TVBN and TMAO with E.O. ice will improve the sensory quality of seafoods. Furthermore, E.O. ice with physicochemical properties pH 2.5, ORP 1124 mV, and ACC 26 ppm (Lin et al. 2013;Wang et al. 2014) significantly retarded the formation of TVBN and colour changes in shrimps during 6 days storage. The diversity of bacteria revealed by the polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) method reduced significantly in the shrimp that were stored with E.O. ice in both studies. ...
Article
Electrolysed oxidising water (E.O. water) is produced by electrolysis of sodium chloride to yield primarily chlorine based oxidising products. At neutral pH this results in hypochlorous acid in the un-protonated form which has the greatest oxidising potential and ability to penetrate microbial cell walls to disrupt the cell membranes. E.O. water has been shown to be an effective method to reduce microbial contamination on food processing surfaces. The efficacy of E.O. water against pathogenic bacteria such as Listeria monocytogenes, Escherichia coli and Vibrio parahaemolyticus has also been extensively confirmed in growth studies of bacteria in culture where the sanitising agent can have direct contact with the bacteria. However it can only lower, but not eliminate, bacteria on processed seafoods. More research is required to understand and optimise the impacts of E.O. pre-treatment sanitation processes on subsequent microbial growth, shelf life, sensory and safety outcomes for packaged seafood products.
... Ali et al. (2015) and Xia et al. (2009) reported that the changes in meat redness and yellowness could be related to metmyoglobin formation as an indication of protein oxidation. The VBN value is thus an important indicator of meat decay, and 20 mg N/ 100 g meat muscle was proposed as the highest acceptable level (Lin et al., 2013). In the present study, the VBN value was below this value in all samples, indicating that a high standard of freshness was met with these methods. ...
Article
Quality characteristics of frozen cylindrical pork loin were evaluated following different tempering methods: 27.12 MHz curved-electrode radio frequency (RF) at 1000 and 1500 W, and forced-air convection (FC) or water immersion (WI) at 4°C and 20°C. The developed RF tempering system with the newly designed curved-electrode achieved relatively uniform tempering compared to a parallel-plate RF system. FC tempering at 4°C was the most time-consuming process, whereas 1500 W RF was the shortest. Pork sample drip loss, water holding capacity, color, and microbiological quality declined after WI tempering at 20°C. Conversely, RF tempering yielded minimal sample changes in drip loss, microstructure, color, and total aerobic bacteria counts, along with relatively uniform internal sample temperature distributions compared to those of the other tempering treatments. These results indicate that curved-electrode RF tempering could be used to provide rapid defrosting with minimal quality deterioration of cylindrical frozen meat block products.
... EO water has been considered as an effective alternative to antimicrobial based treatment used in the food industry (Hsu, 2003). It has been widely used to control pathogens on fresh fruits and vegetables (Forghani & Oh, 2013;Guentzel, Lam, Callan, Emmons, & Dunham, 2010;Hung, Tilly, & Kim, 2010;Pangloli, Hung, Beuchat, King, & Zha, 2009;Park, Alexander, Taylor, Costa, & Kang, 2008Stopforth, Mai, Kottapalli, & Samadpour, 2008;Udompijitkul, Daeschel, & Zhao, 2007;Zhang et al., 2011), meat (Fabrizio & Cutter, 2004Rahman, Park, Song, Al-Harbi, & Oh, 2012), eggs (Bialka, Demirci, Knabel, Patterson, & Puri, 2004;Cao, Zhu, Shi, Wang, & Li, 2009;Park, Hung, Lin, & Brackett, 2005;Russell, 2003) and seafood (Lin et al., 2013;Ren & Su, 2006). EO water has been demonstrated to have strong disinfectant activity against wide range of pathogens. ...
... Bacteria were counted according to the procedure described in a previous study [35] with some modifications. Briefly, the culture was serially diluted 10-fold in 0.85 % NaCl solution, and then 0.1 mL samples of each dilution were spread onto the thiosulfate citrate bile sucrose agar (TCBS, Beijing Land Bridge Technology Company Ltd., Beijing, PRC) plate. ...
Article
Full-text available
Background Vibrio parahaemolyticus is a main causative agent of serious human seafood-borne gastroenteritis disease. Many researchers have investigated its pathogenesis by observing the alteration of its virulence factors in different conditions. It was previously known that culture conditions will influence the gene expression and the metabolic profile of V. parahaemolyticus, but little attention has been paid on the relationship between them. In this study, for the first time, the metabolomics response in relation to the expression of two major virulence genes, tdh and trh, induced at three temperatures (4, 25 and 37 °C) was examined in two genotypes of pathogenic Vibrio parahaemolyticus (ATCC33846 (tdh+/trh−/tlh+) and ATCC17802 (tdh−/trh+/tlh+)). Results Reverse transcription real-time PCR (RT-qPCR) analysis illustrated that the expression levels of tdh and trh induced at 25 °C in V. parahaemolyticus were significantly higher than those induced at 4 and 37 °C. Principal components analysis (PCA) based on the UPLC & Q-TOF MS data presented clearly distinct groups among the samples treated by different temperatures. Metabolic profiling demonstrated that 179 of 1,033 kinds of identified metabolites in ATCC33846 changed significantly (p <0.01) upon culturing at different temperatures, meanwhile 101 of 930 kinds of metabolites changed (p <0.01) in ATCC17802. Pearson’s correlation analysis highlighted the correlation between metabolites and virulence gene expression levels. At the threshold of | r | = 1, p <0.01, 12 kinds of metabolites showed extremely significant correlations with tdh expression, and 4 kinds of metabolites significantly correlated with trh expression. It is interesting that 3D, 7D, 11D-Phytanic acid showed the same trend with pyrophosphate, whose derivative could activate the degradation of phytanic acid. Several metabolites could be sorted into the same class by the method of chemical taxonomy, by assuming that they are involved in the same metabolic pathways. Conclusions This research can help to find biomarkers to monitor virulence gene expression, and can further help laboratory and clinical research of V. parahaemolyticus from the perspective of metabolomics. Electronic supplementary material The online version of this article (doi:10.1186/s12866-016-0688-5) contains supplementary material, which is available to authorized users.
... Although an increased understanding has been achieved in recent years concerning the softening in postmortem shrimp muscle (Qian, Xie, Yang, & Wu, 2013;Navarrete-del-Toro, García-Carreño, Hernández-Cortés, Molnár, & Gráf, 2015;Okpala, 2015;Annamalai et al., 2015;Nunak & Schleining, 2011;Lin et al., 2013), few studies have focused on the behavior of proteolytic enzymes during storage. Investigations on the softening of muscle demonstrated a protease mediated activity on muscle tissue during storage Chen, Guttmann, Xiong, Webster, & Romaire, 2008;Garcia-Carreno, Hernandez-Cortes, & Haard, 1994;Brauer et al., 2003;Ezquerra, García-carreño, & Haard, 1997;Sriket et al., 2012b;Lu, Liu, & Tsai, 1990;Sriket, Benjakul, Visessanguan, & Kishimura, 2011). ...
Article
Fluorescein-isothiocyanate (FITC) labeled trypsin-like protease was prepared and injected into the hepatopancreas of white shrimp. Different segments of the injected shrimp were analyzed with a fluorescence microscope during storage. FITC-trypsin-like protease can be detected in the first segment of shrimp muscle at day 4, while it cannot be observed in the second segment until day 6. The results showed that trypsin-like protease can migrate from hepatopancreas to the tail portion. Texture profile analysis showed that soybean trypsin inhibitor retarded the softening of the shrimp muscle. The rheological results revealed that the content of myosin heavy chain (MHC) in shrimp muscle was decreased with the extended storage time. Proteomics analysis displayed that trypsin-like protease accelerated the metabolism of postmortem muscle. It can be concluded that trypsin-like protease migrated from the hepatopancreas to the muscle tissue, degraded myofibrillar protein, deteriorated the muscle texture, and eventually leaded to the softening of white shrimp.
... The influence of electrolyzed water on the sensory properties of RTE foods has not been studied. The influence of EO water on some of the sensory attributes such as color, odor, firmness, and texture on raw chicken (Rahman, Park, Song, Al-Harbi, & Oh, 2012), pork (Rahman, Wang, & Oh, 2013) and shrimp (Lin et al., 2013) was studied. Rahman et al. (2012), reported that the fresh chicken breast which was treated by EO water, showed better sensory score after 7 days storage at 4 C compared to the sample which was not treated by EO water. ...
... The mortality rate due to listeriosis is about 20-30 % in vulnerable groups (Kathariou 2002;Embarek 1994). Shrimp is one of the most important aquatic products in South and Southeastern parts of Asia, as well as one of the most popular foods in these areas because of the delicacy and nutrition (Amagliani et al. 2012;Xu et al. 2013;Lin et al. 2013). Therefore, rapid, accurate, and efficient quantitative detection methods for these two pathogens in shrimp would be of great value to the seafood industry and for improving public health. ...
Article
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A novel TaqMan-based multiplex real-time PCR method combined with propidium monoazide (PMA) treatment was firstly developed for the simultaneous quantification of viable Vibrio parahaemolyticus and Listeria monocytogenes in raw shrimp. The optimization of PMA concentration showed that 100 μM was considered optimal to effectively inhibit 10(8) CFU/mL dead cells of both bacteria. The high specificity of this method was confirmed on tests using 96 target and non-target strains. The optimized assay could detect as low as 10(1)-10(2) CFU/g of each strain on the artificially contaminated shrimp, and its amplification efficiencies were up to 100 and 106 % for V. parahaemolyticus and L. monocytogenes, respectively. Furthermore, this assay has been successfully applied to describe the behavior of these two pathogens in raw shrimps stored at 4 °C. In conclusion, this PMA TaqMan-based multiplex real-time PCR technique, where the whole procedure takes less than 5 h, provides an effective and rapid tool for monitoring contamination of viable V. parahaemolyticus and L. monocytogenes in seafood, improving seafood safety and protecting public health.
... Salmonella is the second major foodborne pathogen in china, and the prevalence of Salmonella contamination in seafood samples was 20.8% (Yan et al., 2010). As one of the most important seafoods, shrimp has been in great demand throughout the world because of their delicacy (Lin, Wang, & Zhao, 2013). Consumption of shrimp contaminated with Salmonella might cause a severe public health problem (Amagliani et al., 2012). ...
Article
Propidium monoazide (PMA) combined with molecular quantitative real-time PCR (qPCR) has been widely used for only detection of viable bacteria. However, recent studies indicated PMA did not fully inhibit the detection of dead Salmonella. In this study, we developed a more effective PMA Taqman-based qPCR than previous studies to quantify viable Salmonella spp. in raw shrimp. This method has high specificity by using 60 strains belonging to 23 species. The optimization of the PMA concentration showed that 100 μM was considered optimal to effectively inhibit 106 CFU/mL dead cells, while only 103-104 CFU/mL dead cells could be inhibited in previous reports. This assay could detect viable Salmonella spp. at as low as 36 CFU/mL in pure culture and 100 CFU/g in raw shrimp. By comparing with PMA-qPCR, qPCR and plate counting for quantifying Salmonella in samples, this PMA-qPCR was obviously superior to qPCR and had good agreement with plate counting. In conclusion, this effective method can be used as an available tool to quantify viable Salmonella spp. in raw shrimp.
... The sterile solution obtained in this manner can be used for the treatment of fish and seafood without affecting taste and smell. In the study of Lin et al. (2014), shrimps were stored under acidic EW ice. From the observations, it appeared that the shrimps in EW ice maintained longer, compared to the sample under traditional ice, their initial characteristics. ...
Chapter
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Food safety is a priority for the food industry and to achieve this result a correct plant sanitation programme is of the utmost importance. Among various disinfection techniques, an emerging one is represented by the use of electrolysed water (EW) as the disinfecting agent. The use of EW is compliant with the desire to find alternatives to chlorination and heat treatments, representing a green cleaning alternative to toxic disinfectants. EW is an activated liquid, obtained by passing a diluted saline solution (NaCl, KCl or MgCl2) through an electrolytic cell, thus causing the production from the anode side of electrolysed oxidising water, containing high dissolved oxygen, free chlorine and characterised by a low pH (2.3–2.7) and a high oxidation–reduction potential (ORP>1,000 mV). At the same time from the cathode side electrolysed reduced water is produced, with high pH (10.0–11.5), high dissolved hydrogen and low ORP (�800 to �900 mV). Unlike other chemical disinfectants, EW is not harmful for skin and mucous membranes and is quite easy to handle. Furthermore, the use of EW is relatively inexpensive and, above all, is a sustainable technique. Currently used sanitisers (e.g. glutaraldehyde, formaldehyde, etc.) are effective, but their adverse effects on the environment are well known. Differently from these chemicals, the use of EW has a reduced impact on the environment and because of its properties, it may find several applications in the food industry. In this work, the characteristics and some EW applications as sustainable sanitation technique applied in the food industry are reported and discussed.
... In Korean fish markets, various types of seafood, including oysters, are sold from the same tanks containing seawater, which is a primary cause of cross-contamination (Jun et al., 2012). V. parahaemolyticus infections are more commonly reported in Asian countries than in European countries (Lin et al., 2013;Xu et al., 2013;Su and Liu, 2007). Among various types of seafood, raw fish and shellfish are the foremost sources of foodborne infections due to this organism (Sakazaki, 2002). ...
... The effect of EW in E. coli and Salmonella spp.present in freeze shrimp was studied, as well increasing quality (Loi-Braden et al., 2005). AEW in ice form was studied on shrimp quality preservation (Lin et al., 2013), in the dark conditions, where AEW ice is a good inhibitor of polyphenol oxidase enzyme, that cause melanosis and decrease in acceptability (Wang, Lin, Li et al., 2014). ...
Article
Full-text available
Electrolyzed water (EW) is a new technology that emerged in the last years with potential application in foods, mainly in microbiological aspects, with variation in application modes, dipping the food in solution, where variation of time can be changed and be apply in the form of spray. Because EW characteristics, its action in microorganisms are still been studied for mechanism elucidation and possible damages, as well its influence in the intrinsic characteristics of food, like color and oxidation. This unconventional or ‘green’ technology has the purpose to prove microbiological quality of food and decrease the use of natural resources like water with minimal generation of chemical/toxic residues. More studies are necessary in relation to this technology and its possible applications in food industry, as well characteristics and mechanisms.
... Shrimp is one of the most important fishery products in South and Southeastern parts of Asia, as well as an important economy characteristic in these areas (Lin et al., 2013;Xu et al., 2013). However, the contamination rate of V. parahaemolyticus has increased in shrimp culture environment year after year, and the natural germ-carry rate of shrimp could reach 90% in the warm seasons. ...
Article
The objective of this study was to investigate the fate of Vibrio parahaemolyticus on shrimp after acidic electrolyzed water (AEW) treatment during storage. Shrimp, inoculated with a cocktail of four strains of V. parahaemolyticus, were stored at different temperatures (4-30°C) after AEW treatment. Experimental data were fitted to modified Gompertz and Log-linear models. The fate of V. parahaemolyticus was determined based on the growth and survival kinetics parameters (lag time, λ; the maximum growth rate, μmax; the maximum growth concentration, D; the inactivation value, K) depending on the respective storage conditions. Moreover, real-time PCR was employed to study the population dynamics of this pathogen during the refrigeration temperature storage (10, 7, 4°C). The results showed that AEW treatment could markedly (p<0.05) decrease the growth rate (μmax) and extend the lag time (λ) during the post-treatment storage at 30, 25, 20 and 15°C, while it did not present a capability to lower the maximum growth concentration (D). AEW treatment increased the sensitivity of V. parahaemolyticus to refrigeration temperatures, indicated by a higher (p<0.05) inactivation value (K) of V. parahaemolyticus, especially for 10°C storage. The results also revealed that AEW treatment could completely suppress the proliferation of V. parahaemolyticus in combination with refrigeration temperature. Based on above analysis, the present study demonstrates the potential of AEW in growth inhibition or death acceleration of V. parahaemolyticus on seafood, hence to greatly reduce the risk of illness caused by this pathogen during post-treatment storage.
... Electrolyzed water (EW) is widely accepted as a practical disinfectant because it does not make use of hazardous chemical substances and processes [2]. Studies have shown that EW has gained immense popularity because of its ease of production and application; therefore, it has been extensively applied in food sanitization [1][2][3][4][5][6][7][8][9][10], environmental sanitization [11], livestock farming [12][13][14][15][16][17][18], and medical sterilization [19][20][21][22][23]. ...
Article
Currently, electrolyzed water, a sustainable and environmentally friendly disinfectant produced through electrolysis of an acid or salt, has become very popular because of its applications in various sectors such as health, agriculture, and food. Influencing factors are important for optimizing the electrolyzed water production process and maximizing application efficiency. Factors that influence the production and efficiency of electrolyzed water, including water and electrolyte properties, electrode material, current, storage, and application factors, were reviewed in this study. Moreover, some commercially available generator models, their specifications, and issues are discussed along with future recommendations. This work summarizes the available literature from January 2000 to December 2020, reporting studies that can assist in understanding various parameters affecting the production and stability of electrolyzed water. This can provide further insights and aid researchers in optimizing the process and address the issues faced by the existing systems by offering new perspectives in future studies.
... It is suggested that the AEW treatment on smoked-salmon did not alter texture, color and sensory perception of the food product [31]. Application of AEW ice on shrimp has demonstrated the potential ability in minimizing pH changes of shrimp flesh and significantly retarding the change of color, and it posed no adverse effect on the firmness of shrimp while had a capability to inhibit foodborne pathogen in shrimp [99]. However, there is insufficient studies investigate the effect of EW on seafood and fish quality hence more investigation should conducted. ...
Conference Paper
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Uncontrolled growth of microorganism in foodstuff pose a severe challenge to the food industry, as it could leads to food spoilage, or even foodborne disease if the microorganism is pathogenic. To deal with these threats, sanitizers has been widely applied widely by food industry. In the last two decades, electrolyzed water (EW) has been food to be a promising new sanitizer for food industry, as it is more environmentally friendly compared to conventional chlorine-based disinfectants. This paper reviews the recent progress on the application of EW as a food sanitizer. EW was produced by the electrolysis of diluted NaCl (or HCl) solution and could be classified into several subgroups (acid EW, slightly EW, neutral EW, alkaline EW, low concentration) based on their pH and available chlorine concentration. The efficacy of using EW to inhibit the growth of several most important microorganism of food safety concern were proven by numerous studies. Besides, the application of EW has been seldomly associated with detrimental effects on the nutritional and sensory proprieties of food. However, its antimicrobial potency was affected by factors such as pH, temperature, storage time, and organic matter.
... For the preservation of seafood, the AEW is normally frozen before use, and the term AEW ice is often used. AWE ice has been shown beneficial to improve the quality, shelf life, and food safety of several kinds of seafood, including shrimps (Lin et al., 2013;Wang et al., 2014;Zhang et al., 2015;Zhao et al., 2018) and squid (Xuan et al., 2017). Wang et al. (2014) suggested a primary mechanism improving the quality and safety of shrimps. ...
Article
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Recent years have shown a tremendous increase in consumer demands for healthy, natural, high-quality convenience foods, especially within the fish and seafood sector. Traditional processing technologies such as drying or extensive heating can cause deterioration of nutrients and sensory quality uncompilable with these demands. This has led to development of many novel processing technologies, which include several mild technologies. The present review highlights the potential of mild thermal, and nonthermal physical, and chemical technologies, either used alone or in combination, to obtain safe seafood products with good shelf life and preference among consumers. Moreover, applications and limitations are discussed to provide a clear view of the potential for future development and applications. Some of the reviewed technologies, or combinations thereof, have shown great potential for non-seafood products, yet data are missing for fish and seafood in general. The present paper visualizes these knowledge gaps and the potential for new technology developments in the seafood sector. Among identified gaps, the combination of mild heating (e.g., sous vide or microwave) with more novel technologies such as pulsed electric field, pulsed light, soluble gas stabilization, cold plasma, or Ohmic heat must be highlighted. However, before industrial applications are available, more research is needed.
... No negative effects were observed. [120] Farmed puffer fish (Takifugu obscurus) ...
Article
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Fish products are highly perishable, requiring proper processing to maintain their quality and safety during the entire storage. Different from traditional methods used to extend the shelf-life of these products (smoking, salting, marinating, icing, chilling, freezing, drying, boiling, steaming, etc.), in recent years, some alternative methods have been proposed as innovative processing technologies able to guarantee the extension of their shelf-life while minimally affecting their organoleptic properties. The present review aims to describe the primary mechanisms of some of these innovative methods applied to preserve quality and safety of fish products; namely, non-thermal atmospheric plasma (NTAP), pulsed electric fields (PEF), pulsed light (PL), ultrasounds (US) and electrolyzed water (EW) are analysed, focusing on the main results of the studies published over the last 10 years. The limits and the benefits of each method are addressed in order to provide a global overview about these promising emerging technologies and to facilitate their greater use at industrial level. In general, all the innovative methods analysed in this review have shown a good effectiveness to control microbial growth in fish products maintaining their organoleptic, nutritional and sensory characteristics. Most of the technologies have also shown the great advantage to have a lower energy consumption and shorter production times. In contrast, not all the methods are in the same development stage; thus, we suggest further investigations to develop one (or more) hurdle-like non-thermal method able to meet both food production requirements and the modern consumers’ demand.
... Meanwhile, SAEW-ice can extend the shelf life by 4-5 d compared with conventional ice water. AEW can inhibit the growth of bacteria in shrimp and significantly delay the color change and the increase of volatile basic nitrogen (p < 0.05) (Lin et al., 2013). This technology has broad-spectrum efficiency, safety, and environmental protection, the electrolyzed water generator structure is relatively simple, and the production cost is relatively low (Ma, et al., 2019). ...
Article
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This article reviews the research progress of non-thermal disinfection technologies in food and introduces the principles of non-thermal disinfection technologies such as ultra-high pressure, ozone, acid electrolyzed water, irradiation, magnetic sterilization, high-pressure carbon dioxide, and natural antibacterial. We discuss the characteristics and application progress of non-thermal disinfection technologies in food processing and analyze their development trend based on their application and promotion in food processing and storage.
... SAEW exhibits strong antimicrobial activity against many different kinds of microorganisms such as Escherichia coli [19], Staphylococcus aureus [19,20], Salmonella spp [21], Vibrio parahaemolyticus [22], and Bacillus cereus spores, etc. [23,24]. SAEW has been used to disinfect fresh fruits [25], vegetables [26,27], fish products [28,29], and meat products [30]. In addition, SAEW shows potential on controlling some phytopathogenic fungi. ...
Article
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Effects of ultrasound (US, 300, 400, and 500 W) and slightly acidic electrolyzed water (SAEW, 10, 30, and 50 mg/L) combination on inactivating Rhizopus stolonifer in sweet potato tuberous roots (TRs) were investigated. US at 300, 400, and 500 W simultaneous SAEW with available chlorine concentration of 50 mg/L at 40 and 55 °C for 10 min significantly inhibited colony diameters (from 90.00 to 6.00-71.62 mm) and spores germination (p < 0.05). US+SAEW treatment could destroy cell membrane integrity and lead to the leakage of nucleic acids and proteins (p < 0.05). Scanning and transmission electron microscopy results showed that US+SAEW treatment could damage ultrastructure of R. stolonifer, resulted in severe cell-wall pitting, completely disrupted into debris, apparent separation of plasma wall, massive vacuoles space, and indistinct intracellular organelles. US500+SAEW50 treatment at 40 and 55 °C increased cell membrane permeability, and decreased mitochondrial membrane potential of R. stolonifer. In addition, US500+SAEW50 at 40 °C and US300+SAEW50 at 55 °C controlled R. stolonifer growth in sweet potato TRs during 20 days of storage, suggesting effective inhibition on the infection of R. stolonifer. Therefore, US+SAEW treatment could be a new efficient alternative method for storing and preserving sweet potato TRs.
... EW ice is a novel concept developed recently to preserve the quality of aquatic products. Lin et al. (2013) demonstrated that AEW ice (pH = 2.46, ORP = 1124 mV, and ACC = 26 mg/L) inhibited the growth of aerobic bacteria on shrimp (Litopenaeus vannamei), and the maximum reductions of population achieved greater than 90% on day 6. Additionally, AEW ice significantly delayed the color change and the production of total volatile basic nitrogen (TVBN), as well as retaining the initial adherences between muscle fibers of shrimp. ...
Article
With the growing demand for safe and nutritious foods, some novel food nonthermal sterilization technologies were developed in recent years. Electrolyzed oxidizing water (EOW) has the characteristics of strong antimicrobial ability, wide sterilization range, and posing no threat to the humans and environment. Furthermore, EOW can be used as a green disinfectant to replace conventional production water used in the food industry since it can be converted to the ordinary water after sterilization. This review summarizes recent developments of the EOW technology in food industry. It also reviews the preparation principles, physical and chemical characteristics, antimicrobial mechanisms of EOW, and inactivation of toxins using EOW. In addition, this study highlights the applications of EOW in food preservation and safety control, as well as the future prospects of this novel technology. EOW is a promising nonthermal sterilization technology that has great potential for applications in the food industry.
... In addition, AEW served as a potential substance for decreasing the activity of cathepsin B and polyphenol oxidase. Lin et al. [10] also proved that AEW ice can mitigate changes in pH, color, and the formation of total volatile basic nitrogen of shrimp. Chung et al. [11] investigated how HClO and ClO 2 affect the disinfection of fresh vegetables and fruits, and the authors suggested that ClO 2 efficiently decreased the total bacterial counts, compared to the HClO treatment. ...
Article
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Mussel (Mytilus edulis) is an economic shellfish with a high nutritional value. Due to the high amount of protein and fat, fresh mussels are susceptible to spoilage during storage. In the present study, how a combination of pullulan, acidic electrolyzed water (AEW), and stable chlorine dioxide (ClO 2) ice-glazing treatments affect the quality of mussels was investigated during 90 days of frozen storage. The results indicate that the combined glazing treatment effectively maintained the mussel muscle quality during storage mainly due to its air barrier actions. Mussel samples coated with AEW and ClO 2 showed lower aerobic plate counts than other groups, resulting from the strong antibacterial action of AEW and ClO 2. After 90 days of frozen storage, the mussel glazed with a combination of AEW, ClO 2 , and pullulan solutions showed better texture properties, higher content of myofibrillar proteins, higher Ca 2+-ATPase activity, and more SH groups than the other glazing treatments. The water-holding capacity and SEM observations showed that the pullulan glazing efficiently inhibited the physical damage caused by the frozen and long-term storage, which mainly contributed to the high amount of hydrophilic hydroxyl groups in the muscle tissues. The present study supports the use of a combination of cryoprotectants for extending the shelf-life of frozen mussel products during long-term storage.
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Novel environment‐friendly heat‐storage materials with efficient cooling capacity are in high demand by the food, pharmaceutical, and related industries and supply chains. Better control and prevention of cross‐contamination caused by meltwater from traditional ice have become critical to ensure the safety and quality of food and other commodities. Here is reported a microbial‐resistant, reusable, and compostable novel stationary cooling medium, “Jelly Ice Cubes” (JICs), based on gelatin–menadione sodium bisulfite (MSB) hydrogels (Gel/MSB‐JICs) with cooling efficiency comparable with traditional ice. For the first time, the photo‐crosslinking reactions induced by MSB are proposed and validated theoretically and experimentally. Photo‐tuning is used collectively with rapid‐freeze‐slow‐thaw treatment to construct robust hydrogel frameworks against the functional and structural damages caused by the phase transition of water during repeated uses. Exceptionally stable cooling efficiency and robust mechanical strength are observed across ten application cycles, with stable antimicrobial functions against bacteria, fungi, and yeast. At the end of the lifecycle of JICs, they can be composted or used as a soil treatment to promote plant growth. The novel JICs are competent as promising, safer, and more eco‐friendly substitutes for traditional ice and ice packs.
Chapter
Food safety is a burning issue in the present world. Safe sanitizers are obligatory for maintaining quality of food and increasing the shelf life of fresh produce and other agricultural products. Food industries have been using electrolyzed water (EW) as a unique sanitizer for the past two decades which has excellent results to reduce the microbial count. Hurdle technology, e.g., combination of EW with ultrasonication, short-term heat treatment, organic acids, and salts, found to have more effective results in reducing microorganisms which overcame the little shortcomings with EW like corrosiveness and maintained organoleptic qualities. In this chapter, we are going to discuss the production of EW and its combination with ultrasonication, short-term heat treatment, organic acids, and salts to produce a novel sanitizer.
Article
A molecular predictive model of Vibrio parahaemolyticus on ready-to-eat shrimps was developed and four Vibrio parahaemolyticus strains in ready-to-eat shrimps at 4~30℃ were quantitated by Real-time PCR method. Gompertz model was selected as the primary model, which was fitted to achieve maximum growth rate (MGR) for Vibrio parahaemolyticus on ready-to-eat shrimps at 10~30℃. The MGR was then used to establish secondary molecular models as linear model, square root model and Ratkowsky model, and these models were validated subsequently. Weibull model, Log-linear model, and Logistic model were applied to predict inactive curves of V. parahaemolyticus at 4℃ and 7℃, respectively. Results showed that the V. parahaemolyticus growth data could be well fitted by Gompertz model (R2 > 0.96). The R2 values of linear model, square root model and Ratkowsky model were all above 0.94, and the Af and Bf values were within the acceptable limit, indicating that the relationship between the growth rates of V. parahaemolyticus and storage temperatures could be well described by the models, especially the Linear model. However, Real-time PCR method could not be used to develop the inactive model of V. parahaemolyticus at 4℃ and 7℃. Accuracy molecular predictive models developed by real-time PCR method can aid to establish models of certain pathogens more accurately in the presence of other bacteria.
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Electrolyzed water (EW) has gained immense popularity over the last few decades as a novel broad-spectrum sanitizer. EW can be produced using tap water with table salt as the singular chemical additive. The application of EW is a sustainable and green concept and has several advantages over traditional cleaning systems including cost effectiveness, ease of application, effective disinfection, on-the-spot production, and safety for human beings and the environment. These features make it an appropriate sanitizing and cleaning system for use in high-risk settings such as in hospitals and other healthcare facilities as well as in food processing environments. EW also has the potential for use in educational building, offices, and entertainment venues. However, there have been a number of issues related to the use of EW in various sectors including limited knowledge on the sanitizing mechanism. AEW, in particular, has shown limited efficacy on utensils, food products, and surfaces owing to various factors, the most important of which include the type of surface, presence of organic matter, and type of tape water used. The present review article highlights recent developments and offers new perspectives related to the use of EW in various areas, with particular focus on the food industry. From an industrial viewpoint, this publication can be used for the comparison and improvement of electrolyzed water (EW) generators. From a scientific standpoint, this publication can help in understanding the role of various parameters and can provide insight into EW producing systems and its applications for further research and development.
Article
The combined effect of slightly acidic electrolyzed water (SAEW) and ascorbic acid (AA) on the melanosis and quality of freshwater prawn (Macrobrachium rosenbergii) over a period of 6 days cold storage was investigated. AA solution (3 g/L) was used to immerse the prawn after prewashing with SAEW (pH 5.92; ORP, 810 mV; ACC, 20 mg/L). Prawn physicochemical (pH, texture and total volatile basic nitrogen), microbiological (total aerobic counts and psychrophilic bacterial counts) and sensory characteristics were all analyzed. SAEW + AA treatment could effectively retard melanosis, bacterial growth and protein degradation and maintain better texture and sensory characteristics compared with AA solution, AEW and SAEW treatment alone. The process efficiency of this combination was higher than that of individual treatment. SAEW + AA treatment prolonged the shelf life of freshwater prawn by 3 days during storage at 4 °C. The results indicate that immersion in AA combined with SAEW prewashing has potential as a promising method to maintain the quality and extend the shelf life of prawns during refrigerated storage.
Article
The objective of this study was to determine the efficacy of electrolyzed oxidizing (EO) water in reducing natural microbiota on radish seed and sprout during seed soaking and sprouting. EO water with different available chlorine concentrations (ACC, 15, 20, 28, 33 and 40 mg/L) and different pH (2.5, 3.5, 4.5, 5.5 and 6.5) were used to soak radish seeds for 12 h and the surviving population of total aerobic bacteria, yeast and mold, and germination rate were determined. On the other hand, EO water with ACC of 30 and 50 mg/L was applied to spray sprouts during seed sprouting and the antimicrobial efficacy of EO water, as well as length, gross weight and dry weight of sprout were evaluated. The results showed that the population of natural microbiota decreased with increasing ACC of EO water, while no significant difference was observed among EO waters with different pH levels that were applied while soaking the seeds. EO water with higher ACC and lower pH slightly reduced the germination percentage of radish seed during seed soaking. EO waters with ACC of 30 and 50 mg/L sprayed during seed sprouting resulted in 1.39 and 1.58 log reductions of total aerobic bacteria, yeast and mold, respectively, and improved the length, gross weight and dry weight of the sprouts. Therefore, EO water with low ACC and near neutral pH could be used to soak seeds and water sprouts throughout seed germination and sprouting to control the population of natural microbiota on seeds and sprouts.
Article
Microbial community plays a prominent role in food quality and safety, which was regarded as the major cause for food spoilage and foodborne disease. Pre-PCR propidium monoazide (PMA) treatment is an effective approach to exclude DNA amplification signal from dead cells, and application of this method in the analysis of bacterial community might help us better understand the diversity and distribution of viable bacteria in food. In this study, the effects of PMA treatment on bacterial community characteristics in shrimp were assessed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) fingerprinting technique. The results showed that the microbial diversity was dramatically influenced by PMA treatment. During storage at 4 °C, Shannon–Wiener index and PCoA analysis indicated there were significant differences between bacterial diversity in samples treated with and without PMA. At the level of species, compared with samples without PMA treatment, Vibrio cholera, Exiguobacterium acetylicum, Aeromonas enteropelogenes, Eubacterium multiforme, Vibrio mimicus in PMA-treated samples disappeared during storage. When samples stored at 25 °C, PMA treatment has little influence on banding patterns in DGGE profiles. In conclusion, this study provides an effective tool for precisely monitoring the diversity of viable bacteria in food samples, especially at low temperature.
Article
Ice refrigeration is one of the most widely used methods for food preservation with the use of a low temperature to delay the growth of any microbial contaminants. The production of safe edible ice with antimicrobial properties is of importance to food safety and human health, and has attracted increasing interest in recent years. This manuscript summarizes the advancements of the recent technologies to produce activated ice containing bactericidal agents, which can be potentially applied for the microbial decontamination and freshness retention of raw foods, such as fresh vegetables, seafood and fisheries. Cold atmospheric plasma and acidic electrolysis of water are two technologies that have been recently proposed for the treatment of water that is intended for the production of safe ice. Additionally, the application of ultraviolet light-emitting diode (UVC-LED) irradiation for the efficient disinfection of the edible ice is also discussed.
Article
The present work mainly investigated the effects of prepared chitosan‑sodium alginate-nisin (CS-SA-N) preservatives on the quality and bacterial phase of Penaeus vannamei shrimp during cold storage. Results showed that CS-SA-N preservatives treated samples had the lower pH, total volatile basic nitrogen (TVB-N), total viable count (TVC), and freeness (K) values than those of untreated ones during cold storage. The sensory evaluation results indicated that CS-SA-N preservatives treated shrimps had the higher comprehensive scores than those of untreated ones during whole storage. Microbial community of all samples was dominated by Proteobacteria. The initial predominant bacteria of fresh shrimps were Sphingomonas, Carnobacterium and Psychrobacter. Psychrobacter, Pseudomonas, and Shewanella, Acinetobacter and Vibrio were the predominant bacteria of untreated samples. CS-SA-N preservatives significantly decreased predominant microbial numbers by inhibiting the growth of Psychrobacter, Vibrio, Acinetobacter and Carnobacterium during cold storage. Therefore, the CS-SA-N preservatives could be used to prolong the shelf life of shrimp and guarantee its quality.
Chapter
Crustaceans are animals that do not have a vertebra and backbone and have a hard shell outside. The body of crustaceans is divided into three parts. These are head, thorax, and abdomen. Body consists of segments and jointed legs. Commercially used crustaceans can all be grouped together and called as decapods because they have 10 ft. The first leg pair is usually larger than the rest. These are called claws. Decapod crustaceans are distinguished from other crustaceans by having five pairs of pereiopods or ten walking legs. Shrimps, prawns, lobsters, and crabs are decapod crustaceans. Crustacean shellfish have economic importance and important places in trade of the world. These creatures are very sensitive to degradation and therefore care must be taken to maintain them immediately after catching or harvesting. Otherwise there may be significant quality and economic losses. For all these reasons, preservation and handling is an important issue for crustacean shellfish.
Article
Acidic electrolyzed water (AEW) ice is a novel technique for prolonging the shelf-life of foods, but there is limited knowledge of its preservation mechanism. A proteomics approach and 16S rRNA-based Illumina sequencing were employed to investigate the changes of key proteins and bacterial communities in shrimps stored in AEW ice and tap water ice (TW ice) for 7 days. Compared with TW ice, AEW ice markedly retards the degradation of myofibrillar proteins in shrimps, including myosin, actin and tropomyosin. Besides, sarcoplasmatic proteins which participate in carbohydrate catabolic process and amino acid metabolism were also influenced. Furthermore, the growth of spoilage bacteria which includes the genera Psychrobacter, Shewanella and Flavobacterium was significantly inhibited by AEW ice, and the inhibition rate at day 7 was 71.6%, 47.8% and 100% respectively (p<0.05). Further correlation analysis showed the links between spoilage bacteria and protein changes can be broken by AEW ice treatment. Collectively, our findings indicated AEW ice can improve the quality of shrimps via previously undescribed mechanisms, which retarded the degradation of myofibrillar proteins and inhibited the growth of spoilage bacteria.
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Electrolyzed oxidizing water (EOW) can be divided into acidic electrolyzed oxidizing water (AEOW) and slightly acidic electrolyzed water (SAEW). AEOW has the characteristics of low pH (pH < 2.7) and high oxidation-reduction potential (ORP > 1100 mV). SAEW is slightly acidic (pH = 5-6) and has an ORP of 700-900 mV. AEOW and SAEW both have a certain amount of active chlorine content (ACC), so they have the characteristics of broad spectrum, rapidity and high efficiency of sterilization. At present, there is little systematic research on AEOW and SAEW preparation. However, it is very important to study the preparation process, including electrode material and electrolytic process. First, the effects of Pt electrodes with different thermal decomposition temperatures on AEOW's pH, ORP and ACC values were investigated in detail. Next, for the SAEW preparation, the process is based on the preparation of AEOW by ion-exchange membrane electrolysis, reasonably mixing the electrolyzed cathode and anode solution. The effects of technological conditions such as electrolysis time, current density and electrolyte concentration have been systematically studied, and it is expected to get SAEW with a pH value slightly less than 7, a higher ORP value and a certain amount of ACC.
Chapter
The aquaculture industry has witnessed a continuous rapid growth over the last two decades from a combination of increased seafood consumption and production. These aquatic products filled a niche in the modern demand for alternate sources of protein. Electrolyzed water (EW), a novel non-thermal technique, is currently being used as an environmental-friendly sanitizer, and frozen electrolyzed water ice (EW ice) has emerged as an alternative method for improving the safety and quality of seafood. EW and EW ice whilst reducing microbial contamination also contribute to extending the shelf life of aquatic products compared to conventional sanitizers. This present chapter provides a comprehensive guide to the application of EW and EW ice on aquatic products and offers clear perspectives for a global adoption of EW in the seafood industry.
Chapter
Foods of animal origin, such as red meat and poultry products, are primary sources of superior protein for humans. With the production and consumption of these products increasing rapidly in recent decades, microbial safety and food quality are vital issues. Electrolyzed water (EW) as a sanitizer has awakened high interest in the food industry of many countries. The use of EW to decontaminate fresh red meat, ready-to-eat meat, poultry and shell eggs has been effective in reducing pathogenic microorganisms. Moreover, EW presents many advantages over traditional decontaminants; it provides effective antimicrobial activity and is environmentally friendly, simple to handle and relatively inexpensive. However, no complete elimination of pathogens on red meat and chicken meat was obtained after treatment of the meats with EW. This result probably occurs because organic matter and blood residue were present. This chapter provides a brief overview of how EW treatment affects foods of animal origin, especially the microbial safety and the physicochemical and sensory qualities of the food.
Chapter
The pathogenic microbial biofilm is gaining increasing concern in the food safety field. Biofilms may exist in food raw materials, food processing equipment as well as food products and packages during transportation and storage. Since the microbial biofilms have strong survivability in various pressure conditions (pH, temperature, ultraviolet, antibiotics, disinfectants, etc.) in food processing, they become a nonnegligible source of foodborne diseases, thus have potential threat to human health. Here, we focus on discussing the general phenomenon of food-associated pathogen biofilms, the survival mechanism of biofilms under various stimuli in food processing, commonly used detection methods, and the characteristic of virulence of biofilm.
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Mycotoxins widely contaminated the feed ingredients of shrimp, threatening the aquatic products, but their adverse effects on quality is less known. In this study, the adverse effects of T‐2 toxin (T‐2), aflatoxin B (AFB1), deoxynivalenol (DON), and ochratoxin (OTA) on the quality of Litopenaeus vannamei were investigated and compared. The results demonstrated that these four mycotoxins led the worse shrimp muscle color and tender texture, induced lipid peroxidation and pH change. Furthermore, four mycotoxins increased the K‐value and total volatile basic nitrogen (TVB‐N) to decrease the freshness. The median effective doses of T‐2, DON, AFB1, and OTA on TVB‐N of shrimp muscle were 4.86, 1.51, 0.26, and 0.20 mg/kg·bw, respectively. This study could provide useful information about the impacts and limited exposure dose of mycotoxins for quality preservation of shrimp. Practical applications The shrimp quality is easy to deteriorate as it is most likely to be exposed to mycotoxins because of intensive farming practices using grain‐based feeds, which were widely contaminated by mycotoxins. This study may provide a limited exposure dose of four prevailing mycotoxins aflatoxin B, deoxynivalenol, ochratoxin, and T‐2 for preserving the minimal quality of shrimp, and also provide useful information for predicting the quality of shrimp from those highly mycotoxins‐contaminated areas.
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The obscure puffer fish (Takifugu obscurus) is underutilized as a food fish. To improve the quality of puffer fish flesh, the fish samples were preserved after treating them with electrolysed water (EW), a combination of EW and chitosan (EW/chitosan), or a combination of EW and carboxymethyl chitosan (EW/CMC). The effects of these treatments were compared by analysing changes in the total viable count of aerobic bacteria, firmness, total volatile basic nitrogen, trimethylamine, pH, the thiobarbituric acid and sensory attributes of the refrigerated puffer fish. Changes in the myofibril length of puffer fish flesh was also studied, which is related to flesh softening. The findings suggest that during storage, EW/chitosan treatment is more effective than both EW and EW/CMC treatments in inhibiting microbial growth and myofibril degradation, and in maintaining the quality of obscure puffer fish flesh. This could extend the shelf life by 50% of the original shelf-life of about 4 days of the fish samples.Highlights► We use three different treatments to preserve obscure puffer fish flesh. ► We study changes in the myofibril length of puffer fish flesh during storage. ► EW/chitosan treatment extends the shelf life by 50% of the original shelf-life. ► The decrease in myofibril length is related to the firmness changes of fish flesh.
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The sensory, microbiological and biochemical changes were determined in shrimp (Penaeus merguiensis) stored at 0° to 35°C. Mean aerobic plate count of fresh shrimp, initially 5.0 × 105 CFU/g, increased with time and temperature to 6.4 × 109 CFU/g at 35°C after 24 hr. A total of 560 different bacteria were isolated and identified. In addition, the dominant organisms were tested for ability to reduce TMAO, produce indole and hydrolyze protein. The initial bacteria were 30% Gram + organisms but changed to predominantly Grampsychrotrophs at lower temperatures and to mesophiles at higher temperatures. Odor, texture and color qualities decreased; TMA, TVB, pH and Indole increased with time and temperature. Shelf life of shrimp ranged from 7 hr at 35°C to 13 days at 0°C.
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The objective of this study was to determine the changes in the quality of coated trout fillets after coating with edible materials. Fillets were coated and stored at −18 °C for a period lasting up to 7 months. Coating materials were applied in three different stages (first, second, and last coatings). The coated fillets were fried and analyzed for oil absorption and moisture content throughout the storage period. Sensorial attributes and the physical–biochemical changes were also measured before the frying process in each month. It was observed that it is more advantageous to use gluten as the first coating, xanthan gum as the second coating, and wheat (W) and corn (C) flours in the ratio of 1:1 or 2:1 as the last coating. In terms of the fillet quality, the following results were obtained in the analyses conducted before frying. The lowest pH found was 6.25 in zein-containing samples and 6.30 in guar-containing samples. The effects of the last coatings on pH were unimportant (P > 0.05). The lowest thiobarbituric acid levels found were 2.07 mg kg in the fillets coated with casein mixture, 2.44 mg kg in the fillets coated with xanthan gum, and 2.25 mg kg in the fillets coated with W:C flour mixture in the ratio of 2:1. The lowest total volatile basic nitrogen levels found were18.06 mg 100 g in the fillets coated with casein mixture, 18.62 mg 100 g in the fillets coated with xanthan gum, and 18.47 mg 100 g in the fillets coated with W:C flour mixture at 1:1 ratio. In the sensorial analysis, the coated samples were much more preferred than those not coated. As a result of the effects of all the materials, the coating layers on the meat surface provided more resistance against mass transfer during storage.
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This report investigated the melanosis-inhibiting properties of crude water soluble extract from the base and fruiting body waste of an edible mushroom (Flammulina velutipes) containing 9.13±2.03mg/mL 2-thiol-l-histidine-betaine (ergothioneine, ESH). Immersion of live full-grown black tiger shrimp (Penaeus monodon) and Pacific white shrimp (Litopenaeus vannamei) in a 0.5% w/v solution of mushroom extract for 1h significantly decreased polyphenoloxidase (PPO) activity in shrimp hemolymph and expression of the prophenoloxidase (proPO) gene in hemocytes. Consequently, the development of melanosis in the treated shrimp during ice storage was prevented. Treatment with a 0.05% w/v solution of sodium sulfite and 4-hexyl-1,3-benzenediol had a similar effect. Enzyme assays showed that ESH is a non-competitive inhibitor. It is proposed that ESH possibly interacts directly with Cu2+ at the putative binding sites of PPO and proPO, based on copper-chelating activity analyses, thus preventing melanosis in the shrimp. This study indicated that application of ESH-rich F. velutipes mushroom extract from trimming waste is an effective natural alternative to synthetic melanosis-inhibiting agents to prevent postmortem melanosis in shrimp.
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The use of ozonised slurry ice was investigated as a new refrigeration system for the storage of farmed turbot (Psetta maxima). With this purpose in mind, an ozone generator device was coupled to a slurry ice system working subzero at −1.5 °C. The ozone concentration was adjusted to a redox potential of 700 mV, and the slurry ice biphasic mixture was prepared at a 40% ice/60% water ratio and 3.3% salinity. Certain biochemical parameters indicative of fish freshness, such as the rate of nucleotide degradation or TMA-N formation, were not significantly affected by the presence of ozone in the slurry ice mixture. However, storage in ozonised slurry ice significantly slowed down the mechanisms responsible for lipid hydrolysis and lipid oxidation in farmed turbot. Storage in ozonised slurry ice also led to significantly (p
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Slurry ice, a biphasic system consisting of small spherical ice crystals surrounded by seawater at subzero temperature, was evaluated as a new chilled storage method for whole European hake (Merluccius merluccius), a gadoid fish species of remarkable commercial interest, and this method was compared with a control batch stored for 19 days in traditional flake ice. The results obtained in the sensory analysis indicated a significant extension of shelf-life – from 5 days (flake ice batch) to 12 days (slurry ice batch) – in the latter batch, mainly deriving from a better maintenance of both external and fresh odour, the appearance of the gills and consistency. The slurry ice batch exhibited a significantly lower increase in pH as compared to the flake ice batch, this indicating a better control of the former over alkalinising microflora. Thus, significantly lower counts of total aerobes and proteolytic bacteria were also attained in hake muscle stored in slurry ice, microbial numbers reaching average differences of ≈1 log unit before 12 days of storage and above 2 or 3 log units, respectively, when this period was extended up to 19 days. The formation of total volatile base-nitrogen and trimethylamine were also significantly lower in the slurry ice batch after 12 days of storage. According to the parameters assessed, storage of European hake in slurry ice extends the shelf-life of this species and allows a better maintenance of sensory and microbiological quality.
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Atlantic salmon (Salmo salar) fillets were stored on ice for a maximum of 14 d to determine which muscle structures are associated with changes in texture and rigor. Texture was measured as shear force and the changes correlated with structural alterations. Texture decreased significantly within 24 h in parallel with loss of attachment of muscle fibers. Loss of rigor stiffness by 5 d was associated with myofiber detachment from the myocommata. These results show that fillet texture depends on several distinct structures and events, initially including breaks in the cell cytoskeleton and loss of fiber-fiber attachment and later breaks in the connective tissue and fiber detachment from the myocommata.
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The storage of deepwater pink shrimp (Parapenaeus longirostris) in modified atmosphere was studied. Two gas mixtures were tested (40% CO2/30% O2/30% N2 and 45% CO2/5% O2/50% N2), combined with sulfites-based pretreatment, in comparison with air storage. The quality of shrimp was evaluated by sensory (black spot presence) and chemical analyses (pH value and nucleotides breakdown products). Generally, both atmospheres preserved the shrimp quality up to 9 d compared with 4 to 7 d of ice storage (only with pretreatment), although it seems that atmosphere containing 45% CO2/5% O2/50% N2 was the most effective.
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Denaturing gradient gel electrophoresis (DGGE) profiles of PCR amplified V3 regions of 16S rRNA genes were used to assess the diversity in enrichment cultures with methane as the only carbon and energy source. The enrichments originated from two agricultural soils. One was a sandy soil with low (10%) organic content, the other an organic soil with approximately 50% organic content. DGGE provided a fast evaluation of the distribution of amplifiable sequence types indicating that specific bacterial populations had been enriched from each soil. The DGGE profiles revealed a broader range of amplified V3 fragments in the community derived from organic soil than from sandy soil. Fragments from 19 individual DGGE bands were sequenced and compared with 27 previously published 16S rRNA gene sequences. The sequences confirmed the high diversity with the presence of different methylotrophic populations in each enrichment. No affiliation was found with type I methanotrophs, instead type II methanotroph sequences were found in the enrichments from both soil types. Some of the fragments from the organic soil enrichment were not affiliated with methylotrophs. Most of the sequences clustered distantly on a branch within the α-Proteobacteria. These facts suggested that previously undescribed methylotrophs are abundant in methane enrichments from agricultural soil.
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Among different fish slices used for sashimi preparation, tuna is the most popular and preferable fish type for Taiwanese people. To improve the hygienic quality of fish slices, electrolyzed (EO) water containing 10, 50, and 100 mg/L chlorine, was used in combination with CO gas treatment. Effect of different treatment on aerobic plate count (APC), volatile basic nitrogen (VBN), K value, and Hunter L*, a*, b* values of yellow-fin tuna steak during storage (4 °C and −20 °C) were evaluated. It was found that APC, VBN, and K values increased with storage time for all treatment. Except for K value, APC and VBN of tuna steak treated with the combination of more than 50 mg/L chlorine EO water and CO gas had the lowest value after 8 d of refrigerated storage. Hunter a* value of tuna steak treated with only CO gas was the highest, followed by those treated with EO water and CO gas. These results demonstrated that EO water containing 50 mg/L chlorine combined with CO gas treatment in tuna fish steak would be an effective method for enhancing the hygienic quality and freshness for tuna meat and extending refrigerated storage time. Tuna treated with EO water containing 100 mg/L chlorine and CO gas combination had the lowest APC immediately after treatment and reduced further to below detection limit after 1 mo frozen storage at −20 °C.
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European sea bass (Dicentrarchus labrax) is one of the finfish species preferred by the consumer, who requires fish freshness to be maintained during distribution and retail. For this reason, the purposes of this study were to define: the shelf life at three storage temperatures (−0.5, 4.8 and 16.5 °C) by applying both chemical (TVB and TBA assays) and olfactometric (e-nose) method; the actual time–temperature exposure conditions during marketing; the prediction of remaining shelf life in the commercial chain, on the basis of time–temperature history data and on appropriate integration routine. Shelf life study revealed the efficacy of chemical markers and electronic nose in describing the freshness decay and in defining a freshness threshold. Freshness of sea bass was kept for about 8 days for fish preserved in melting ice (−0.5 °C), 4 days at 4.8 °C and about 1 day at 16.5 °C. When fresh European sea bass was purchased, 9 out of 10 times the remaining shelf life was more than 55% at an average temperature of 1.19 °C. Therefore, the freshness of fish can be assured for 3–4 days in commercialization. A joint effort (sales point management and consumer advertising) could reduce the exposure temperature by 1–2 °C and justify an extension of the shelf life to 2–3 days after purchase.
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This study investigated efficacy of electrolyzed oxidizing water (EO water) and ice (EO ice) treatments in reducing histamine-producing bacteria (Enterobacter aerogenes, Enterobacter cloacae, Klebsiella pneumoniae, Morganella morganii and Proteus hauseri) on food contact surfaces (ceramic tile and stainless steel) and fish skin (Atlantic salmon and yellowfin tuna). Soaking ceramic tile and stainless steel in EO water (50 ppm chlorine) for 5 min inactivated inoculated bacteria on the surface (>0.92 to >5.4 log CFU/cm2 reductions). E. cloacae, K. pneumoniae and P. hauseri did not survive well on fish skin. Soaking salmon skin in EO water (100 ppm chlorine) for 120 min resulted in 1.3 and 2.2 log CFU/cm2 reductions of E. aerogenes and M. morganii, respectively. A treatment of EO ice (100 ppm chlorine) for 24 h was capable of reducing E. aerogenes and M. morganii on tuna skin by 2.4 and 3.5 log CFU/cm2, respectively. EO water and EO ice can be used as post-harvest treatments for reducing histamine-producing bacteria on food contact surfaces and fish skin.
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Freshness assessment of European eel (Anguilla anguilla) stored in ice and in boxes without ice at 3 ± 1 °C was assessed by sensory, chemical (total volatile basic nitrogen (TVB-N), thiobarbituric values (TBA), peroxide value (PV), free fatty acid (FFA), and pH) and microbiological (total viable counts, TVC) methods. The limit for sensory acceptability of eel stored in ice was ∼12–14 days, and ∼5–7 days at 3 ± 1 °C. TVB-N level of about ≥10 mg TVB-N 100 g−1 flesh could be regarded as the limit of acceptability. PV values and the release of FFA increased during storage in ice and at 3 ± 1 °C but the increases were greater at 3 ± 1 °C. Values of pH showed no statistically significant (P > 0.05) changes for eel stored in ice and at 3 ± 1 °C. Water losses of fillets stored at at 3 ± 1 °C were higher (P < 0.05) than those stored in ice. TBA values were found to fluctuate under both storage conditions. This study shows that sensory analysis of eel correlated well with microbiological analysis. The acceptability of eel decreased as TVB-N, FFA, PV and TVC values increased.
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Chemical, microbiological and sensorial changes of striped catfish (Pangasius hypophthalmus) slices treated without and with tannic acid (100 and 200 mg/kg) were determined during 15 days of storage at 4 °C in air and under modified atmospheric packaging (MAP, 60% N2/35% CO2/5% O2). The slices consisted of 9.2 g lipid/100 g and the lipid contained 64.55% unsaturated fatty acids and 33.87% saturated fatty acids. During the storage, the sample treated with 200 mg/kg tannic acid and stored under MAP (M2) had the lowest peroxide value (PV) and thiobarbituric acid-reactive substances (TBARS) with the coincidental lowest non-haem iron content, indicating the retarded lipid oxidation. Fourier transform infrared (FTIR) spectra indicated the formation of primary oxidation products and free fatty acids in M2 sample after 15 days. Conversely, these compounds were found at lower contents in the control samples kept in air without tannic acid treatment (A0), suggesting that the deterioration was more advanced. Myosin heavy chain of A0 was degraded by 17.85% after 15 days of storage, whereas no change was noticeable in M2, compared with the fresh sample (F). Based on microbiological acceptability limit (107 cfu/g), the shelf-life of A0 and M2 was estimated to be 3 and 15 days, respectively. M2 had the acceptable scores for all sensory attributes up to 15 days, while A0 was acceptable when stored for 9 days. Therefore, tannic acid exhibited a synergistic effect with MAP on retarding lipid oxidation and microbial growth, thereby increasing the shelf-life of striped catfish slices during refrigerated storage.
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Electrolyzed oxidizing (EO) water has been regarded as a new sanitizer in recent years. Production of EO water needs only water and salt (sodium chloride). EO water have the following advantages over other traditional cleaning agents: effective disinfection, easy operation, relatively inexpensive, and environmentally friendly. The main advantage of EO water is its safety. EO water which is also a strong acid, is different to hydrochloric acid or sulfuric acid in that it is not corrosive to skin, mucous membrane, or organic material. Electrolyzed water has been tested and used as a disinfectant in the food industry and other applications. Combination of EO water and other measures are also possible. This review includes a brief overview of issues related to the electrolyzed water and its effective cleaning of food surfaces in food processing plants and the cleaning of animal products and fresh produce.
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The safety of electrolyzed seawater was evaluated by measuring the production rate of organic halogen compounds and the occurrence of reverse mutations. Aquaculture feedwater and wastewater were collected from a fish-culturing facility, and available chlorine of approximately 1.0 mg/L was generated to ensure a disinfectant effect. More than 90% of the generated organic halogen compounds were bromoform. The amount of bromoform was far less than the reference values for drinking water standards in Japan and the U.S., provided that the electrolyzation was performed within the range of normal use. The reverse mutation assay of electrolyzed seawater showed no mutagenicity. Electrolyzed seawater with available chlorine at an adequate level for disinfection can be used safely and effectively in various aspects of aquaculture.
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