Article

Shelf-life of pacific white shrimp (Litopenaeus vannamei) as affected by weakly acidic electrolyzed water ice-glazing and modified atmosphere packaging

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Abstract

The combined effect of weakly acidic electrolyzed water (WAEW) ice-glazing and modified atmosphere packaging (MAP) treatment on the quality of pacific white shrimp (Litopenaeus vannamei) during frozen storage was investigated in terms of microbiological activity, TVBN, TMA and TBARS content, texture, color and volatile flavor analysis. As a result, significantly (p < 0.05) higher inhibitor effects on total aerobes and Staphylococcus aureus were observed in WAEW ice-glazed shrimp packaged in 40% CO2 + 10% O2 + 50% N2 or in 30% CO2 + 20% O2 + 50% N2 than the water- and WAEW ice-glazed batches. Additionally, chemical analysis results showed that WAEW ice-glazing combined with MAP was highly effective in maintaining lower TVBN, TMA and TBARS values in frozen shrimp, perhaps due to the synergistic effect of antibacterial and antioxidant abilities. On the other hand, the texture, L*, and a* results also confirmed that this combined treatment effectively retarded the degradation of the physical structure of shrimp muscle and showed a positive effect on the stability of color during frozen storage. However, the presence of WAEW ice-glaze showed a negative effect on the volatile flavor of thawed shrimp due to the volatile chlorine and chlorine dioxide, but no significant effect in the cooked samples. Overall, the application of WAEW ice-glazing combined with MAP on peeled frozen shrimp is advisable to achieve better quality maintenance and extend the shelf-life of refrigerated products.

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... HPCD at 310 bar (31 MPa), 1875 L of CO 2 , and 37°C was to produce low-cholesterol shrimps [5], and that at 20 MPa was for the prevention of shrimp melanosis [6]. HPCD in the range of 20-25 MPa and 37°C was performed for kinetic inactivation of PPO [7], while extraction of shrimp-waste astaxanthin was performed at 200 MPa for 5 min with the use of ethanol cosolvent [8]. ...
... Ash content of the shrimps treated at 1100 psi significantly increased (p ≤ 0.05) compared with the other samples. A decrease in moisture content can cause a relative increase in protein, fat, and ash [7]. Table 3 displays the reduction number of aerobic bacteria in treated shrimp with HPCD. ...
... e initial TVB-N value of untreated and treated shrimps was 9.33 and 9.95 mg/100g, respectively. e TVB-N scales of acceptability for raw shrimps are <12 mg N/100 g for fresh, 12-20 for edible but slightly decomposed, 20-25 for borderline, and >25 mg N/100 g for inedible and decomposed [7]. All shrimps showed an increase of TVB-N during 10 days of storage. ...
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... And commonly caught or farmed as an important food source. It is rich in protein, cellulose, mineral elements, vitamins, and a variety of amino acids that are beneficial to the human body (Zhang, Ma, Deng, Xie, and Qiu, 2015). Over the past 20 years, continuous advancement of shrimp farming technology in China and the widespread production of new aquaculture breeds have become more apparent. ...
... The TPA was performed under the following conditions: constant test speed, 1.0 mm/s; sample deformation, 50%; hold time between cycles, 3 s; and trigger force, 0.05 N. The TPA parameters were calculated from the forcetime curves generated from each sample using the FTC-PRO software. Each test was repeated eight times (Zhang et al., 2015). ...
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Pacific White Shrimps (Litopenaeus vannamei) are an aquaculture species with global importance. For the purpose of this paper, the quality shelling process of Pacific White Shrimps, freshly harvested from farms and stored in a mixture ice water up to 24 hr, was investigated. Both the differences and correlations between the indexes such as peeling time, shrimp yield, chromatic aberration, texture, K value, TBA value, and microstructure were compared and analyzed. The optimal shell peeling time of Pacific White Shrimps was determined by ice water treatment for 8 hr. The shell peeling time was 1.77 min, the elasticity of the shrimp was 0.51 mm, the hardness was 2,124.58 g, K value was 1.33%, and TBA value was 0.004 mg/100 g. Both the smell and color of the shelled shrimp were normal. This study aims to endorse the mechanical shelling of Pacific White Shrimps. For the purpose of this paper, the quality shelling process of Pacific White Shrimps, freshly harvested from farms and stored in an ice water mixture for up to 24 hr, was investigated. Both the differences and correlations between the indexes such as peeling time, shrimp yield, chromatic aberration, texture, K value, TBA value, and microstructure were compared and analyzed. This study aims to endorse the mechanical shelling of Pacific White Shrimps.
... The evaluation of the posttreatment effect of EW treatment often demonstrated the dynamics of food microbiota associated with a decrease in the organoleptic characteristic of fresh produce during storage (Botta et al. 2018). To avoid posttreatment microbial survival, the combination of EW treatment with modified atmosphere packaging technology has been applied to limit the complex dynamics of spoilage and pathogenic bacteria and the associated decrease in quality of meat, shrimp muscle, and sweet cherries (Eda and Seckin 2015;Posada-Izquierdo et al. 2014;Zhang et al. 2015). Modified atmosphere packaging containing a concentration of 40-80% CO 2 is effective in the preservation of fresh produce safety and quality, primarily due to CO 2 retardation of growth by extension of the survival lag phase of microorganisms during storage in MAP containing high CO 2 levels (Qian et al. 2013;Zhang et al. 2015). ...
... To avoid posttreatment microbial survival, the combination of EW treatment with modified atmosphere packaging technology has been applied to limit the complex dynamics of spoilage and pathogenic bacteria and the associated decrease in quality of meat, shrimp muscle, and sweet cherries (Eda and Seckin 2015;Posada-Izquierdo et al. 2014;Zhang et al. 2015). Modified atmosphere packaging containing a concentration of 40-80% CO 2 is effective in the preservation of fresh produce safety and quality, primarily due to CO 2 retardation of growth by extension of the survival lag phase of microorganisms during storage in MAP containing high CO 2 levels (Qian et al. 2013;Zhang et al. 2015). The CO 2 concentration inside food packages plays a particularly important role in decreasing the respiration rate, reducing the production of ethylene, and retarding senescence (Eda and Seckin 2015;Izumi and Inoue 2018). ...
... A negative effect on the quality of products at the end of the freezing storage of shrimp has also been observed (Gonçalves and Junior 2009;Soares et al. 2013). Zhang et al. (2015) studied the potential of weakly acidic electrolyzed water (WAEW) ice-glazing (pH 6.4-6.6 and an ACC of 6.4-6.5 mg/L) combined with MAP on the quality of peeled shrimp during frozen storage. The chemical analysis results demonstrated that combining WAEW ice-glazing and MAP generated a great synergistic effect of antibacterial and antioxidant properties capable of maintaining lower TMA, TBARS, and TVBN values in frozen samples. ...
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Improving the quality and safety aspects of fresh produce is one of the key issues in the food industry. EW is one of the most widely used sanitizers and is considered as an alternative technology to sodium chlorite treatment in the fresh produce industry. EW is well known to have a potential of microbial reduction of approximately 2 log CFU. The potential of this enhancement requires the application of combinations of EW with appropriate technologies susceptible to promoting standards in both microbial quality and safety and the sensory properties of fresh produce. In recent years, an increasing number of publications have shown that EW hurdle technology is considered as a potential food decontamination process, which can improve the microbial quality and safety and extend the shelf life of fresh produce. This chapter presents a complete picture of recent developments in EW hurdle technology applied to fresh produce, with a particular emphasis on microbial quality and safety. Several studies have been conducted to develop effective combined treatments of EW and thermal, chemical (especially organic), physical nonthermal, and various biological technologies. More specifically, the common use of chemical and biological treatments in simultaneous combination and the use of physical treatments in subsequent combination with different types of EW, including alkaline, acidic, and slightly acidic, are highlighted. The principles, mechanism of microbial and enzymatic inactivation, and microbial decontamination issues that can be overcome using a combination of EW with other treatments are also discussed. There are indications that the hurdle technology of EW can be used in the fresh produce industry; however, a better understanding of practical knowledge and the optimization of parameters of different treatments associated with EW would also contribute to reinforcing the future application of EW hurdle technologies in the fresh produce industry.
... As a substitute for tap water ice, electrolyzed water ice has also been used to ensure the freshness of the aquatic products. Zhang et al. [19] combined the ice-glazing with weakly acidic electrolyzed water (WAEW) and modified atmosphere packaging (MAP) in the preservation of frozen shrimp, which was shown to be highly effective in maintaining its physicochemical properties. The quality of the aquatic product can be significantly improved when it is placed on or in ice, which was also confirmed by Xuan et al. [20] However, as far as we know, there are relatively few studies on the combined effect of SAEW and SAEW-ice on the preservation of pomfrets. ...
... As expected, the pomfrets in the TW group had the highest TVC value, followed by the SAEW, TW-ice, SAEW-ice, and SAEW+SAEW-ice groups during the storage period. To a certain extent, our results indicated that SAEW, TW-ice, and SAEW-ice induced an effective delay in bacterial growth, as demonstrated by Zhang et al. [19] and Xuan et al. [20] . Moreover, the combination of SAEW and SAEW-ice allowed for good retention of the fish quality, which is inferred from the lowest TVC value of the combination treatment among the five groups. ...
... Noticeably, the similar primary texture within 1 d between the SAEW and the TW-ice groups might indicate that SAEW pretreatment could replace TW-ice for a short time without ice. The changes mentioned in hardness, gumminess, and chewiness could be attributed to changes in the proteins and lipids of the fish muscle tissue caused by enzyme reactions and bacterial reproduction [19] . Based on the maintenance of texture by the combined treatment (SAEW+SAEW-ice), it is likely to deduce that the combination of SAEW and SAEW-ice could inhibit the changes in the protein, lipid, and microbial population, which corresponded with the results of the TVBN, TBA and TVC values. ...
... Figure 2 reports the TBARs values found in the S. mantis flesh during the frozen storage, which varied from 1.4 to 2.4 mg MDA/kg for all the considered period, without significant variations in all storage conditions. Despite the secondary lipid oxidation initially induced by the mechanical separation process, TBARs did not show a steady increase during storage as expected, being thus in disagreement with data reported by various authors for oxidative stability of crustacean flesh and minced fish during frozen storage [3,[27][28][29][30]. Sundararajan et al. [18] found a value of 0.47 mg MDA/kg in shrimp that increased progressively during frozen storage up to 2.96 after 180 days. ...
... reports the TBARs values found in the S. mantis flesh during the frozen storage, which varied from 1.4 to 2.4 mg MDA/kg for all the considered period, without significant variations in all storage conditions. Despite the secondary lipid oxidation initially induced by the mechanical separation process, TBARs did not show a steady increase during storage as expected, being thus in disagreement with data reported by various authors for oxidative stability of crustacean flesh and minced fish during frozen storage[3,[27][28][29][30]. Sundararajan et al.[18] found a value of 0.47 mg MDA/kg in shrimp that increased progressively during frozen storage up to 2.96 after 180 days. ...
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Despite their high nutritional value, high quantities of fish caught in the Adriatic Sea are underused or discarded for their insignificant economic value. Mechanical separation of flesh represents an opportunity for developing innovative semi-finished products, even if it can promote an increased quality degradation rate. The aim of this study was to evaluate physico-chemical modifications of mechanically separated mantis shrimp flesh during deep-freezing storage. Flesh samples obtained using a belt-drum separator, frozen and vacuum-packed, were stored at 3 temperatures (industrial: −26 • C; domestic: −18 • C and abuse: −10 • C) for 12 months. During storage, qualitative (color, water content, pH, fatty acids (FA) and lipid oxidation) were evaluated. Fish freshness parameters (e.g., trimethylamine (TMA), dimethylamine (DMA) and amino acids) were assessed using nuclear magnetic resonance (1 H-NMR). The mechanical separation process accelerated the initial oxidation phenomena, promoting color alterations, compared to manual separation. The main degradation phenomena during storage were significantly affected by temperature and were related to changes in luminosity, oxidation of n-3 polyunsaturated fatty acids (PUFA), increased lipolysis with release of free FA, production of TMA and DMA by residual enzymatic activity, and changes in amino acids due to proteolysis. The inter-disciplinary approach permitted important findings to be made, in terms of the extent of different degradative phenomena, bound to processing and storage conditions of mechanically separated mantis flesh.
... • lightness L*, that represents the brightness on a scale from 0 (dark) to 100 (white); • red/green chromaticity a*, a scale ranging from negative values for green to positive values for red; • yellow/blue chromaticity b* that scale ranges from negative values for blue to positive values for yellow (Zhang et al., 2015). ...
... In the present study, it was observed that açaí supplementation influenced the color pattern of fresh and cooked shrimp ( Fig. 1 and Fig. 2). Numerous studies suggest that the decrease in a* values could be mainly attributed to the degradation of astaxanthin and lipid oxidation (Bernal Rodríguez et al., 2017;Wade et al., 2015;Zhang et al., 2015). In contrast, our results showed an increase in the a* parameter (redness) both in the surface of the cephalothorax and abdominal region of cooked shrimp exposed to T, A, and T þ A. A previous study by Silva et al. (2020) also reported a reddish color in L. vannamei shrimp fed with 10.0% açaí, given support to the idea of bioactive molecules (as astaxanthin) transference from açaí pulp to the shrimp. ...
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The chemoprotection of “buriti” Mauritia flexuosa (inclusion in diet: 0-control group; 1.25; 2.50; 5.00; and 10.00% W/W) to Litopenaeus vannamei postlarvae (PL) exposed to ammonia or nitrite was investigated. Analyzed variables include antioxidant (ACAP) and oxidative damage (TBARS) responses and levels of total carotenoids. The results indicated that there was no significant difference (p >0.05) in zootechnical variables between diets. The PL carotenoid content (R2 = 0.86), ACAP (R2 = 0.78), and TBARS (R2 = 0.91) showed a dose-dependent relationship with the inclusion levels of “buriti” (p <0.05). After 43 days, juvenile shrimps were exposed for 96 h to ammonia (0.48 mg NH3-N L-1) or nitrite (40 mg NO3 L-1). Higher scavenging activity against peroxyl radicals was observed in PL fed with 2.50 and 5.00% of “buriti” (ammonia exposure), or 5.00 and 10.00% (nitrite exposure) of “buriti” inclusion. Content of reduced glutathione was higher in shrimps exposed to ammonia and fed with 10.00% of “buriti”. Lipid peroxidation levels were lower in shrimps exposed to ammonia or nitrite and previously fed with inclusion higher than 2.50% of “buriti”. The increased scavenging activity and lower lipid peroxidation in ammonia or nitrite-exposed organisms and previously supplemented with “buriti” point to a hormetic response that increases the resilience of L. vannamei to cope with nitrogenous compounds, pointing to the use of this fruit as a chemoprotectant agent.
... • lightness L*, that represents the brightness on a scale from 0 (dark) to 100 (white); • red/green chromaticity a*, a scale ranging from negative values for green to positive values for red; • yellow/blue chromaticity b* that scale ranges from negative values for blue to positive values for yellow (Zhang et al., 2015). ...
... In the present study, it was observed that açaí supplementation influenced the color pattern of fresh and cooked shrimp ( Fig. 1 and Fig. 2). Numerous studies suggest that the decrease in a* values could be mainly attributed to the degradation of astaxanthin and lipid oxidation (Bernal Rodríguez et al., 2017;Wade et al., 2015;Zhang et al., 2015). In contrast, our results showed an increase in the a* parameter (redness) both in the surface of the cephalothorax and abdominal region of cooked shrimp exposed to T, A, and T þ A. A previous study by Silva et al. (2020) also reported a reddish color in L. vannamei shrimp fed with 10.0% açaí, given support to the idea of bioactive molecules (as astaxanthin) transference from açaí pulp to the shrimp. ...
Article
Saxitoxin (STX) is a neurotoxic cyanotoxin that also generate reactive oxygen species, leading to a situation of oxidative stress and altered metabolism. The Amazonian fruit açaí Euterpe oleracea possesses a high concentration of antioxidant molecules, a fact that prompted us to evaluate its chemoprotection activity against STX toxicity (obtained from samples of Trichodesmium sp. collected in the environment) in the shrimp Litopenaeus vannamei. For 30 days, shrimps were maintained in 16 aquaria containing 10 shrimps (15% salinity, pH 8.0, 24°C, 12C/12D photoperiod) and fed twice daily with a diet supplemented with lyophilized açaí pulp (10%), in addition to the control diet. After, shrimps (7.21 ± 0.04 g) were exposed to the toxin added to the feed for 96 h. Four treatments were defined: CTR (control diet), T (lyophilized powder of Trichodesmium sp. 0.8 μg/g), A (10% of açaí) and the combination T+A. HPLC analysis showed predominance of gonyautoxin-1 concentrations (GTX-1) and gonyautoxin-4 concentrations (GTX-4). The results of molecular docking simulations indicated that all variants of STX, including GTX-1, can be a substrate of isoform mu of the glutathione-S-transferase (GST) enzyme since these molecules obtained similar values of estimated Free Energy of Binding (FEB), as well as similar final positions on the binding site. GSH levels were reduced in muscle tissues of shrimp in the T, A, and T+A treatments. Increased GST activity was observed in shrimp hepatopancreas of the T treatment and the gills of the A and T+A treatments. A decrease of protein sulfhydryl groups (P-SH) was observed in gills of shrimps from T+A treatment. A reduction in malondialdehyde (MDA) levels was registered in the hepatopancreas of the T+A treatment in respect to the Control, T, and A treatments. The use of açaí supplements in L. vannamei feed was able to partially mitigate the toxic effects caused by Trichodesmium sp. extracts, and points to mu GST isoform as a key enzyme for saxitoxin detoxification in L. vannamei, an issue that deserves further investigation.
... White shrimp (Penaeus vannamei) is a favorite among consumers worldwide because of its flavor, odor and nutritional value. Preserving protein, lipid and moisture contents (Zhang et al., 2015). These compounds attract the rapid growth of pathogenic bacteria such as Staphylococcus aureus, Listeria monocytogenes, and Escherichia coli O157:H7, as well as spoilage bacteria including Pseudomonas spp., Enterobacteriaceae, and Shewanella putrefaciens (Mastromatteo et al., 2010). ...
... In this research, nanoparticles doped on 4A z caused the gradual release of antimicrobial materials from nanocomposite films over 12 days. Furthermore, it should be noted that nutrient deficiency, Eh potential reduction, and growth of other microbial flora all have negative impacts on the growth rate of Pseudomonas species (Madhumitha et al., 2015;Zhang et al., 2015) which our results are consistent with them. Rashid (2018) properties against Pseudomonas spp. ...
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... www.nature.com/scientificreports/ In addition to being the bio-indicator of microbial contamination, the coloration and appearance of the muscle of shrimps reflect the pathogen composition, which is primarily correlated to food safety [19][20][21] . Based on the 16S rRNA gene amplicon sequencing of the muscle of Li. vannamei from the third feeding test, the abundance of the 4 dominant species detected included V. cholerae, V. vulnificus, Pseudomonas oleovorans and Ph. ...
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... Muralisankar et al. (2014) reported that the dietary supplementation of zinc oxide nanoparticles (60 mg kg −1 ) enhanced the growth, survival, and immunity of freshwater prawn M. rosenbergii, and the excessive level of Zn decreased the digestive enzyme activities. Previous studies demonstrated that the dietary Zn reduced the growth of Pacific white shrimp (Litopenaeus vannamei, Zhang et al. 2015) and grass shrimp (Penaeus monodon, Shiau and Jiang 2006). Bajaj et al. (2011) stated that higher or lower level of selenium (Se) can be toxic to the environment and it is called as double-edged sword. ...
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... It was determined by a TA/36R texture analyzer with the probe model TA/36R (Shanghai Baosheng Industrial Development Co., Ltd.). The texture profile was analysed at room temperature of 25 °C, following the method described by Zhang et al. [46]. ...
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Tomatoes have inadequate salability due to their highly perishable nature and water content, leading to massive post-harvest losses during transportation and storage. However, edible coatings have the potential to maintain quality and prolong shelf life. Due to characteristic permeability to volatiles, poor mechanical, thermal, and chemical properties, accompanied by high costs, existing biomaterials have been limited. This study attempts to evaluate the use of chitosan coatings obtained from dung beetle on the shelf life and overall quality of stored tomatoes. The chitosan from dung beetle can be manipulated to form a chitosan-melanin complex. Physicochemical characterization of chitosan flms from dung beetle and crab were mainly performed by scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), and measurements of contact angle. The results showed that chitosan flms from dung beetle presented outstanding biomechanical characteristics such as tensile strength, elongation at break, swelling rate, and high hydrophobicity. Fresh tomatoes coated with 1.0%, 1.5%, and 2.0% chitosan solution from dung beetle, 1.0% chitosan solution from crab, and uncoated fruits were stored at room temperature for 16 days. Chitosan-coated tomatoes were frmer, and showed a decrease in weight loss and decay percentage, along with an increase in ascorbic acid, total sugar, and titratable acid compared to uncoated tomatoes. We concluded that tomatoes coated with 1.0% chitosan solution maintained quality and improved storability better than control samples. Furthermore, chitosan from dung beetle was more suitable as a food preservative than crab chitosan.
... Thus, this method may not efficiently protect shrimp and could easily lead to a decrease in quality of the final products. In addition, bacterial contamination, especially psychrophilic bacteria, cannot be completely suppressed or inactivated by the freezing process or the water-ice-glazing treatment (Zhang, Ma, Deng, Xie, & Qiu, 2015). ...
Article
The combined effect of sodium erythorbate, stable chlorine dioxide, and gellan gum glazing on quality of peeled shrimp was investigated during frozen storage, and compared with traditional water‐ice‐glazing treatment. Data revealed that the growth of total aerobes, Escherichia coli, and Staphylococcus aureus was significantly inhibited in the combined treatment, compared to the water‐ice‐glazing group. Examination of tissue texture and microstructure verified that the combined glazing effectively maintained springiness and chewiness of the shrimp muscle, and this treatment showed a positive effect on stability and integrity of tissue microstructures. Myofibrillar protein content and Ca2+‐ATPase activity in muscle treated with combination were significantly higher than the water‐ice‐glazing treatment. SDS‐PAGE results confirmed that this treatment markedly slowed the degradation of muscle proteins. Additionally, the combined treatment significantly decreased the amount of protein carbonyls and dityrosine, which was mainly governed by the anti‐oxidization effect of incorporated sodium erythorbate. Ice‐glazing is a surface coating process and is especially useful in the field of shrimp preservation, which prevents incidence of surface drying and dehydration, freezer burn, oxidation, and/or rancidity. However, the traditional water‐ice‐glazing can lead to cracking and sublimation during long period of frozen storage. The bacterial contamination cannot be completely suppressed or inactivated by the single ice‐glazing treatment. Among glazing processes, chitosan‐based glazings have been most widely studied to maintain quality of shrimp products. However, chitosan is water‐insoluble, relatively expensive, and highly viscous, which greatly limits its practical applications. For these reasons, alternative treatments that can form a stable and uniform glaze on surface of shrimp should be considered to minimize bacterial contamination and inhibit quality deterioration of frozen products. Outcome of the current study provides information regarding an optimum glazing formulation for shelf‐life extension of shrimp during frozen storage.
... The low TVBN content in fresh samples was also agreed with the obtained volatile avor results. 20 Moreover, the signals of sensor 2 (W5S, broad range sensitivity, sensitive to nitrogen oxides) were signicantly (P < 0.05) higher than those of other sensors; nitrogen oxides are considered as the initial volatile compounds in the natural mackerel (0-40 days). However, during the following period (60-100 days), the signal values of sensor 2 decreased, while those values of other sensors (except sensor 6, W1S, sensitive to methane) all increased signicantly (P < 0.05). ...
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The antioxidative effects of κ-carrageenan oligosaccharides (CO) on the stability of proteins and lipids in mackerel fillets were determined during frozen storage. Electronic nose analysis indicated that CO treatments maintained the stability of the overall volatile flavor profiles in frozen mackerel. Protein oxidation analysis suggested that the incorporation of CO significantly retarded the rapid decrease of Ca²⁺-ATPase activity and active sulphydryl (A-SH) contents while also effectively inhibiting the increases in carbonyl content and surface hydrophobicity of myofibrillar proteins (MPs) compared to the control treatments. Lipid stability results showed that the peroxide values (PVs), conjugated diene (CD) content, anisidine values (AVs), and thiobarbituric acid index (TBA-i) values of the extracted lipids were also clearly reduced by CO treatments during frozen storage. Fatty acid composition determinations further confirmed that the permeated CO molecules stabilized the polyunsaturated C22:6n3 (DHA) in the lipids, most likely due to their efficient free radical scavenging activities.
... For very delicate and highly perishable seafood products such as squids and shrimps, EFW is also used in the form of ice or ice-glazing. Zhang et al. (2015) revealed that forming an ice-glaze on shrimps from SAEW prolonged storage time of shrimp to 80 days, compared with only several hours achieved with individual SAEW application. It was believed that the phase change played a vital role in stabilizing active ions and dissolved hydrogen responsible for 1 -2 log CFU/g reductions in S. aureus and TAB, the inhibition of muscle structure degradation and lipid oxidation. ...
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Meat and seafood products present a viable medium for microbial propagation, which contributes to foodborne illnesses and quality losses. The development of novel and effective techniques for microbial decontamination is therefore vital to the food industry. Water presents a unique advantage for large-scale applications, which can be functionalized to inactivate microbial growth, ensuring the safety and quality of meat and seafood products. By taking into account the increased popularity of functionalized water utilization through electrolysis, ozonation and cold plasma technology, relevant literature regarding their applications in meat and seafood safety and quality are reviewed. In addition, the principles of generating functionalized water are presented, and the safety issues associated with their uses are also discussed. Functionalization of water is a promising approach for the microbiological safety and quality of meat and seafood products and possesses synergistic effects when combined with other decontamination approaches. However, functionalized water is often misused since the active antimicrobial component is applied at a much higher concentration, despite the availability of applicable regulations. Functionalized water also shows reduced antimicrobial efficiency and may produce disinfection by-products (DBPs) in the presence of organic matter, especially at a higher concentration of active microbial component. Utilization should be encouraged within regulated guidelines, especially as hurdle technology, while plasma functionalized water which emerges with great potentials should be exploited for future applications. It is hoped that this review should encourage the industry to adopt the functionalized water as an effective alternative technique for the food industry.
... The muscles of the second abdominal segment were applied to measure changes in texture (hardness and springiness) with a texture analyzer (TMS-PRO, FTC, Sterling, VA, USA). The method used was according to Zhang, Ma, Deng, Xie, and Qiu (2015). Constant test speed, 1.0 mm/s; sample deformation, 30%; hold time between cycles, 3 s; and trigger force, 0.05 N. The average values were of six samples. ...
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.
... [27] TMA showed a significant correlation with storage time. The TMA values increased during the storage time, which took it above the upper limit of consumption on day 9 (5.18 mg N/100g) and is agreed with results found by Okpala et al. [23] Okpala et al. [23] , Dabade et al. [28] and Zhang et al. [29] have reported variable TMA content for shrimps. The increase of TVBN and TMA through time was in agreement with the microorganism activity during storage. ...
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This study aimed to develop a Quality Index Method (QIM) for ice stored Metapenaeus affinis, and estimate its shelf life of shrimp during 12 days of storage analyzing periodically microbiological (total mesophilic (TMC), psychrotrophilic (PTC), physicochemical (TVB-N, TMA, pH, TBARS and FFA), and sensory (Quality Index Method protocol) characteristics. Partial least squares (PLS) regression was used to correlate the QIM attributes, and linear regression analysis was used to check the variables as a function of storage time. Principal component analysis (PCA) was used for interpreting physicochemical and bacteriological quality parameters. The QIM scheme was developed based on 18 demerit points, in which zero indicates total freshness. From the integration of sensory, microbiological, and physicochemical data, it was possible to estimate that the shelf life of ice stored Metapenaeus affinis is 9 days.
... Different authors have reported variable TMA content for shrimps. Dabadé et al. (2015) reported an initial TMA value of 2.5 mg/100 g for Penaeus notialis, 0.33 mg/100 g by Okpala et al. (2014) for L. vannamei and 0.54 mgN/100 g by Zhang, Ma, Deng, Xie, and Qiu (2015). The TMA content varies with species, origin, depth of living, season etc. (Etienne, 2005). ...
Article
To study the effect of temperature in spoilage of Litopenaeus vannamei, fresh shrimps were collected from tropical farm and stored at three different temperatures (30±2 °C room temperature, 4 °C refrigerated and 1 °C ice). Sensory, biochemical and microbial evaluation of the samples were carried out at frequent intervals. The shelf life of the samples was estimated as 10 hrs, 12 days and 16 days at room temperature, refrigerated and ice storage respectively. In ice storage, total volatile base nitrogen values increased at the initial days, followed by a decrease, and again with an increase in value. Leaching out of ammonia by the melt water is considered as the probable reason. Fitness of three Relative Rate of Spoilage (RRS) models was checked to determine the shelf life of L. vannamei, and Arrhenius model was found to be more fitting. Spoilage potential evaluation was carried out by screening the bacterial isolates at the time of sensory rejection and the results revealed that many isolates possess high potential for spoilage. The 16SrRNA gene sequencing analysis identified the predominant potential spoilers as: Enterobacter and Acinetobacter at room temperature, Pseudomonas and Aeromonas at refrigerated storage and, Aeromonas and Enterococcus at ice storage.
... Meanwhile, other solutions of EW have been reported and used, such as neutral electrolyzed water (NEW) with a pH value of 7-8, and ORP equal to 750 to 900 mV, produced in a single cell chamber and the anodic solution is mixed with OH − [193]. Slightly acidified electrolyzed water (SAEW) with a pH value of 5-6.5 and ORP of nearly 850 mV [194] is also produced in a single cell chamber by the electrolysis of HCl alone or in combination with NaCl. The most common types of EW currently used for their desirable effects are summarized in Table 4. ...
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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.
... A cor foi determinada em colorímetro Konica Minolta, CM-700d/600d (Sistema CIE L*a*b*), cujo sistema considera as coordenadas L* luminosidade (preto/branco), a* teor de vermelho (verde/vermelho) e b* teor de amarelo (azul/amarelo) (ZHANG et al. 2015). ...
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Neste trabalho, objetivou-se avaliar a qualidade do camarão marinho L. vannamei cultivado em água doce e em salgada, com ênfase nos parâmetros físicos e sensoriais. Para os parâmetros físicos foram realizadas determinações de pH, capacidade de retenção de água (CRA), perda de peso na cocção (PPC), textura e cor (todas em triplicata). Para análise sensorial participaram do teste 30 provadores, de ambos os sexos, com idade variando entre 23 a 49 anos, para avaliar os camarões segundo os atributos de sabor, odor, cor, textura e suculência e aspecto de preferência geral. Em relação ao pH não houve diferença significativa (p<0,05) entre os dois tratamentos, assim como para CRA e PPC. Os parâmetros de cor (a*, b* e L*) mostraram uniformidade nos resultados, tanto para o camarão in natura como para o cozido, não havendo diferenças significativas. Destacouse a textura que apresentou diferença significativa (p<0,05) entre os tratamentos, com valores de 1,03 a 1,34, corroborando com os dados reportados pela equipe sensorial. Os parâmetros sensoriais analisados não diferiram significativamente, com exceção para os atributos de odor e cor, que foram superiores para o camarão cultivado em água salgada. Apesar disso os dois tratamentos apresentaram qualidade sensorial, física e química satisfatórias.
... 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. ...
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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.
... Samples treated by UST (3.42) had the minimal differences from fresh samples (3.67). During the air thawing processes, the water lost form muscle resulted in the water attaching to the muscle surface, which caused the increase in the L*-value [32]. In addition, part of the pigment taken away as the loss of water during the thawing processes might be a factor that lead to the decrease in a*-value and the increase in b*-value. ...
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The aim of the study was to evaluate the positive effect of ultrasound-assisted saline thawing (UST) on the technological properties (water mobility, water holding capacity, colour, pH, shear force, TVB-N, oxidation reaction and microstructure) of mirror carp (Cyprinus carpio L.). The results present in the study showed that different thawing methods had negative impacts on the quality of mirror carp to varying degrees. Among them, UST samples had significant lower thawing loss, centrifugal loss and cooking loss than ultrasound thawing (UT) and air thawing (AT) samples (P < 0.05). The analysis result of low-field nuclear magnetic resonance illustrated that UST inhibited the mobility and distribution of water effectively. Decrease in shear force and TVBN values were observed in all thawing samples, and the UST samples maintained the significant better texture property and freshness than UT and AT samples did (P < 0.05). In addition, the treatment of UST obtained 1% salt concentration inhibited the oxidation reactions effectively. Investigation of the microstructure of samples demonstrated that the treatment of UST kept the relatively complete structure of tissue than other thawing methods. Therefore, UST can be an alternative strategy to the traditional thawing of meat.
... No negative effects were found. [116] Raw trout Acid electrolyte oxidising water (pH 2.30 and free chlorine 38 ppm), sterile distilled water was tested for 0 (control), 1, 3, 5 and 10 min at 22 • C. ...
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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.
... TVBN content in half-shell mussel muscle was determined using a steam-distillation of trichloroacetic acid (TCA)-mussel extract, according to the report by Zhang et al. [17]. The TVBN extract of mussel samples in 0.60 mol/L TCA solution was loaded into a steamed Kjeldahl-type distillation tube and then absorbed by 0.50 mol/L boric acid solution. ...
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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.
... A texture analyzer (TMS-Pilot, FTC), used to evaluate the texture (hardness) of tuna samples, was utilized according to a previously described method (Zhang et al., 2015). The texture profile analysis (TPA) was performed as follows: sample deformation, 40%; constant test speed, 1.0 mm/s; hold time between cycles, 5 s; and trigger force, 1 N. Hardness was defined as the maximum force (N) that occurs at the first compression cycle. ...
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We investigated the effect of squid Maillard peptides (SMPs) on the shelf life and quality of shrimp for 20 days. Water‐soluble chitosan coatings incorporated with SMPs (SMPs + chitosan) were applied to shrimp under chilled conditions. Untreated samples were used as control, along with samples treated with water‐soluble chitosan and SMPs alone. The pH increase was observed in all samples, as well as increased total plate count, total volatile basic nitrogen, peroxide value, and thiobarbituric acid index. However, these indexes in the SMPs + chitosan group were lower than the other three groups, which suggested SMPs + chitosan might play a role in retarding quality loss of shrimp, and there might be a combined effect between water‐soluble chitosan and SMPs. Based on hardness, springiness, and sensory evaluation, shrimp coated with SMPs + chitosan was the best preserved, with a shelf life of 16 days but only 8–12 days for other samples. The present work demonstrates the effectiveness of SMPs + chitosan, offering a promising alternative to inhibit microbial growth and lipid oxidation on shrimps during refrigerated storage. This study investigated the effect of chitosan coating combined with squid Maillard peptides (SMPs + chitosan) on the quality of Pacific white shrimp during iced storage. The SMPs + chitosan treatment was found to provide superior preservation of shrimp than either of the two components alone or the control. In addition, a possible synergistic effect between SMPs and chitosan, leading to inhibition of shrimp quality loss, was observed.
... A similar relationship was found for the FRAP data. However, the values for TBARS indicated the decrease in quality of shrimp, which was due to the formation of lipid oxidizing products (e.g., aldehydes produce off flavors) (Chaijan et al., 2006;Zhang et al., 2015) This high absolute r value indicated that retardation of both melanosis and lipid peroxidation were attributed to the high phenolic content in the extracts. Phenolic compounds might chelate the metal pro-oxidants in shrimp muscle and that resulted in the delay of lipid oxidation in shrimp (Abbasvali et al., 2016). ...
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Melanosis in shrimp usually leads to reduction in its shelf life and quality, which causes a significant loss in economic value of shrimp products. This study reports potential applications of nine ethanolic extracts of by-products, i.e., peel and/or seed from three Vietnamese avocado varieties as effective inhibitors of melanosis in whiteleg shrimp. Six out of nine shrimp samples treated with the prepared extracts (0.025%, w/v) reduced melanosis and lipid oxidation more significantly as compared to those treated with sodium metabisulfite (SMS, 1.25%, w/v) and control groups (treated with water) during 8-day storage at 4°C (P<0.05). These six extracts had mean gray values ranging from 47.0±0.7 to 57.3±0.4% were lower than those treated with SMS (mean gray of 39.8±0.4%). The inhibition of melanosis and lipid oxidation in shrimp for these extracts could be attributed to their high content of polyphenols [total phenolic content (TPC) from 44.5±1.1 to 144.7±1.9 mg gallic acid equivalents/g dried weight] and strong antioxidant activities [including 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, ferric reducing antioxidant power (FRAP), and tyrosinase enzyme inhibition]. Pearson statistical analysis showed strong correlation for melanosis inhibition to TPC and DPPH scavenging (r>0.80) followed by tyrosinase inhibition and FRAP (r>0.50). The findings obtained from this study suggest potential utilization of avocado by-product extracts as safe and cheap natural alternatives to traditional sulfites for anti-melanosis and shelf life extension of whiteleg shrimp.
... Effects of the thawing methods on the surface hydrophobicity of myofibrillar protein in from swimming crabs Surface hydrophobicity is a sensitive index that can be used to determine the changes in the fine structure of proteins and reflects the relative content of hydrophobic amino acids on the protein surface. This parameter is closely related to physicochemical and functional properties, such as water retention of the protein (Chelh et al., 2006;Kong et al., 2013;Zhang et al., 2015). In this experiment, the amount of bromophenol blue that bound was used to reflect the surface hydrophobicity. ...
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This study compared the effects of conventional thawing methods (water immersion thawing (WIT, (25±1) °C), natural air thawing (AT, (25±1) °C, relative humidity (RH) (65±2) per cent), refrigerator thawing (RT, 4 °C, RH (80±2) per cent) and low-temperature (LT) combined with high-humidity thawing (LT, –1 °C to 1 °C (LT–1–1), 2–4 °C (LT2–4), 5–7 °C (LT5–7) and 8–10 °C (LT8–10), RH≥95 per cent) on the water-holding capacity, lipid oxidation and biochemical properties of Portunus trituberculatus (P. trituberculatus) myofibrillar protein. The results showed that WIT and AT significantly decreased the water-holding capacity while dramatically increasing lipid oxidation, protein oxidation and degeneration, resulting in serious P. trituberculatus quality deterioration. High humidity was beneficial for P. trituberculatus thawing. The thawing time of P. trituberculatus under the conditions of LT2–4 was only 39.39 per cent of that of conventional air thawing at 4 °C (RT), and the LT2–4 samples not only maintained better water-holding capacity but also had an obviously reduced degree of lipid oxidation, protein oxidation and denaturation. Thawed samples LT2–4 and LT5–7 provided better maintenance of P. trituberculatus quality than the LT–1–1 and LT8–10 samples. The best quality was exhibited after thawing at 2–4 °C. The levels of thiobarbituric acid reacting substances, carbonyl content and surface hydrophobicity observably decreased in these samples, while the total sulfhydryl contents dramatically increased compared to those of conventionally thawed samples, indicating lower lipid oxidation and protein oxidation. Moreover, the Ca2+-ATPase activity of the sample thawed at 2–4 °C (2.06 μmol Pi/mg prot/h) was markedly higher than that of samples subjected to WIT and AT. The product qualities observed after thawing at –1 °C to 1 °C, 5–7 °C and 8–10 °C under LT were comparable to that observed by RT. Considering its thawing efficiency and product quality, LT is a suitable method for the thawing of P. trituberculatus, and the ideal thawing conditions were LT at 2–4 °C.
Article
Background In this paper, the changes in free astaxanthin (F‐AST) and astaxanthin esters (AST‐E) in L. vannamei during iced storage and frozen storage were investigated. The liquid chromatography‐atmospheric pressure chemical ionization‐tandem mass spectrometry (LC‐APCI‐MS/MS) method was used to quantify molecular species of AST‐E in shrimp during storage. RESULTS Based on the analysis of auto‐oxidation products, apo‐12‐astaxanthinal and apo‐13‐astaxanthinone DHA ester were identified as the major oxidation products of F‐AST and AST‐E in L. vannamei during storage. The total astaxanthin (T‐AST) content decreased by 34.51% after 7 days in iced storage. In contrast, the content of T‐AST decreased by 43.76% after 12 weeks in frozen storage. The content of F‐AST decreased by 29.99% while 13‐cis‐astaxanthin increased after 3 days in iced storage, which indicated that degradation of AST was accompanied by isomerization. TVB‐N and T‐AST content showed a significant negative correlation while in frozen storage, where the concentration of T‐AST might be one indicator to evaluate shrimp freshness. Conclusion The correlation coefficients between phenol oxidase, lipoxygenase, apo‐12‐astaxanthinal, and apo‐13‐astaxanthinone DHA ester were all greater than 0.97 (p < 0.01). This correlation indicates that PO and LOX were the main internal factors to improve oxygenation of AST in L. vannamei. These results provide a theoretical basis for further study of oxidation and the degradation mechanism in AST, as well as a new idea for the development and utilization of AST compounds in Pacific white shrimp. This article is protected by copyright. All rights reserved.
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The enzymatic oxidation process that causes black spots on shrimp, named melanosis, leads to spoilage and economic losses. Therefore, there is an urgent need for strategies to reduce melanosis in the food industry. Cold plasma is an emerging nonthermal food processing technology. This work explores a novel application of cold plasma for the preservation of shrimp quality. This study aimed to evaluate the effects of cold plasma on the quality attributes of Pacific white shrimp (Litopenaeus vannamei). The shrimp samples were divided in two groups: the control group and the plasma group. Samples were exposed to nonthermal plasma for 10 min at a frequency of 500 Hz. Microbiological assays, including total counts of mesophilic and psychrotrophic bacteria, Staphylococcus spp., and Salmonella sp., were performed along with investigations of physicochemical parameters, such as pH, color, water-holding capacity, cooking loss, and shear force. In addition, sensory (quality index method) tests were conducted. The plasma group exhibited a shelf life of 14.07 days, while the control group exhibited a shelf life of 9.78 days. The experimental protocol used in this study was not enough to obtain significant reduction in the bacterial load. However, treatment with the cold plasma contributed to improving the physicochemical properties during storage. HIGHLIGHTS
Article
To study and predict quality changes of Pacific white shrimp (Litopenaeus vannamei) during storage at different temperatures (273, 276, 279, 282, and 285 K), changes in quality of sensory assessment (SA), total aerobic counts (TAC), total volatile basic nitrogen (TVB-N), and K-value were determined. An Arrhenius model and a radial basis function neural network (RBFNN) model were built to predict quality changes of Pacific white shrimp, and the relative performances between the two models were compared. For the Arrhenius model, SA and K-values showed good performance in first-order reactions, while TAC and TVB-N showed good performance in zero-order reactions. The relative errors of the RBFNN model for all indicators were within 10%, but the range of relative errors based on the indicators of SA, TAC, TVB-N, and K-value were 1.68–81.20%, 5.54–25.50%, 2.58–71.06%, and 3.66–48.39%, respectively, for the Arrhenius model. Thus, the RBFNN model was more effective for predicting quality changes of Pacific white shrimp during storage between 273 and 285 K.
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.
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The effect of theaflavin pretreatment on changes in quality of semi-dried large yellow croaker fillets was investigated and compared with a water-soaking treatment during storage. The data indicated that the springiness, chewiness, L*, and b* values of the control and theaflavin-treated fillets both showed significantly decreasing trends during 5 days of room-temperature and 40 days of chilled storage. However, the incorporation of theaflavins exhibited positive effects on the texture and color stability of the fillet samples. Importantly, the antioxidant theaflavin treatment significantly inhibited the rapid increase of the TVBN content, reduced the peroxide and thiobarbituric acid index values, and slowed the changes in the myofibrillar carbonyls and surface hydrophobicity during storage when compared with those of the water-soaking treatment. Additionally, histological observations verified that the theaflavins showed pronounced effects on the stability of myofibrillar proteins (MPs) and remarkably inhibited MP and lipid oxidation during the two types of storage.
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Organic fouling was one of the most fatal weakness for membranes applied in water treatment. Aiming at overcoming the defect of liable to contamination and achieving efficient circulation and long-term stable operation, it was reported a kind of multilayer-loaded hydrogels membranes with superior antifouling property. Hydrogel coating mixture were coated onto PES substrate layer by layer and then cross-linked by ambient free radical blending polymerization reaction endowing the membrane with interpenetrating network structure and super hydrophilic surface. The FT-IR, FESEM, and AFM were used to character the structure and morphology of obtained membranes. Dynamic contact Angle, BET and membrane performance evaluation instrument were used to evaluate the membrane performance. Compared with quantitative single layer-coated membrane, the four layers-coated hydrogel membrane exhibited more excellent and stable performance in terms of flux, rejection and fouling resistance. In particular, the water flux of the four layers-coated hydrogel membrane increased by about 25%. When 0.5 g/L BSA was selected as simulated protein contamination liquid, flux recovery rate (FRR) of four layers-coated hydrogel membranes was up to 86.33%, indicating excellent long-term tolerance and resistance to proteins. It must be pointed out that four layers were the maximum loading number of the ambient self-crosslinking hydrogel CQAS casting solution within the limit air-cured time. On the whole, the multi-layer coated hydrogel membranes showed practical application value in the field of water treatment.
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Large yellow croaker (Larimichthys crocea) has rich protein content and high economic value, but has a short shelf life. Lipopeptides extracted from marine Bacillus megaterium were applied to the preservation of large yellow croaker and effectively increased the shelf life of large yellow croaker. The results showed that the total viable count (the total number of colonies), total volatile base nitrogen, texture and other indicators in the treatment groups were better than control and the difference was significant (p < .05). Furthermore, bacillomycin D with 14 and 15 carbon atoms in β‐amino fatty acids was separated from the lipopeptides and it was used to study its inhibitory effect on Aspergillus flavus, and the minimum inhibitory concentration and minimal fungicidal concentration were 50 μg/mL and 200 μg/mL, respectively. Bacillomycin D significantly inhibited the spores germination, mycelial growth, and sporulation of A. flavus. The results of scanning electron microscopy and transmission electron microscopy showed that the morphology of A. flavus was changed, and cell contents was leak after treatment with bacillomycin D. Practical applications Marine B. megaterium suspension and lipopeptides extracted from the strain of marine B. megaterium were applied to the preservation of large yellow croaker, and it laid the foundation for studying more potential effects of lipopeptides. Furthermore, in this study, bacillomycin D was separated from lipopeptide and it was identified 14 and 15 carbon atoms in β‐amino fatty acids. It was well‐stabilized and could later be used as preservative for large yellow croaker. The preliminary application of the preservation of large yellow croaker had proved that lipopeptides have a good development and application prospect as a new type of aquatic preservative.
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Direct current (DC) plasma nitriding offers some disadvantages, especially in parts with complex geometries, where the presence of edges is significant, such as gears, molds, and needle punched parts are strongly affected by this effect, leading to irregular formation of nitrided layers and high variation in surface hardness. To solve these problems two techniques were developed as alternatives, namely: pulsed plasma nitriding and cathodic cage nitriding. In this work, these three nitriding techniques were compared using AISI 1045 steel as substrate. Steel discs were nitrided with the purpose of evaluating the influence of these different plasma configurations on the characteristics of the nitrided layer. The treatments in the three techniques were carried out at the same pressure, temperature, time and gas atmosphere. The samples were characterized for the microstructure, microhardness and crystalline phases present. X-ray diffraction with grazing incidence was used to verify the order of the nitrites formed and to estimate the thickness of the single-phase layers. Differences between the configurations with respect to the occurrence of restriction rings, total thickness (xε +xγ') and relative (xε/xγ') compound layers were observed.
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A new biofilm, consisting of gelatin and water soluble chitosan (carboxymethyl chitosan) and infused with 0.5 mg/mL squid Maillard peptides (F-SMP), was tested as preservative for bluefin tuna stored at 4 ± 1 °C for 10 days. Unwrapped samples were used as control, along with samples wrapped in polyethylene and gelatin-water soluble chitosan films without squid Maillard peptides. Weight loss was observed in all samples, as well as increased hardness, total plate count, total volatile basic nitrogen, peroxide value, and thiobarbituric acid index. The histamine, tyramine and cadaverine concentration in tuna slices increased during storage. In the F-SMP group the concentrations were lower than the other three groups, which were consistent with the total plate count results and suggest that low total plate count could reduce production of biogenic amines. Based on redness, metmyoglobin content, appearance, and sensory evaluation, tuna slices wrapped in F-SMP were the best preserved, with a shelf life of 8 days but only 2–4 days for other samples. The data suggest that the F-SMP effectively inhibit microbial growth and lipid oxidation, and efficiently preserve tuna slices.
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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.
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The objective of this study was to evaluate the effects of the number of freeze-thaw (F-T) cycles on moisture migration, protein degradation, microstructure and quality in Litopenaeus vannamei. The quality of samples with different F-T cycles were determined by low-field nuclear magnetic resonance (LF-NMR), magnetic resonance imaging (MRI) and scanning electron microscopy (SEM), combined with sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), texture properties analysis (TPA), color difference, polyphenol oxidase (PPO) activity, total volatile basic nitrogen (TVB-N), total viable count (TVC), and sensory evaluation. The results showed that F-T cycles caused a significantly increase in transverse relaxation time in T22 and T23 and a decreased brightness of pseudo-color diagram after 4 F-T cycles, indicating that water mobility increased as immobilized water was shifted to free water. The texture of samples declined as well, especially after 4 F-T cycles. The rapid growth of PPO activity caused a decrease in brightness (L*) and an increase in redness (a∗) after 3 F-T cycles. The increase of TVB-N, TVC, and sensory score explained the changes in shrimp quality which became obvious after 3 F-T cycles and unacceptable after 6 cycles. Meanwhile, fewer than 4 F-T cycles accelerated protein aggregation, while denaturation occurred after 4 cycles. Therefore, repeated F-T cycles could accelerate the changes of protein, microstructure, water distribution, and quality deterioration especially after 3 F-T cycles, with a threshold was 6 F-T cycles.
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Aim: The present study aimed to investigate the shelf life of Pacific white shrimp (Litopenaeus vannamei) reared in inland saline water (ISRV) with those reared in natural brackish water (BWRV) during ice storage. Methodology: Freshly harvested L. vannamei shrimp cultured in inland saline water and brackish water were collected and biochemical parameters, microbial analysis and sensory parameters were evaluated for 21 days during ice storage with sampling interval of 3 days. Results: Total volatile basic nitrogen content increased up to 9th day in shrimps reared in BWRV and up to 3rd day in ISRV reared shrimps. Similarly, tri methyl amine content increased up to 3rd day for ISRV, there after the values decreased. The values of lipid oxidation such as peroxide value, free fatty acid and thiobarbituric acid reactive substance increased. Sensory scores for ice stored BWRV and ISRV showed a decreasing trend with increasing storage period. Interpretation: On the basis of microbiological parameters, pacific white shrimp (Litopenaeus vannamei) reared in brackish water and inland saline water can be ice-stored up to 12 days in fresh conditions, while other biochemical and sensory parameters are acceptable up to 18 days.
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We investigated the effects of chitosan‐based coatings on the preservation quality of refrigerated Chinese shrimp for 12 days. Samples of Chinese shrimp were subjected to three different coating treatments, namely chitosan (CH), chitosan and ε‐polylysine (CH + ε‐PL), chitosan combined with ε‐polylysine and carrageenan (CH + ε‐PL + CA), and compared with a control. The bacteriological characteristics [total viable count (TVC)], chemical indexes including pH, thiobarbituric acid (TBA) value, K‐value, and total volatile basic nitrogen (TVB‐N), texture (hardness, chewiness, and elasticity), and sensory changes were assessed. The increases in TVC, pH, TBA, K‐value, and TVB‐N were observed to be delayed by preservation treatments, and the textural and sensory characteristics indicated that the treated shrimp were preserved more effectively than the control. Treatment with chitosan combined with ε‐polylysine and carrageenan was the most effective preservation method than treatment with chitosan alone or chitosan and ε‐polylysine; the shelf life was also prolonged. Therefore, treatment with chitosan combined with ε‐polylysine and carrageenan is proposed as a potential method for shelf life extension of Chinese shrimp for refrigerated storage. The growth of microorganism, decomposition of protein, and oxidation of lipid could be effectively inhibited by chitosan-based coating treatment. Treatment with chitosan combined with ε-polylysine and carrageenan is proposed as a potential method for shelf life extension of Chinese shrimp for refrigerated storage.
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In this paper, remodeling the shrimp processing chain and the effects of the transformation on the biochemical and sensory qualities of fresh Pacific white shrimp ( Penaeus vannamei) under refrigeration storage were investigated. In the proposed model, a dielectric barrier discharge atmospheric cold plasma pretreatment step using a 60 kV source for 60, 90, 120, and 150 s was introduced after the first and second wash followed by refrigeration storage at 4 ± 1 °C for 12 days. Chemical, biochemical, and sensory attributes of the shrimp were monitored and compared with those of shrimp processed through the traditional method without atmospheric cold plasma pretreatment (control). Incorporating minimal dielectric barrier discharge atmospheric cold plasma pretreatment step had more desirable quality outcomes characterized by low malondialdehyde concentration, low volatile nitrogen products content, and comparable proximate composition. Texture, pH, and color were remarkably retained at 120 and 150 s of atmospheric cold plasma pretreatment and protein degradation was negligible up to 90 s than at 120 and 150 s of pretreatment. We conclude that remodeling the shrimp processing chain through incorporating minimal dielectric barrier discharge atmospheric cold plasma pretreatment with key considerations on operation parameters can maximize the beneficial biochemical and sensory quality outcomes while minimizing the negative impacts associated with traditional shrimp processing.
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Refrigerated treatment offers an effective avenue to delay spoilage process of aquatic products during storage, while none or less study has been reported for bivalve species. This work aims to investigate the variations in different storage freshness of frozen razor clam samples, by which an effective evaluation system based on frozen kinetics models was established. In this study, fresh razor clam samples were preserved at the temperature of 268, 258, and 248 K for 40 days, respectively. The spoilage process was determined by a series of freshness assays, including sensory score (SS), electric conduction (EC), total volatile basic nitrogen (TVB-N), K -value, and total colonies counts (TCC). On this basis, the variations in these indexes were fitted by zero-, first- and second- order kinetic models. Results showed that zero -order kinetic model was more suitable to fit each freshness trend. Accordingly, the shelf life of razor clam was predicted as 47∼54, 79∼84, and 121∼154 days when the samples were preserved at 268, 258, and 248 K, respectively. This study revealed the general trends of the frozen decay process of bivalve species, which is instructive to establish applicative models for the real distribution chain.
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The comprehensive effects of slightly acidic electrolyzed water and slurry ice (SAEW‐SI) on growth of microorganisms, physicochemical reaction and sensory attributes of mackerel (Pneumatophorus japonicus) was evaluated during storage at 4°C. The changes of microbiological (total viable counts (TVCs), psychrophilic bacteria counts, pseudomonas bacteria counts, H2S‐producing bacteria counts), physicochemical (pH, total volatile basic nitrogen (TVB‐N), water holding capacity (WHC), thiobarbituric acid reactive substances (TBARS), texture profile analysis (TPA), color difference, adenosine triphosphate (ATP)‐related compounds), protein characteristic (SDS‐PAGE, fluorescence spectroscopy analysis) and sensory evaluation were analyzed. It was observed that the SAEW‐SI treatment had a strong inhibitory effect on microbial growth (5.8 log CFU/g on 24th day). And SAEW‐SI could alleviate the oxidation degree of myoglobin and lipid, thus the color of samples was greatly maintained. According to the sensory attributes, the shelf‐life of samples in SAEW‐SI group increased by 6 days compared to control group. Therefore, SAEW‐SI could be a useful preservation approach for fish industry.
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The effect of citric acid (CA) combined with rosemary extract (RE) on post‐harvest preservation of Pacific white shrimp (Litopenaeus vannamei) during 8 days of chilled storage were investigated. Microbiological (total viable count (TVC), physicochemical (color difference, pH, total volatile basic nitrogen (TVB‐N), thiobarbituric acid (TBA), texture profile analysis (TPA), intrinsic fluorescence intensity (IFI), melanosis) and sensory evaluation of shrimp muscles were all periodically analyzed. Compared to the control, CA and RE treatment alone, results showed that RE and CA had synergistic effects (P<0.05) in inhibiting microorganism growth, lipid and protein oxidation, and maintaining sensory and texture profile. CA combined with RE treatment prolonged the shelf life of Pacific white shrimp up to 8 days of storage at 4 ± 1°C. The results indicated that samples immersed in CA combined with RE suggested a promising approach for the preservation of Pacific white shrimp.
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Extensive use of chemicals in food processing and packaging attracted the public attention because of serious health problems. Hence, the application of inorganic antimicrobial compounds can be a safe and potential approach in this regard. In this study nanocomposite films containing NPs of three metallic oxides alone i.e. SiO, ZnO and CuO or in combinations i.e. SiO-ZnO, SiO-CuO, ZnO-CuO supported by 4A zeolite (4A z) were evaluated for their antibacterial potential to manage the microbial load in both raw and inoculated refrigerated shrimp. The antibacterial potential of NPs doped on 4A z determined through well diffusion method, MIC, MBC, FIC and %live/dead proportion, indicated strong activity of NPs against a range of food born and pathogenic bacteria i.e. Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, Pseudomonas fluorescens, Vibrio parahaemolyticus and Aeromonas caviae. Nanocomposite films containing NPs were also found active against the in vitro growth of these bacteria. It was shown that nanocomposite film having NPs significantly reduced the total viable, Shewanella putrefaciens, Enterobacteriaceae and Pseudomonas spp. count in raw shrimp and L. monocytogenes, S. aureus and E. coli count in inoculated shrimp as well as exhibited higher scores for sensory evaluation as compared to control. Generally, the treatment SiO-ZnO NPs was more effective than other treatments while the CuO NPs was least effective. From these results it is concluded that nanocomposite films, by limiting chemical use, could act as novel, low cost, safe and effective packaging approach for microbial management as well as enhancing the shelf life of refrigerated shrimp.
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Increasing fishery product shelf‐life is the main concern regarding to aquatic productions. The aim of this study is to examine the effect of saffron Nano‐emulsion on shelf‐life of shrimp using two methods of spontaneous emulsification (SP) and ultrasonic homogenization (US). Shrimps were divided into 3 groups. In each group, saffron was either 3.0 or 5.0 %, produced either through US or SP methods and kept at 4 or 8 °C. Antimicrobial activity, oxidative activity and pH of samples were evaluated. US/3% Nano‐emulsions showed the highest antimicrobial activity. The lowest pH values were observed in US/5%/4 °C and SP/5%/4 °C. All treatments in day 7 and 14 had pH value of 8±0.008. PV increased in all subgroups. The amount of peroxide in samples treated by 5% emulsion decreased. TBA value showed the same trend as PV. The results demonstrated that 5% saffron Nano‐emulsion produced by US method manifested better protective effects.
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This paper studied the effect of modified atmosphere packaging (MAP) with 40–80 % CO2, 5 % O2 and 15–55 % N2 on the quality of Pacific white shrimp (Litopenaeus vannamei) during 10-day storage at (4 ± 1) °C. The effect of CO2 on the shrimp quality was compared by analyzing the quality indices such as total viable counts (TVC), total volatile basic nitrogen (TVB-N), pH and polyphenoloxidase (PPO) activity, whiteness and sensory attributes. Changes in myofibril length of shrimp flesh were also studied, which correspond to flesh softening. The findings suggest that the shrimp packaged in modified atmosphere had better quality indices than the control. Compared the MAP-batches, 80 % CO2/15 % N2/5 % O2 led to the lowest level of TVC, TVB-N values, PPO activity and the highest sensory scores. Therefore, high-CO2 packaging should be recommended to delay quality loss of shrimp during transportation and storage.
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Shrimp are an important commodity in the international fisheries trade and there is an indication of an increase in worldwide consumption of this crustacean. Salmonella and Listeria have been isolated from shrimps and shrimp products on a regular basis since the 1980s. The continued reporting of the presence of these pathogens in fresh and frozen shrimps, and even in the lightly preserved and ready-to-eat products, indicates that the existing practices used by the manufacturers or processors are insufficient to eliminate these pathogens. This paper reviews the information available on Salmonella and Listeria in shrimp and makes recommendations on control options and avenues for future research in order to improve shrimp safety and quality.
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A simple, rapid and inexpensive method is proposed for determination of trimethylamine (TMA) in fish muscle. This procedure includes a deproteinization step with trichloroacetic acid (TCA) followed by blocking of primary and secondary amines using formaldehyde at alkaline pH and finally steam distillation of TMA. No statistically significant differences were found between this new optimized procedure and either the Conway microdiffusion method or the colorimetric method. Using the technique proposed here it is possible to assay both the total volatile basic nitrogen (TVBN) and the TMA in less than 30 min.
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Ice-glazing is applied to protect the frozen shrimp from undesirable quality changes during frozen storage. Effects of initial frozen shrimp temperature on glaze uptake; glazing time on glaze uptake; and different glaze percentage on physical and chemical changes of frozen shrimp during storage were investigated. Shrimps were frozen in a spiral freezing machine (�35 �C/15 min); transferred to the air blast freezer until the core temperature reached �18 �C, �25 �C and �30 �C; submitted to glazing process; and stored at �18 �C for 180 days. The glazing percentage, pH and N-TVB levels were monitored every 45 days. This study has demonstrated the effectiveness of the glazing process as a protecting agent for frozen shrimp. A reasonable range of water uptake could be between 15% and 20% to guarantee the final quality. Therefore, it is important to prevent temperature fluctuations during transportation and storage to maintain the quality of the frozen shrimps.
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This study investigated growth of enterotoxin-producing Staphylococcus aureus and time–temperature combinations needed for enterotoxin production in pre-cooked tuna meat. Frozen samples (50 ± 5 g) of pre-cooked albacore tuna (loin, chunk and flake) and skipjack tuna (chunk and flake) were thawed overnight at 5–7 °C, inoculated with five strains of S. aureus (2–4 log CFU/g), and incubated at 37 and 27 °C for up to 36 h. Changes of S. aureus populations in samples during incubation were determined by plating on Baird–Parker media. Results indicate that increases in S. aureus populations varied among the 5 types of tuna samples. Incubation at 37 °C for at least 6 or 8 h was required to allow an increase in S. aureus populations by >3 log CFU/g in inoculated albacore or skipjack tuna meat. A similar increase of S. aureus counts (>3 log CFU/g) in albacore and skipjack samples required more than 8 and 10 h, respectively, when samples were incubated at 27 °C. No enterotoxin was produced in albacore or skipjack tuna meat inoculated with five strains of enterotoxin-producing S. aureus and exposed to 37 °C for 12 h or 27 °C for 16 h. All the samples showed clear sign of spoilage before enterotoxin was detected.
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The aim of this research was to compare the effect of chitosan solutions on frozen salmon preservation with that of water glazing. For this purpose, three chitosan solutions (0.25%, 0.50% and 0.75% w/v) and water were applied in different amounts (6%, 8% and 11% of coated fillet weight) directly on the surface of frozen salmon. In order to accelerate the deterioration processes, salmon was stored during 14 weeks at −5 °C. Microbial and chemical indices were used to assess deterioration during storage and the coating stability was evaluated through weight loss measurements. The results obtained showed that chitosan coatings can be a good barrier to protect frozen fish from deterioration. Microbial growth, assessed by total viable counts (TVC), and total volatile basic nitrogen (TVB-N) were maintained below the maximum limits recommended which are 5 × 105 CFU/g and 35 mg nitrogen/100 g fish, respectively. The use of 0.50% and 0.75% chitosan solutions generally demonstrated to be more efficient in preventing salmon weight loss.
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The effect of the antioxidant activity of rosemary extract on marinated deep-water pink shrimp (Parapenaeus longirostris Lucas, 1846) stored at 1°C was investigated. Chemical, physical, instrumental, microbiological and sensory analyses were performed to investigate the quality changes and to determine the shelf-life of marinated shrimps. Chemical composition of the shrimp was determined and no significant difference (P>0.05) was found between the control group (without rosemary extract) and the experimental group (with rosemary extract). Both groups contained 2% citric acid. There was no significant difference (P>0.05) between the sensory analysis of control and experimental groups on storage days 0, 15, 30, 45 and 60 while rancidity was noted by the panelists in the control group on day 75. The TBA value of the control group reached the consumption limit on day 75 but it was still 'very good' for the experimental group. Although the bacterial load of both groups were lower than the consumption limits on storage day 75, TBA value limited the shelf-life of the control group but the experimental group was still of good quality for consumption after 75 days. Copyright © 2007 Elsevier Ltd. All rights reserved.
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Shrimps caught at sea were boiled in seawater, air blast or nitrogen frozen, glazed and then packed in plastic bags with a low oxygen transmission rate. The bags were either flushed with nitrogen (modified atmosphere packaging) or with atmospheric air before sealing. The shrimps were then stored for up to 12 months in a freezer cabinet at −17°C with fluctuating temperatures. During storage they were either exposed to fluorescent light or kept in darkness. To investigate the effect of fluctuating temperatures some of the modified atmosphere-packed shrimps were stored in darkness in a cold store at a constant temperature of −18°C. Quality changes were determined by sensory evaluation combined with chemical/physical analyses, including determination of the pigment astaxanthin and measurement of the oxidative stability by determination of thiobarbituric acid-reactive substances (TBARS). Packaging in modified atmosphere resulted in overall better quality in relation to colour fading, development of rancid flavour and toughening of the meat. Light exposure influenced both colour fading and lipid oxidation negatively. Temperature fluctuations resulted in very pronounced formation of frost in the packages. After 6 to 9 months of frozen storage, the amount of frost corresponded to the weight of the glazing layer applied before storage.
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The purpose of this study was to analyse the effect of two gas mixtures, containing 40% CO2/30% O2/30% N2 and 45% CO2/5% O2/50% N2, on the microbiological flora (total bacteria count, H2S-producers microorganisms and enterobacteria) and some biochemical indexes (trimethylamine, total volatile basic nitrogen and biogenic amines) of chilled shrimp. Modified atmosphere packaging (MAP) on shrimps delayed the microbial growth compared to air-packed or iced stored shrimp as well as the trimethylamine and total volatile nitrogen production. However, the production of some biogenic amines seemed to be enhanced during the storage of MAP-shrimp.
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The effects of lighting conditions and the application of natural antioxidants (rosemary extract and ascorbic acid) on the shelf‐life of gilt‐head sea bream fillets (Sparus aurata) packaged in a modified atmosphere (MAP) and stored at 1 ± 1 °C were studied. Lighting with low‐UV colour‐balanced lamps led to an extension of shelf‐life compared with that under supermarket fluorescent tubes, as assessed by lipid oxidation (TBARS value) and sensory evaluation. The application of antioxidants to the surface of MAP fillets delayed lipid oxidation besides improving the sensory quality. Rosemary extract was more effective than ascorbic acid in delaying lipid oxidation under both kinds of lighting. The effect of ascorbic acid was greater in the samples illuminated by low‐UV tubes than in those stored under conventional lighting. However, the effectiveness of rosemary extract was similar in both kinds of lighting conditions. Copyright © 2004 Society of Chemical Industry
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The aim of this study was to investigate the effects of grape seed extracts on inhibition of melanosis in shrimp. Defatted grape seed powder was extracted using ethanol. Dipping solutions in five different concentrations (0, 2.5, 5.0, 10 and 15 g L−1) were prepared using grape seed extract and distilled water. The shrimps were dipped into the solutions and stored at 4 °C. Melanosis was investigated by sensory analysis and lightness, redness and yellowness values were measured by chromometer during the storage for 3 days. According to the results, grape seed extracts showed inhibition effect on the formation of melanosis. The best results were obtained with the solution of 15 g L−1.
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Of the 168 fishery products and 87 samples from fish processing factory workers analyzed, 21 (17%) and 54 (62%) were found positive for enterotoxigenic Staphylococcus aureus, respectively. Among the products, incidence was high in frozen peeled un-deveined (PUD) prawns and frozen fish cutlets (33% each) compared to frozen peeled and deveined (PD) prawns and frozen squids (25% and 20%, respectively). 21 out of 51 strains (41%) isolated from products and in 15 out of 54 strains from processing workers (28%) were found to be enterotoxigenic. The enterotoxin type Staphylococcal enterotoxin C (SEC) (57%) was predominated followed by Staphylococcal enterotoxin A (SEA) (43%) in products and Staphylococcal enterotoxin B (SEB) (40%), Staphylococcal enterotoxin C (SEC) (40%) and Staphylococcal enterotoxin A (SEA) (20%) in workers.
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The effects of sepia ink (Sepia officinalis) extract solutions with concentrations of 0.0%, 0.01%, 0.2% and 2% on the microbial flora and the chemical composition of stored peeled shrimp (Penaeus kerathurus) were examined at two temperatures (−2 and 0 ° C). The quantification of aerobic and psychotrophic bacteria was performed by a plate count after each 3 days of storage. Results showed that partial freezing and coating treatments had synergistic effects in reducing the aerobic plate counts (APCs) with at least a 10-day extension of shelf life. The inhibition efficacy on the psychotrophic cells in shrimp meat increased with the increase in concentration of the added extract. However, the extract showed no effect after 16 days on the mesophilic bacteria. No detrimental effects of sepia coating on organoleptic parameters such as appearance, odour, and taste were observed. Partial freezing reduced significantly the formation of nitrogenous compounds in all samples, however total volatile bases (TVB) and trimethylamine (TMA) levels were lower in the sepia extract-treated samples. Initially, shrimp tissue ninhydrin positive substances (NPS) level was 9.74 ± 1.05 mM/100 g tissue. No significant change was observed in the treated-samples during the refrigerated storage, conversely, these concentrations increased in the raw shrimps.
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The microbiological quality of farm-reared, tropical freshwater prawn (Macrobrachium rosenbergii) stored at 2 different temperatures was studied. The prawn muscle was found to have the initial bacterial load of 104 cfu/g. The lactics and vibrios were in the range of 102 cfu/g, while the E. coli, aeromonads, staphylococci, anaerobes, and molds were in the level of 101 cfu/g. Salmonella and Vibrio cholerae were present in the prawn muscle. The prawn muscle held at room temperature (28 ± 2 °C) was organoleptically acceptable up to 8 h, when the bacterial load was more than 106 cfu/g. However, the prawn muscle stored at freezer temperatures (−10 to −15 °C) was found to be in acceptable condition even after 30 d of storage and the bacterial load was fluctuating in the range of 103 to 104 cfu/g.
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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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The effect of glazes of various tea extracts upon the storage stability and the quality of bonito fillet and its associated storage deterioration are examined. Fresh bonito fillets were glazed using either water or tea extracts, which had been allowed to ferment to various extents. Ice glazing enhanced the storage quality of the bonito fillet as compared to an untreated sample. Some of the tea-glazing treatments did provide some degree of protection, although some did not. The antioxidant activity of a particular species of tea as impacted upon bonito flesh related substantially to the extent of natural fermentation of the tea species used for glazing. Green tea and Pouchong tea afforded better protection than black tea for both lipid oxidation and protein oxidation within bonito flesh, therefore they maintained a better quality of preserved bonito fillet. The combination of a glazing treatment and the application of green or Pouchong tea extract at a 5% concentration was able to greatly increase the storage quality of the frozen bonito fillets.
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Effects of ferulic acid (FA) on polyphenoloxidase (PPO) and the quality changes of Pacific white shrimp (Litopenaeus vannamei) during iced storage for 10 days were investigated. Both FA and oxygenated FA (OFA) with different concentrations (0.1%, 0.5%, 1% and 2% (w/v)) showed PPO inhibitory activity in a dose dependent manner. FA was generally more effective in PPO inhibition than was OFA. Based on activity staining, white shrimp PPO with an apparent molecular weight of 210 kDa was inhibited by FA. When whole shrimps were treated with FA solution with concentrations of 1% or 2% and stored in ice for up to 10 days, the increase in psychrophilic and mesophilic bacterial count were retarded, in comparison with the control and those treated with 1.25% sodium metabisulphite (SMS). The coincidental lower rates of increase in pH and total volatile base content were obtained. Additionally, shrimps treated with 2% FA possessed the lowest peroxide value and thiobarbituric acid reactive substances (TBARS) value during the storage. After 10 days of storage, shrimps treated with 2% FA had the lower melanosis score and higher score for colour, flavour and overall likeness, compared with the control and SMS treated shrimps (P < 0.05).
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Effects of sodium bicarbonate with traces of citric acid in combination with sodium chloride on yield, freezing time, freezing rate, freezing loss and cutting force of white shrimp frozen by shelf, air-blast and cryogenic freezing with/without precooking were investigated. Shelf freezing was done at −40 °C ± 2 °C while air-blast freezing was carried out at −35 °C ± 2 °C, and cryogenic freezing was done at −35 °C, −40 °C and −60 °C. The freezing loss in the non-treated samples was 8.25, 4.6–5.84 and 1.92–3.48 g/100 g fresh shrimp for peeled samples frozen without precooking and increased to 21.85, 17.54–26.97, 17.92–20.31 g/100 g fresh shrimp in the precooked samples frozen by shelf, air-blast and cryogenic freezing, respectively. The treatment of sodium bicarbonate containing traces of citric acid at 4 g/100 ml with sodium chloride at 3 g/100 ml lead to the increase of yield thus reduced the freezing loss by about 6.83–10.28 and 6.41–12.4 g/100 g fresh shrimp for the frozen–thawed samples frozen as uncooked and cooked products, respectively. The toughening of shrimp was observed while sodium bicarbonate containing traces of citric acid treatment with sodium chloride could reduce the texture change occurred during the freezing.
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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.
Article
Solutions of green tea (Camellia sinensis) extract (GTE) in distilled water were evaluated as a glazing material for shrimp frozen by cryogenic freezing. Total of 2%, 3%, and/or 5% GTE solutions (2GTE, 3GTE, 5GTE) were used for glazing. Distilled water glazed (GDW) and nonglazed shrimp (NG) served as controls. The GTE was characterized by measuring color, pH, (o) Brix, total phenols, and % antiradical activity. Individual catechins were identified by HPLC. The freezing time, freezing rate, and energy removal rate for freezing shrimp by cryogenic freezing process were estimated. The frozen shrimp samples were stored in a freezer at -21 °C for 180 d. Samples were analyzed for pH, moisture content, glazing yield, thaw yield, color, cutting force, and thiobarbituric acid reactive substances (TBARS) after 1, 30, 90, and 180 d. The HPLC analysis of GTE revealed the presence of catechins and their isomers and the total polyphenol content was 148.10 ± 2.49 g/L. The freezing time (min) and energy removal rate (J/s) were 48.67 ± 2.3 and 836.67 ± 78.95, respectively. Glazed samples had higher moisture content compared to NG shrimp after 180 d storage. GTE was effective in controlling the lipid oxidation in shrimp. Glazing with GTE affected a* and b* color values, but had no significant effect on the L* values of shrimp.
Article
The decontamination of poultry carcasses is gaining increased interest in Europe, especially because poultry is implicated as a risk factor in human campylobacteriosis. Thus we appraised the antibacterial activity of interventions applied on poultry carcasses. Physical interventions included water-based treatments, irradiation, ultrasound, air chilling, or freezing. Especially hot water, steam, electrolyzed water (EW), and irradiation effectively reduced the bacterial load. Reductions obtained by hot water, steam, and EW mainly ranged from 0.9 to 2.1, 2.3 to 3.8, and 1.1 to 2.3 orders of magnitude, respectively. However, hot water or steam might exert an adverse impact on the carcass appearance. Chemical interventions primarily comprised organic acids, chlorine-based treatments, or phosphate-based treatments. Thereby, acetic and lactic acid, acidified sodium chlorite, and trisodium phosphate mainly yielded reductions in the range from 1.0 to 2.2 orders of magnitude. Besides, some combination treatments further enhanced the reductions. However, organic matter often reduces the antimicrobial activity of chemicals. Furthermore, biological interventions (e.g. bacteriophages) constitute promising alternatives, but further investigations are required. Although the mentioned interventions reduced the bacterial loads on poultry carcasses to some extent, decontamination treatments always must be considered part of an integral food safety system.
Article
The effect of modified atmosphere packaging (MAP) on the quality changes of Pacific white shrimp (Litopenaeus vannamei) treated with or without green tea extract (1g/L; GTE) in combination with or without ascorbic acid (0.05g/L; AA) during refrigerated storage of 10days was investigated. Shrimp without treatment stored under MAP had lowered psychrotrophic bacteria, enterobacteriaceae and H(2)S-producing bacteria count (P<0.05) but similar lactic acid bacteria count (P>0.05), in comparison with shrimp stored in air (control). The coincidental lowered rate of increase in pH, total volatile base (TVB) content and thiobarbituric acid reactive substances (TBARS) were obtained in shrimp stored under MAP (P<0.05). However, MAP slightly lowered melanosis formation and improved likeness score to some extent. When shrimp were treated with GTE and stored under MAP, the lower microbiological and chemical changes as well as the lowest melanosis formation were observed, compared to shrimp kept under MAP without treatment and the control (P<0.05). GTE treatment in combination with MAP could retard chemical changes and melanosis formation, regardless of AA incorporation (P>0.05). Nevertheless, GTE in combination with AA had higher inhibition on microbial growth and yielded the shrimp with higher likeness, compared with the other treatments (P<0.05). Therefore, shrimp treated with GTE in combination with AA prior to MAP had the lowest losses in quality during refrigerated storage.
Article
In this work the influence of different packaging strategies on the shelf life of ready to use peeled shrimps was investigated. First, the effectiveness of the coating (Coat) and the active coating loaded with different concentrations of thymol (Coat-500, Coat-1000, and Coat-1500) on the quality loss of the investigated food product packaged in air was addressed; afterwards, the thymol concentration that had shown the best performance was used in combination with MAP (5% O(2); 95% CO(2)). Microbial cell load of main spoilage microorganisms, pH and sensorial quality were monitored during the refrigerated storage. Results of the first step suggested that the sole coating did not affect the microbial growth. A slight antimicrobial effect was obtained when the coating was loaded with thymol and a concentration dependence was also observed. Moreover, the active coating was effective in minimizing the sensory quality loss of the investigated product, it was particularly true at the lowest thymol concentration. In the second step, the thymol concentration (1000 ppm) that showed the strike balance between microbial and sensorial quality was chosen in combination with MAP. As expected, MAP significantly affected the growth of the mesophilic bacteria. In particular, a cell load reduction of about 2 log cycle for the samples under MAP respect to that in air was obtained. Moreover, the MAP packaging inhibited the growth of the Pseudomonas spp. and hydrogen sulphide-producing bacteria. The MAP alone was not able to improve the shelf life of the uncoated samples. In fact, no significant difference between the control samples packaged in air and MAP was observed. Whilst, the use of coating under MAP condition prolonged the shelf life of about 6 days with respect to the same samples packaged in air. Moreover, when the MAP was used in combination with thymol, a further shelf life prolongation with respect to the samples packaged in air was observed. In particular, a shelf life of about 14 days for the active coating under MAP compared to the same samples in air (5 days) was obtained.
Article
Adequate glazing (6-10%) of fish fillets prior to frozen storage protects the final product from dehydration, oxidation and quality loss. Excessive glazing (>12%) on the other hand may significantly affect the economic value and end user satisfaction of frozen fish fillets. This paper describes the optimization, validation and application of a gravimetric procedure for the quantification of the ice-glaze content of frozen fish fillets (accredited under ISO 17025). This procedure has been utilized to determine the glazing percentage of multiple batches (n=50) of 11 different fish species sampled from 2005 until 2009. Average glazing percentages were 8.7+/-2.0% for the pooled samples (n=712), and ranged between 6.6+/-2.2% (salmon/cod) and 10.6+/-1.6% (plaice). The lower threshold value of 6% glazing for sufficient protection was violated in only one batch, whereas none of the batches exceeded the 12% excessive glazing threshold. The annual market place value of one %-point glazing is estimated at 1 million Euro in a low to moderate fish consumption market like Belgium. The large variability of glazing, combined with this technology's possible implications with respect to end-product-quality and economic value urges for technology improvement, monitoring and more controlled application of the glazing process in the frozen fish industry.
Article
This study investigated the efficacy of sanitized ice for the reduction of bacteria in the water collected from the ice that melted during storage of whole and filleted Tilapia fish. Also, bacterial reductions on the fish fillets were investigated. The sanitized ice was prepared by freezing solutions of PRO-SAN (an organic acid formulation) and neutral electrolyzed water (NEW). For the whole fish study, the survival of the natural microflora was determined from the water of the melted ice prepared with PRO-SAN and tap water. These water samples were collected during an 8 h storage period. For the fish fillet study, samples were inoculated with Escherichia coli K12, Listeria innocua, and Pseudomonas putida then stored on crushed sanitized ice. The efficacies of these were tested by enumerating each bacterial species on the fish fillet and in the water samples at 12 and 24 h intervals for 72 h, respectively. Results showed that each bacterial population was reduced during the test. However, a bacterial reduction of < 1 log CFU was obtained for the fillet samples. A maximum of approximately 2 log CFU and > 3 log CFU reductions were obtained in the waters sampled after the storage of whole fish and the fillets, respectively. These reductions were significantly (P < 0.05) higher in the water from sanitized ice when compared with the water from the unsanitized melted ice. These results showed that the organic acid formulation and NEW considerably reduced the bacterial numbers in the melted ice and thus reduced the potential for cross-contamination.
Article
Vibrio parahaemolyticus and Vibriovulnificus cause severe foodborne illness in humans; thus, to reduce outbreaks of disease, it is clearly important to reduce food contamination by these pathogens. Although electrolyzed oxidizing (EO) water has been reported to exhibit strong bactericidal activities against many pathogens, it has never been tested against V. vulnificus and V. parahaemolyticus. The purpose of this study was to evaluate the bactericidal activity of weakly acidic electrolyzed water (WAEW), a type of EO water, against V. vulnificus and V. parahaemolyticus. Cell suspensions and cell cultures of both pathogens were treated for 30s with sodium hypochlorite solution containing 35mg/L available chlorine concentration (ACC) or WAEW containing 35mg/L ACC. After an initial inoculum of 5.7logCFU/mL, the number of viable V. vulnificus cells was reduced by 2.2 logs after treatment for 60s with sodium hypochlorite solution containing 35mg/L ACC, while no cells survived treatment with WAEW for 30s. Similar results were obtained for V. parahaemolyticus. Under open storage conditions, WAEW maintained bactericidal activities against cell suspensions of both strains after 5weeks but disappeared against cell cultures of the two strains after 5weeks. Under closed storage conditions, however, WAEW maintained bactericidal activities against both cell suspensions and cell cultures of each strain after 5weeks. No cells were detected in the cell suspensions and cultures when the ACC of WAEW was more than 20mg/L and treatment time was greater than 15s. Bactericidal activity of WAEW against V. vulnificus cell culture was reduced when the ACC of WAEW was less than 15mg/L but was maintained in the V. vulnificus cell suspension when the ACC of WAEW was 0.5mg/L. Thus, the bactericidal activity of WAEW was primarily affected by ACC rather than treatment time. Similar results were obtained for V. parahaemolyticus, indicating that WAEW kills these microorganisms more quickly than a chemical product such as sodium hypochlorite (NaClO), even at equivalent ACCs.
Article
Prediction of shelf life based on growth of specific spoilage organisms (SSO) in model substrates was studied. The effect of CO2 on the growth kinetics for Photobacterium phosphoreum and Shewanella putrefaciens was quantified and modelled. Results showed that microbial spoilage of packed cod stored with various concentrations of CO2 was accurately predicted from the effect of CO2 on P. phosphoreum grown in model substrates. The short shelf life extensions previously reported for packed cod therefore can be explained by the high CO2 resistance of this Gram negative organism. S. putrefaciens was very sensitive to CO2 and growth rates could not be related to the shelf life of packed cod. Growth curves without lag phases were found for all concentrations of CO2 and for both the microorganisms studied. For the fitting of these growth curves the log-transformed Logistic models were selected after comparison with the 'modified Gompertz' models and with the model of Baranyi et al. (1993). The effect of CO2 on mu max was well described by a 2 parameter square root model. Validation of kinetic models by comparison of shelf life predictions with shelf life determined by sensory evaluations in product experiments was preferred for comparison of microbial growth rates determined in product and model system experiments. Kinetic modelling was found to be valuable for both evaluation and prediction of microbial fish spoilage and an iterative approach for development of kinetic shelf life models was suggested.
Article
Electrolyzed anodic NaCl solutions [EW+], prepared by the electrolysis of 0.1% NaCl, have been shown to instantly inactivate most pathogens that cause food-borne disease. Elimination of food-borne pathogens does not necessarily guarantee food safety because enterotoxins produced by pathogens may remain active. We have tested whether EW+ can inactivate Staphylococcal enterotoxin A (SEA), one of the major enterotoxins responsible for food poisoning. Fixed quantities of SEA were mixed with increasing molar ratios of EW+, and SEA was evaluated by reversed-phase passive latex agglutination (RPLA) test, immunoassay, native polyacrylamide gel electrophoresis (PAGE), and amino acid analysis after 30 min incubations. Exposure of 70 ng, or 2.6 pmol, of SEA in 25 microL of PBS to a 10-fold volume of EW+, or ca. 64.6 x 10(3)-fold molar excess of HOCl in EW+, caused a loss of immuno-reactivity between SEA and a specific anti-SEA antibody. Native PAGE indicated that EW+ caused fragmentation of SEA, and amino acid analysis indicated a loss in amino acid content, in particular Met, Tyr, Ile, Asn, and Asp. Staphylococcal enterotoxin-A excreted into culture broth was also inactivated by exposure to an excess molar ratio of EW+. Thus, EW+ may be a useful management tool to ensure food hygiene by food processing industries.
Article
We investigated the effects of frozen acidic electrolyzed water (AcEW) on lettuce during storage in a styrene-foam container. The lettuce was kept at 2 to 3 degrees C for 24 h. Populations of aerobic bacteria associated with lettuce packed in frozen AcEW were reduced by 1.5 log CFU/g after storage for 24 h. With frozen tap water, no microorganism populations tested in this study were reduced. A frozen mixture of AcEW and alkaline electrolyzed water (AlEW) also failed to reduce populations of microorganisms associated with lettuce. Although chlorine gas was produced by frozen AcEW, it was not produced by the AcEW-AlEW mixture. This result indicates that the main factor in the decontaminative effect of frozen AcEW was the production of chlorine gas. Accordingly, low-temperature storage and decontamination could be achieved simultaneously with frozen AcEW during distribution.