Read Books Online and Download eBooks, EPub, PDF, Mobi, Kindle, Text Full Free.
Depuration As A Method To Reduce Vibrio Vulnificus Populations In Live Crassostrea Virginica Oysters
Download Depuration As A Method To Reduce Vibrio Vulnificus Populations In Live Crassostrea Virginica Oysters full books in PDF, epub, and Kindle. Read online Depuration As A Method To Reduce Vibrio Vulnificus Populations In Live Crassostrea Virginica Oysters ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
Book Synopsis Depuration as a Method to Reduce Vibrio Vulnificus Populations in Live Crassostrea Virginica Oysters by : Oleksandr S. Tokarskyy
Download or read book Depuration as a Method to Reduce Vibrio Vulnificus Populations in Live Crassostrea Virginica Oysters written by Oleksandr S. Tokarskyy and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Vibrio vulnificus is a foodborne bacterial pathogen associated with raw oyster consumption. Shellfish depuration for 48 hours is a dynamic process where coliform bacteria are purged; however, this process is ineffective against V. vulnificus. The current study investigated the use of prolonged two-week depuration on V. vulnificus populations in Gulf Coast oysters. The study evaluated the impact of prolonged depuration on V. vulnificus fatty acid profile change and the ability to survive in simulated gastric fluid. Oyster depuration in seawater (10 or 22oC, 14 days) reduced V. vulnificus counts, but not to non-detectable level, indicating close ecological relationship between the pathogen and mollusk. Greatest V. vulnificus count reductions were seen in 12 ppt 10°C seawater (2.7 log10 CFU/g) and in 20 ppt 22°C seawater (2.8 logs). Mesophilic vibrios dominated the overall microflora of freshly harvested oysters, while refrigeration selected for psychrotrophic bacteria. Depuration at 22°C retained dominance of mesophilic vibrios, including pathogenic species. Although aerobic plate counts were lower in 22°C depurated oysters (5.0 logs vs 6.0 logs), depuration at 10°C had little to no advantage over 22°C in terms of vibrio population reduction. Use of prolonged depuration remains economically questionable since this method failed to completely eliminate V. vulnificus. Starved V. vulnificus behavior in artificial seawater showed that low temperature (4oC) and high seawater salinity (35 ppt) contributed to pathogen population reduction. Starved V. vulnificus did not adjust membrane fluidity to storage temperature within the investigated time frame. However, a significant fatty acid switch from C18:1w7c to C18:1w6c by double bond relocation was observed. The relocation was faster at ambient temperatures compared to refrigerated temperatures. The majority of V. vulnificus foodborne infections occur during warm summer months. Vibrio vulnificus ATCC 27562 was significantly less resistant (3.7 min D-value) to simulated gastric fluid (pH 4.0) after 7-day storage at 4oC compared to the control (7.8 min D-value). Therefore, greater gastric fluid sensitivity of the pathogen may occur in winter-harvested oysters and may partially explain the low number of winter outbreaks.
Book Synopsis Low-temperature Post-harvest Processing for Reducing Vibrio Parahaemolyticus and Vibrio Vulnificus in Raw Oysters by : Minjung Chae
Download or read book Low-temperature Post-harvest Processing for Reducing Vibrio Parahaemolyticus and Vibrio Vulnificus in Raw Oysters written by Minjung Chae and published by . This book was released on 2008 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: Oysters are filter-feeding bivalves, which filter water for nutrients and often accumulate contaminants and human pathogens such as Vibrio parahaemolyticus and Vibrio vulnificus naturally occurring in the marine environment. These naturally occurring pathogens have been frequently isolated from raw shellfish, particularly oyster, in the United States and are recognized as the leading causes of human gastroenteritis associated with seafood consumption. Human illness caused by consumption of raw oyster contaminated with V. parahaemolyticus and Vibrio vulnificus typically results in reduced sales of oysters and a consequent significant financial burden for the producers. The United States produces more than 27 million pounds of oysters each year with a large portion of them being produced from the coastal water of the Gulf of Mexico. It is estimated that 20 million Americans eat raw shellfish and consumption of raw oyster is responsible for about 95% of all deaths associated with seafood consumption in the U.S., making raw oysters one of the most hazardous seafoods. Several post-harvest processes, including low temperature pasteurization, freezing, high pressure processing and irradiation, have been reported capable of reducing Vibrio contamination in raw oysters. However, most of them require either a significant amount of initial investment or operation costs, and oysters are often killed during processing. Cost-effective post-harvest processing for reducing V. parahaemolyticus in raw oysters without significant adverse effects on the oysters remains to be developed. This study was conducted to determine impacts of low-temperature (15, 10 and 5°C) depuration and frozen storage on reducing V. parahaemolyticus and V. vulnificus in raw oysters. Depuration of the Gulf oyster (Crassostrea virginica) with electrolyzed oxidizing (EO) water (chlorine, 30 ppm; pH 2.82; oxidation-reduction potential, 1,131mV) containing 3% NaCl was found ineffective on reducing both V. parahaemolyticus and V. vulnificus in the oysters. Reductions of V. parahaemolyticus and V. vulnificus in oyster after 48 h of EO water depuration at 22°C were limited to 0.7 and 1.4 log MPN/g, respectively. Depuration with EO water at lower temperatures did not enhance reductions of Vibrio in the oysters. Greater reductions of V. parahaemolyticus (1.2 log MPN/g) and V. vulnificus (2.0 log MPN/g) were observed when the oysters were depurated with artificial seawater (ASW) at room temperature (22°C) for 48 h. Decreasing temperature of ASW to 15°C for depuration significantly increased the reductions of V. parahaemolyticus and V. vulnificus to 2.1 and 2.9 log MPN/g, respectively, after 48 h of process. However, depuration of oyster in ASW at 10 and 5°C were found less effective than at 15°C in reducing Vibrio in the Gulf oysters. An extended depuration with ASW at 15°C for 96 h was capable of achieving 2.6 and 3.3 log MPN/g of reductions of V. parahaemolyticus and V. vulnificus, respectively, in the Gulf oysters. Study of effects of frozen storage at -10, -23 and -30°C on reducing V. parahaemolyticus in raw half-shell Pacific oyster (Crassostrea gigas) found that the population of the bacterium decreased faster in oysters stored at -10 than at -23 or -30°C. Holding half-shell Pacific oyster at -10°C for three months or at -23°C for four months was capable of achieving a greater than 3-log (MPN/g) reduction of V. parahaemolyticus in the Pacific oyster.
Book Synopsis Diacetyl-assisted Depuration to Reduce Loads of Vibrio Vulnificus in the Eastern Oyster, Crassostrea Virginica by : Jennifer Michelle Birkenhauer
Download or read book Diacetyl-assisted Depuration to Reduce Loads of Vibrio Vulnificus in the Eastern Oyster, Crassostrea Virginica written by Jennifer Michelle Birkenhauer and published by . This book was released on 2001 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: Vibrio vulnificus is a highly virulent human pathogen that naturally occurs among the microflora of oysters. This organism has two portals of entry in humans, one of which is ingestion. Oysters containing V vulnificus consumed in a raw or undercooked state often serve as a vehicle of disease transmission for this organism. Previous studies conducted in our laboratory have examined various "Generally Recognized As Safe" (GRAS) compounds and have determined diacetyl, a component of butter, among the most effective for reducing loads of this pathogen in oysters. The purpose of this study was to further examine the role of diacetyl along with depuration in reducing loads of V vulnificus. When shellstock oysters were treated with varying concentrations of diacetyl we found that many of the oysters will cease pumping upon diacetyl addition. The data indicated that diacetyl is an ineffective treatment, however, any reduction may have been masked by sampling groups of oysters, some of which may not have taken up diacetyl. We then investigated the efficacy of diacetyl in lowering levels of V vulnificus in shucked oysters. Diacetyl was found to significantly reduce the load of V. vulnificus in both artificially infected shucked oysters, and in shucked oysters containing natural populations. Overall, it appears as if diacetyl is an ineffective treatment for shellstock oysters, while it has potential for use in reducing loads of V. vulnificus in shucked oysters.
Book Synopsis Evaluation of a Flow-through Depuration System to Eliminate the Human Pathogen Vibrio Vulnificus from the Eastern Oyster (Crassostrea Virginica) by : Matthew Robert Lewis
Download or read book Evaluation of a Flow-through Depuration System to Eliminate the Human Pathogen Vibrio Vulnificus from the Eastern Oyster (Crassostrea Virginica) written by Matthew Robert Lewis and published by . This book was released on 2010 with total page 65 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Reduction and Management of Vibrio Vulnificus in Gulf Coast Oyster (Crassostrea Virginica) by : Yu-Pin Chen
Download or read book Reduction and Management of Vibrio Vulnificus in Gulf Coast Oyster (Crassostrea Virginica) written by Yu-Pin Chen and published by . This book was released on 1996 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Evaluation of the Interaction Between the Eastern Oyster (Crassostrea Virginica) and Vibrio Vulnificus During Uptake and Depuration Using a Transposon Mutant of Vibrio Vulnificus by : Trudi Nan Groubert
Download or read book Evaluation of the Interaction Between the Eastern Oyster (Crassostrea Virginica) and Vibrio Vulnificus During Uptake and Depuration Using a Transposon Mutant of Vibrio Vulnificus written by Trudi Nan Groubert and published by . This book was released on 1992 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Two Post-harvest Treatments for the Reduction of Vibrio Vulnificus and Vibrio Parahaemolyticus in Eastern Oysters (Crassostrea Virginica) by : Kevin Patrick Melody
Download or read book Two Post-harvest Treatments for the Reduction of Vibrio Vulnificus and Vibrio Parahaemolyticus in Eastern Oysters (Crassostrea Virginica) written by Kevin Patrick Melody and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Refrigerated Seawater Depuration for Reducing Vibrio Parahaemolyticus Contamination in Raw Pacific Oysters (Crassostrea Gigas) by : Qianru Yang
Download or read book Refrigerated Seawater Depuration for Reducing Vibrio Parahaemolyticus Contamination in Raw Pacific Oysters (Crassostrea Gigas) written by Qianru Yang and published by . This book was released on 2009 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vibrio parahaemolyticus is a seafood-borne pathogen that can cause gastroenteritis in humans. This study investigated the effectiveness of refrigerated seawater (5°C) depuration on reducing V. parahaemolyticus in raw Pacific oysters (Crassostrea gigas). Raw Pacific oysters were inoculated with a mixed culture of five clinical strains of V. parahaemolyticus and depurated with cold seawater (5°C) in a pilot scale recirculating system. The refrigerated seawater depuration was more efficient in reducing V. parahaemolyticus contamination in oysters harvested in winter than in summer. Populations of V. parahaemolyticus in oysters harvested in winter were reduced by >1.2 log MPN/g after 24 h of depuration in refrigerated seawater. Reductions of V. parahaemolyticus in the oysters increased to about 2.3 log MPN/g after 48 h and reached 3.1 log after 96 h of the process. However, it required 144 h of depuration in the refrigerated seawater to achieve a 3-log (MPN/g) reduction of V. parahaemolyticus in oysters harvested in summer. The efficacies of refrigerated seawater depuration in reducing V. parahaemolyticus were determined at a rate of 0.0211-log/h in oysters harvested in the summer and 0.0362-log/h in oysters harvested in the winter. This is probably due to the differences between water temperatures of the oyster harvest site (7-9°C in winter, 16-17°C in summer) and the refrigerated seawater (5°C). Because of the increased temperature difference in the summer, it would require a longer time for oysters to adjust their biological activity to the new environment. Depuration of raw oysters in recirculated refrigerated seawater (5°C) for up to 144 h did not cause a noticeable fatality of oysters, but increased their ability to survive in subsequent cold storage. The process also reduced fecal coliform contamination in oysters from 103 MPN/g to less than 20 MPN/g. When oysters were stored in a refrigerator, 90% of oysters with or without depuration treatment survived after 7 days. However, the survival rate of oysters that had not been depurated in refrigerated seawater dropped sharply from 90 % to 44% after 9 days while 87% of depurated oysters remained alive after the same period of storage. No viable but nonculturable (VBNC) cells of V. parahaemolyticus were detected in the oysters depurated in refrigerated seawater for 144 h by reverse transcriptase polymerase chain reaction (RT-PCR) and multiplex PCR. Refrigerated seawater (5°C) depuration can be used as a simple and economical post-harvest treatment for reducing V. parahaemolyticus contamination in oysters. This process can easily be adopted by the shellfish industry for producing safe oysters for consumers and to reduce V. parahaemolyticus infection associated with raw oyster consumption.
Author :Food and Agriculture Organization of the United Nations Publisher :Food & Agriculture Org. ISBN 13 :9251320209 Total Pages :86 pages Book Rating :4.2/5 (513 download)
Book Synopsis Risk assessment tools for Vibrio parahaemolyticus and Vibrio vulnificus associated with seafood by : Food and Agriculture Organization of the United Nations
Download or read book Risk assessment tools for Vibrio parahaemolyticus and Vibrio vulnificus associated with seafood written by Food and Agriculture Organization of the United Nations and published by Food & Agriculture Org.. This book was released on 2020-02-10 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt: There has been an increase in reported outbreaks and cases of foodborne disease attributed to pathogenic Vibrio species. As a result, there have been several instances where the presence of pathogenic Vibrio spp. in seafood has led to a disruption in international trade. A number of Vibrio spp. are increasingly being recognized as potential human pathogens. The food safety concerns associated with these microorganisms have led to the need for microbiological risk assessment for their control. This report provides the review of risk assessment of existing tools for V. parahaemolyticus and V. vulnificus in oysters and different bivalve molluscan species, the available information on testing methodology and recommend microbiological methods to monitor the levels of pathogenic Vibrio spp. in seafood and/or water. Such tools are envisioned to support countries in their efforts to use risk-based approaches in the selection of control measures appropriate for their seafood species, primary production and post-harvest practices. This volume and others in this Microbiological Risk Assessment Series contain information that is useful to both risk assessors and risk managers, the Codex Alimentarius Commission, governments and regulatory authorities, food producers and processers and other institutions and individuals with an interest in Vibrio spp. and its control.
Book Synopsis Application of Antimicrobial Substance in Depuration for Decreasing Vibrio Parahaemolyticus Contamination in the Pacific Oysters (Crassostrea Gigas) by : Xiaoye Shen
Download or read book Application of Antimicrobial Substance in Depuration for Decreasing Vibrio Parahaemolyticus Contamination in the Pacific Oysters (Crassostrea Gigas) written by Xiaoye Shen and published by . This book was released on 2016 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vibrio parahaemolyticus is the leading cause of foodborne illnesses associated with seafood consumption. Consuming raw or undercooked seafood contaminated with V. parahaemolyticus can result in development of acute gastroenteritis with symptoms of nausea, vomiting, abdominal cramping and watery diarrhea within 24 hours of infection. Illness is usually self-limited and lasts for about 3 days. The United States Centers for Disease Control and Prevention estimated that 45,000 cases of V. parahaemolyticus occur annually in the U.S. Depuration is a process which holds shellfish in clean seawater to allow them to purge sand and bacteria. Recently, we developed a refrigerated seawater (7 to 15 °C) depuration capable of decreasing V. parahaemolyticus populations in oysters by >3.0 log MPN/g after 5 days of the process with no adverse effect on oysters. However, the process needs to be shorted to allow application by the shellfish industry. This study investigated the bactericidal activity of natural antimicrobial substances, including rosemary, marjoram, clove, and grape seed extract, against five clinical V. parahaemolyticus strains (10290, 10292, 10293, BE 98-2029, O27-1c1) for their potential applications in depuration to increase its efficacy in reducing V. parahaemolyticus populations in contaminated oysters. Marjoram and rosemary contain low levels of phenolic compounds and had very little antimicrobial activity against V. parahaemolyticus. However, clove and grape seed extract exhibited strong bactericidal effects against clinical strains of V. parahaemolyticus. Populations of V. parahaemolyticus in tryptic soy broth supplemented with 1.5% NaCl (TSB-salt) containing 1.5% clove extract decreased rapidly by >3.88 - >4.81 log CFU/ml within 1 h of incubation at 37 °C. Similarly, populations of V. parahaemolyticus in TSB-salt containing 1% grape seed extract all declined to non-detectable (>4.69-log reductions) after 2 h. Further studies confirmed that both 1.5% of clove extract and 1.0% grade seed extract in TSB-salt reduced a mixed culture of 5 clinical V. parahaemolyticus strains from 5.42 log CFU/ml to non-detectable (10 CFU/ml) in 1 h at 37 °C. Both clove and grape seed extract exhibited strong antimicrobial activity against clinical strains of V. parahaemolyticus and might be utilized as natural antimicrobial agents to reduce V. parahaemolyticus contamination in seafood. Studies of application of grape seed extract (GSE) in oyster depuration revealed that addition of GSE in artificial seawater (ASW) for depuration increased the efficacy of depuration for reducing V. parahaemolyticus populations in the Pacific oysters (Crassostrea gigas). The populations of V. parahaemolyticus in laboratory inoculated oysters decreased by 3.12 log MPN/g after 3 days of depuration in ASW at 12.5 °C. A greater reduction (3.61 log MPN/g) of V. parahaemolyticus populations in oysters was observed after 3 days of depuration at 12.5 °C with ASW containing 1.0% GSE containing 1.8 mg/ml total phenolic contents as gallic acid equivalents. Increasing the concentration of GSE in ASW from 1.0 to 1.5% greatly enhanced the efficacy of the depuration in decontaminating V. parahaemolyticus in oysters. Populations of V. parahaemolyticus in oysters decreased by 3.77 and 4.18 log MPN/g after one and two days of depuration in ASW containing 1.5% GSE (3.1 mg/ml total phenolic contents as gallic acid equivalents), respectively. However, it required 5 days of depuration in ASW at 12.5 °C to decrease V. parahaemolyticus populations in oysters by 3.71 log MPN/g. Addition of GSE in ASW greatly enhanced depuration process for decontaminating V. parahaemolyticus in oysters. Depuration at 12.5 °C with ASW containing 1.5% GSE was capable of achieving 3.52 log MPN/g reduction of V. parahaemolyticus in Pacific oysters in two days. Further studies are needed to validate the efficacy of this depuration process for decontaminating naturally accumulated V. parahaemolyticus in Pacific oysters.
Book Synopsis Risk assessment tools for Vibrio parahaemolyticus and Vibrio vulnificus associated with seafoods by : World Health Organization
Download or read book Risk assessment tools for Vibrio parahaemolyticus and Vibrio vulnificus associated with seafoods written by World Health Organization and published by World Health Organization. This book was released on 2020-02-20 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Survival of Vibrio Vulnificus and Escherichia Coli in Artificially and Naturally Infected Oyster (Crassostrea Virginica) Tissues During Storage in Spray- and Immersion-type Live Holding Systems by : Jhung-Won Colby
Download or read book Survival of Vibrio Vulnificus and Escherichia Coli in Artificially and Naturally Infected Oyster (Crassostrea Virginica) Tissues During Storage in Spray- and Immersion-type Live Holding Systems written by Jhung-Won Colby and published by . This book was released on 1992 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Electrolyzed Oxidizing Water Treatment for Reducing Vibrio Contamination in Oysters by : Tingting Ren
Download or read book Electrolyzed Oxidizing Water Treatment for Reducing Vibrio Contamination in Oysters written by Tingting Ren and published by . This book was released on 2005 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: Oysters can be easily contaminated with spoilage and pathogenic bacteria through contaminated waster. The United States produces more than 27 million pounds of oysters each year and most of them are sold and consumed raw without further processing. Growth of naturally contaminating bacteria in oysters during storage results in loss of quality and product value. Contamination of pathogenic bacteria such as Vibrio parahaemolyticus and Vibrio vulnificus in oysters is also a safety concern of the industry and consumers. The traditional depuration process for reducing bacterial contamination in oysters using clean seawater has been reported to be ineffective in reducing Vibrio contamination in oysters. This study investigated effects of electrolyzed oxidizing (EO) water treatment on reducing both V. parahaemolyticus and V. vulnificus contamination in oysters. Freshly harvested Pacific oysters were inoculated with 5-strain cocktail of V. parahaemolyticus or V. vulnificus at levels of 104 and 106 MPN/g. Inoculated oysters were held in EO water (chlorine: 30 ppm, pH: 2.82, ORP: 1131 mV) containing 1% NaCl at room temperature. Reductions of V. parahaemolyticus and V. vulnificus in oysters during the treatment were determined at 0, 2, 4, 6, and 8 h. EO water containing 30 ppm of chlorine was found to exhibit strong bactericidal effects against pure cultures of V. parahaemolyticus and V. vulnificus (>6.6-log reductions in 15s). Holding oysters inoculated with V. parahaemolyticus or V. vulnificus in EO water (30 pin chlorine) containing 1% NaCl for 4-6 h resulted in significant reductions of V. parahaemolyticus and V. vulnificus by 1.13 and 1.05 log MPN/g, respectively. However, extended exposure (>12 h) of oysters in EO water containing high levels of chlorine (>30 ppm) was found to be detrimental to oysters. EO water could be used as a post-harvest treatment to reduce Vibrio contamination in oysters. However, treatment should be limited to 4-6 h to avoid death of oysters. Further studies are needed to determine effects of EO water treatments on sensory characteristics of treated oysters.
Book Synopsis Rapid Cooling of Eastern Oysters (Crassostrea Virginica) Using an On-board Icing Unit to Slow the Growth of Vibrio Vulnificus and Vibrio Parahaemolyticus by : Melody Amber Thomas
Download or read book Rapid Cooling of Eastern Oysters (Crassostrea Virginica) Using an On-board Icing Unit to Slow the Growth of Vibrio Vulnificus and Vibrio Parahaemolyticus written by Melody Amber Thomas and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Factors Affecting the Efficacy of Depuration for Decreasing Vibrio Parahaemolyticus Contamination in Pacific Oysters (Crassostrea Gigas) by : Yishu Hou
Download or read book Factors Affecting the Efficacy of Depuration for Decreasing Vibrio Parahaemolyticus Contamination in Pacific Oysters (Crassostrea Gigas) written by Yishu Hou and published by . This book was released on 2015 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vibrio parahaemolyticus is a foodborne pathogen recognized as the leading cause of acute gastroenteritis associated with consumption of raw and undercooked seafood, particularly raw oysters, with major symptoms of nausea, vomiting, abdominal cramps and diarrhea. It is estimated that 45,000 cases of V. parahaemolyticus infection occur each year in the United States. In order to reduce the high risks of V. parahaemolyticus infection associated with raw oyster consumption, post-harvest processes capable of decreasing V. parahaemolyticus levels by >3.52 log MPN/g are recommended by the U.S. Food and Drug Administration for oyster processing upon harvest. Depuration is a process of holding shellfish in clean seawater allowing shellfish to purge contaminants and may be applied by the shellfish industry as a post-harvest process to reduce contamination of V. parahaemolyticus in oysters. Currently, depuration at controlled temperatures between 7 and 15°C for 5 days has been developed to achieve >3.0 but 3.52 log MPN/g reductions of V. parahaemolyticus in oysters. The aim of this study was to investigate the factors, including water pH value, water temperature and oyster to water ratio, affecting the efficacy of depuration in decreasing V. parahaemolyticus in oysters and to improve the efficacy of depuration process to achieve 3.52 log MPN/g reductions of V. parahaemolyticus in oysters for application as a post-harvest treatment of oysters by the shellfish industry to produce safe oysters for raw consumption. Studies of growth of V. parahaemolyticus in trypticase soy broth with 2% salt (TSB-Salt) medium of various pH values (5.5, 7.3 and 9.0) found that growth of five clinical V. parahaemolyticus strains were retarded in TSB-Salt at pH 5.5 compared with at pH 7.3 or 9.0. Investigation of oyster gaping in artificial seawater (ASW) of different pH values ranging from 4.0 to 10.5 unveiled that oysters survived well in ASW of pH between 5.0 and 9.5 at room temperature. Based on these findings, oyster depuration was conducted in a lab-scale depuration system with pH value of ASW being controlled at 5.5 or 7.0 at 12.5°C or 20°C for 5 days with an initial V. parahaemolyticus level in oysters of 104−5 MPN/g. Depuration with ASW (pH 8.3) without control of pH value was used as a control. Depuration in ASW of pH 5.5, 7.0 and 8.3 at 20°C for 5 days resulted in 0.7-2.0, 1.7-2.0 and 2.8 log MPN/g reductions of V. parahaemolyticus, respectively. Greater reductions (1.6-2.1 log MPN/g at pH 5.5, 2.9-3.0 log MPN/g at pH 7.0 and 3.5 log MPN/g at pH 8.3) of V. parahaemolyticus in oysters were observed after depuration with ASW at 12.5°C for 5 days. Decreasing pH value of ASW for depuration resulted in decreased efficacy of the process in reducing V. parahaemolyticus contamination in oysters. Study of effects of different oyster to water ratios (number of oyster : volume of water) of 1:1, 1:1.5, 1:2, and 1:2.5 revealed that depuration with oyster to water ratio of 1:2 could achieve >3.52 log MPN/g reductions after four days. This study improved the efficacy of depuration with ASW at 12.5°C to deliver >3.52 log MPN/g reductions of V. parahaemolyticus in the Pacific oysters. This controlled depuration may be applied as a post-harvest process to produce safe oysters for raw consumption. Future studies are needed to validate the efficacy of this controlled depuration for commercial application by the shellfish industry.
Book Synopsis The Effect of Temperature on Depuration of the Pathogenic Vibrio Anguillarum in the Eastern Oyster (Crassostrea Virginica) by : Ziwen Ye
Download or read book The Effect of Temperature on Depuration of the Pathogenic Vibrio Anguillarum in the Eastern Oyster (Crassostrea Virginica) written by Ziwen Ye and published by . This book was released on 2016 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Survival of Vibro Vulnificus and Other Vibrios in Raw Oysters (Crassostrea Virginica) During Processing in Virginia and Cold Storage by : Vicki C. Ostrander
Download or read book Survival of Vibro Vulnificus and Other Vibrios in Raw Oysters (Crassostrea Virginica) During Processing in Virginia and Cold Storage written by Vicki C. Ostrander and published by . This book was released on 1996 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt:
