Reductions of Vibrio parahaemolyticus in Pacific oysters (Crassostrea gigas) by depuration at various temperatures

2012 ◽  
Vol 31 (1) ◽  
pp. 51-56 ◽  
Author(s):  
Sureerat Phuvasate ◽  
Ming-Hui Chen ◽  
Yi-Cheng Su
Keyword(s):  
Crassostrea Gigas ◽  
Vibrio Parahaemolyticus ◽  
Pacific Oysters

Effects of Flash Freezing, Followed by Frozen Storage, on Reducing Vibrio parahaemolyticus in Pacific Raw Oysters (Crassostrea gigas)

2009 ◽  
Vol 72 (1) ◽  
pp. 174-177 ◽  
Author(s):  
CHENGCHU LIU ◽  
JIANZHANG LU ◽  
YI-CHENG SU
Keyword(s):  
Crassostrea Gigas ◽  
Vibrio Parahaemolyticus ◽  
Vibrio Vulnificus ◽  
Frozen Storage ◽  
Most Probable Number ◽  
Freezing Process ◽  
Probable Number ◽  
Pacific Oysters ◽  
Subsequent Storage ◽  
Shellfish Sanitation

This study investigated the effects of flash freezing, followed by frozen storage, on reducing Vibrio parahaemolyticus in Pacific raw oysters. Raw Pacific oysters were inoculated with a five-strain cocktail of V. parahaemolyticus at a total level of approximately 3.5 × 105 most probable number (MPN) per gram. Inoculated oysters were subjected to an ultralow flash-freezing process (−95.5°C for 12 min) and stored at −10, −20, and −30°C for 6 months. Populations of V. parahaemolyticus in the oysters declined slightly by 0.22 log MPN/g after the freezing process. Subsequent storage of frozen oysters at −10, −20, and −30°C resulted in considerable reductions of V. parahaemolyticus in the oysters. Storing oysters at −10°C was more effective in inactivating V. parahaemolyticus than was storage at −20 or −30°C. Populations of V. parahaemolyticus in the oysters declined by 2.45, 1.71, and 1.45 log MPN/g after 1 month of storage at −10, −20, and −30°C, respectively, and continued to decline during the storage. The levels of V. parahaemolyticus in oysters were reduced by 4.55, 4.13, and 2.53 log MPN/g after 6 months of storage at −10, −20, and −30°C, respectively. Three process validations, each separated by 1 week and conducted according to the National Shellfish Sanitation Program's postharvest processing validation–verification interim guidance for Vibrio vulnificus and Vibrio parahaemolyticus, confirmed that a process of flash freezing, followed by storage at −21 ± 2°C for 5 months, was capable of achieving greater than 3.52-log (MPN/g) reductions of V. parahaemolyticus in half-shell Pacific oysters.

Refrigerated Seawater Depuration for Reducing Vibrio parahaemolyticus Contamination in Pacific Oyster (Crassostrea gigas)

2010 ◽  
Vol 73 (6) ◽  
pp. 1111-1115 ◽  
Author(s):  
YI-CHENG SU ◽  
QIANRU YANG ◽  
CLAUDIA HÄSE
Keyword(s):  
Crassostrea Gigas ◽  
Vibrio Parahaemolyticus ◽  
Pacific Oyster ◽  
Most Probable Number ◽  
Probable Number ◽  
Log Reduction ◽  
Pacific Oysters ◽  
The Pacific ◽  
Postharvest Treatment ◽  
Depuration Process

The efficacy of refrigerated-seawater depuration for reducing Vibrio parahaemolyticus levels in Pacific oyster (Crassostrea gigas) was investigated. Raw Pacific oysters were inoculated with a mixed culture of five clinical strains of V. parahaemolyticus (105 to 106 most probable number [MPN] per g) and depurated with refrigerated seawater (5°C) in a laboratory-scale recirculation system equipped with a 15-W gamma UV sterilizer. Depuration with refrigerated seawater for 96 h reduced V. parahaemolyticus populations by >3.0 log MPN/g in oysters harvested in the winter. However, 144 h of depuration at 5°C was required to achieve a 3-log reduction in oysters harvested in the summer. Depuration with refrigerated seawater at 5°C for up to 144 h caused no significant fatality in the Pacific oyster and could be applied as a postharvest treatment to reduce V. parahaemolyticus contamination in Pacific oysters. Further studies are needed to validate the efficacy of the depuration process for reducing naturally accumulated V. parahaemolyticus in oysters.

Distribution of Vibrio parahaemolyticus ATCC17802 in tissues of adult Pacific oysters (Crassostrea gigas) under starvation conditions

Aquaculture ◽  
2020 ◽  
Vol 521 ◽  
pp. 735051
Author(s):  
Shuang Wang ◽  
Qing Kong ◽  
Petcharat Namwong ◽  
Peng Wang ◽  
Haijin Mou ◽  
...  
Keyword(s):  
Crassostrea Gigas ◽  
Vibrio Parahaemolyticus ◽  
Pacific Oysters ◽  
Starvation Conditions

scholarly journals Predictive Models for the Effect of Storage Temperature on Vibrio parahaemolyticus Viability and Counts of Total Viable Bacteria in Pacific Oysters (Crassostrea gigas)

2011 ◽  
Vol 77 (24) ◽  
pp. 8687-8695 ◽  
Author(s):  
Judith Fernandez-Piquer ◽  
John P. Bowman ◽  
Tom Ross ◽  
Mark L. Tamplin
Keyword(s):  
Predictive Models ◽  
Crassostrea Gigas ◽  
Vibrio Parahaemolyticus ◽  
Natural Populations ◽  
Parameter Estimates ◽  
Square Root ◽  
Probable Number ◽  
Direct Plating ◽  
Content Type ◽  
Pacific Oysters

ABSTRACTVibrio parahaemolyticusis an indigenous bacterium of marine environments. It accumulates in oysters and may reach levels that cause human illness when postharvest temperatures are not properly controlled and oysters are consumed raw or undercooked. Predictive models were produced by injecting Pacific oysters (Crassostrea gigas) with a cocktail ofV. parahaemolyticusstrains, measuring viability rates at storage temperatures from 3.6 to 30.4°C, and fitting the data to a model to obtain parameter estimates. The models were evaluated with Pacific and Sydney Rock oysters (Saccostrea glomerata) containing natural populations ofV. parahaemolyticus. V. parahaemolyticusviability was measured by direct plating samples on thiosulfate-citrate-bile salts-sucrose (TCBS) agar for injected oysters and by most probable number (MPN)-PCR for oysters containing natural populations. In parallel, total viable bacterial counts (TVC) were measured by direct plating on marine agar. Growth/inactivation rates forV. parahaemolyticuswere −0.006, −0.004, −0.005, −0.003, 0.030, 0.075, 0.095, and 0.282 log10CFU/h at 3.6, 6.2, 9.6, 12.6, 18.4, 20.0, 25.7, and 30.4°C, respectively. The growth rates for TVC were 0.015, 0.023, 0.016, 0.048, 0.055, 0.071, 0.133, and 0.135 log10CFU/h at 3.6, 6.2, 9.3, 14.9, 18.4, 20.0, 25.7, and 30.4°C, respectively. Square root and Arrhenius-type secondary models were generated forV. parahaemolyticusgrowth and inactivation kinetic data, respectively. A square root model was produced for TVC growth. Evaluation studies showed that predictive growth forV. parahaemolyticusand TVC were “fail safe.” The models can assist oyster companies and regulators in implementing management strategies to minimizeV. parahaemolyticusrisk and enhancing product quality in supply chains.

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