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.

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.

scholarly journals Distribution, Condition and Gonad Maturity of the Invasive Pacific Oysters (Crassostrea Gigas, Thunberg 1793) in Cimanuk Delta, Indramayu, West Java, Indonesia

Omni-Akuatika ◽  
2017 ◽  
Vol 13 (2) ◽  
Author(s):  
Selia Hermawati ◽  
Sulistiono Sulistiono ◽  
Agustinus M Samosir
Keyword(s):  
Distribution Pattern ◽  
Crassostrea Gigas ◽  
Brackish Water ◽  
Pacific Oyster ◽  
Condition Factor ◽  
Maturity Stage ◽  
West Java ◽  
Gonad Maturity ◽  
Pacific Oysters ◽  
The Pacific

Pacific oyster (Crassostrea gigas) is an invasive species which is able to adapt a wide range of environmental conditions. The study was conducted from August to October 2014. Objective of this study was to asses the distribution pattern, condition and gonad maturity length (Lm 50%) of the Pacific oysters in mangrove ecosystem of Cimanuk Delta, Indramayu, West Java, Indonesia.  This study was conducted in two adjacent areas:  Pabean Ilir and Pagirikan subdeltas. The oysters were collected from the estuary, brackish water ponds and the coastal flat, and  observed for their abundance, total length (mm) and weight (g). Morphological and histological methods were used to estimate the gonad maturity stage. Analysis were carried out to estimate distribution pattern and condition factor. According to the study, the Pacific oyster distribution pattern was clumped. The condition factor of the oyster was higher in the brackish water pond and estuary than in the coastal flat.  The Pacific oyster was found in gonad maturity stage (GMS) I – IV. The oyster was hermaprodit protandry and had length maturity (Lm 50%) of 47,46-48,43 mm (male) and 75,27-75,50  mm (female). 

Spatial Distribution of Pacific Oyster (Crassostrea gigas) Population Related Environment Factor in Coastal Water of Pabean Ilir, Indramayu

2020 ◽  
Vol 4 (1) ◽  
pp. 38-47
Author(s):  
Risma Qurani ◽  
Fredinan Yulianda ◽  
Agustinus Mangaratua Samosir
Keyword(s):  
Spatial Distribution ◽  
Coastal Water ◽  
Crassostrea Gigas ◽  
Pacific Oyster ◽  
Oyster Population ◽  
Pacific Oysters ◽  
The Pacific ◽  
Arc Gis ◽  
Environment Factor ◽  
Spatial Condition

Pacific oysters (Crassostrea gigas, Thunberg, 1793) is a benthic organisme that tend to live and settle in the bottom. One of the pacific oyster habitat is Coastal Water of Pabean Ilir, Indramayu. The purpose of this study was to map spatial condition of the population related habitat of the oyster (Crassostrea gigas). The mapping were done with laptop, using Arc GIS. There were 15 points of sampling. The oyster population in Pabean Ilir can be categorized into three categories: low, medium, and high density. Based on the similarity of environmental characteristics the habitat were divided into four groups. Condition Coastal Water of Pabean Ilir such as temperature, salinity, pH, BOD, TSS, TDS, COD, and composition of substrate indicated Coastal Water of Pabean Ilir have compatibility optimum sufficient habitat to support the growth of pacific oyster

Limitations of the A-IM Method for Fecal Coliform Enumeration in the Pacific Oyster (Crassostrea gigas)

1987 ◽  
Vol 70 (3) ◽  
pp. 535-537
Author(s):  
Charles A Kaysner ◽  
Stephen D Weagant
Keyword(s):  
Escherichia Coli ◽  
Positive Reaction ◽  
Crassostrea Gigas ◽  
Water Samples ◽  
Fecal Coliform ◽  
Pacific Oyster ◽  
Food Products ◽  
Fecal Coliforms ◽  
Pacific Oysters ◽  
The Pacific

Abstract Use of the A-IM method, which was originally devised for testing water samples, has recently been extended for enumeration of fecal coliforms and Escherichia coli in shellfish and other food products. Results of our study indicate that while this method is reliable for analysis of growing waters, the use of the A-IM method for testing Pacific oysters may be less reliable because bacteria not belonging to the coliform group but which are sometimes present in these animals also give a positive reaction.

Depuration of Oysters (Crassostrea gigas) Contaminated with Vibrio parahaemolyticus and Vibrio vulnificus with UV Light and Chlorinated Seawater

2012 ◽  
Vol 75 (8) ◽  
pp. 1501-1506 ◽  
Author(s):  
ROBERTA JULIANO RAMOS ◽  
MARÍLIA MIOTTO ◽  
FRANCISCO JOSÉ LAGREZE SQUELLA ◽  
ANDRÉIA CIROLINI ◽  
JAIME FERNANDO FERREIRA ◽  
...  
Keyword(s):  
Vibrio Parahaemolyticus ◽  
Vibrio Vulnificus ◽  
Uv Light ◽  
Control Treatment ◽  
Most Probable Number ◽  
Brazilian Coast ◽  
Uv Treatment ◽  
Probable Number ◽  
Postharvest Treatment ◽  
Small Producers

The efficacy of depuration using UV light and chlorinated seawater for decontaminating Vibrio parahaemolyticus and Vibrio vulnificus from oysters was investigated. Oysters were contaminated with a five-strain cocktail of V. parahaemolyticus or V. vulnificus to levels of 104 to 105 CFU ml−1 for bioaccumulation. The depuration was conducted in a closed system in which 350 liters of seawater was recirculated at a rate of 7 liters/min for 48 h at room temperature. Counts of V. parahaemolyticus or V. vulnificus were determined at 0, 6, 18, 24, and 48 h. Three treatments were conducted: T1, control treatment; T2, UV treatment; and T3, UV plus chlorine treatment. After 48 h of depuration of V. parahaemolyticus, T3 reduced the count by 3.1 log most probable number (MPN) g−1 and T2 reduced the count by 2.4 log MPN g−1, while T1 reduced the count by only 2.0 log MPN g−1. After 48 h of depuration of V. vulnificus, T2 and T3 were efficient, reducing the counts by 2.5 and 2.4 log MPN g−1, respectively, while T1 reduced the count by only 1.4 log MPN g−1. The UV light plus chlorine treatment was more efficient for controlling V. parahaemolyticus in oysters. Both UV light and UV light plus chlorine were efficient for V. vulnificus. The present study is the first report showing the efficacy of depuration systems for decontaminating V. parahaemolyticus and V. vulnificus in oysters cultivated on the Brazilian coast. This study provides information on processes that can contribute to controlling and preventing such microorganisms in oysters and could be used for effective postharvest treatment by restaurants and small producers of oysters on the coast of Brazil.

Detection of Escherichia albertii in retail oysters

2021 ◽  
Author(s):  
Sakura Arai ◽  
Satoko Yamaya ◽  
Kayoko Ohtsuka ◽  
Noriko Konishi ◽  
Hiromi Obata ◽  
...  
Keyword(s):  
Nested Pcr ◽  
Pacific Oyster ◽  
Genetic Characterization ◽  
Foodborne Pathogen ◽  
Most Probable Number ◽  
Macconkey Agar ◽  
Pcr Assay ◽  
Probable Number ◽  
Pacific Oysters ◽  
Rock Oyster

Escherichia albertii  is an emerging foodborne pathogen. Owing to its distribution in river water,  it is important to determine the presence of  E. albertii  in aquaculture-related foods. In this study, we investigated the distribution of  E. albertii  in retail oyster samples.  A total of  427 raw oyster samples (385 Pacific oysters, and 42 Japanese rock oysters) were enriched in  modified Escherichia coli  broth (mEC) or mEC supplemented with novobiocin (NmEC) at 42 °C. The cultures were used for  E. albertii -specific nested PCR assay, as well as for  E. albertii  isolation using  deoxycholate hydrogen sulfide lactose agar  (DHL), DHL supplemented with rhamnose and xylose (RX-DHL), and MacConkey agar supplemented with rhamnose and xylose (RX-MAC). The population of  E. albertii  in nested PCR-positive samples was  determined using the  most probable number  (MPN) method.  E. albertii  isolates were subjected to biochemical and genetic characterization.  E. albertii   was detected in 5 of 315 (1.6%) Pacific oyster samples  (one piece each), 2 of 70 (2.9 %)  Pacific oyster samples  (25 g each), and 2 of 42 (4.8 %) Japanese rock oyster samples  procured from four geographically distant regions. A total of 64  E. albertii  strains were isolated from eight of the nine nested PCR assay-positive oyster samples, and  the MPN value was under the detection limit (< 3 MPN/10 g).  A specific season or month for detecting  E. albertii  was not observed in this study, suggesting that the pathogen is present in seawater.   All the  E. albertii  isolates, except one, were positive for the virulence factor  eae,  indicating that these isolates have  the potential to infect humans.

Effects of Electrolyzed Oxidizing Water Treatment on Reducing Vibrio parahaemolyticus and Vibrio vulnificus in Raw Oysters

2006 ◽  
Vol 69 (8) ◽  
pp. 1829-1834 ◽  
Author(s):  
TINGTING REN ◽  
YI-CHENG SU
Keyword(s):  
Water Treatment ◽  
Vibrio Parahaemolyticus ◽  
Vibrio Vulnificus ◽  
Safety Concern ◽  
Most Probable Number ◽  
Probable Number ◽  
Pacific Oysters ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Pure Cultures

Contamination of Vibrio parahaemolyticus and Vibrio vulnificus in oysters is a food safety concern. This study investigated effects of electrolyzed oxidizing (EO) water treatment on reducing V. parahaemolyticus and V. vulnificus in laboratory-contaminated oysters. EO water exhibited strong antibacterial activity against V. parahaemolyticus and V. vulnificus in pure cultures. Populations of V. parahaemolyticus (8.74 × 107 CFU/ml) and V. vulnificus (8.69 × 107 CFU/ml) decreased quickly in EO water containing 0.5% NaCl to nondetectable levels (>6.6 log reductions) within 15 s. Freshly harvested Pacific oysters were inoculated with a five-strain cocktail of V. parahaemolyticus or V. vulnificus at levels of 104 and 106 most probable number (MPN)/g and treated with EO water (chlorine, 30 ppm; pH 2.82; oxidation-reduction potential, 1131 mV) containing 1% NaCl at room temperature. Reductions of V. parahaemolyticus and V. vulnificus in oysters were determined at 0 (before treatment), 2, 4, 6, and8hof treatment. Holding oysters inoculated with V. parahaemolyticus or V. vulnificus in the EO water containing 1% NaCl for 4 to 6 h resulted in significant (P < 0.05) reductions of V. parahaemolyticus and V. vulnificus by 1.13 and 1.05 log MPN/g, respectively. 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 postharvest treatment to reduce Vibrio contamination in oysters. However, treatment should be limited to 4 to6hto avoid death of oysters. Further studies are needed to determine effects of EO water treatment on sensory characteristics of oysters.

scholarly journals Ostreid Herpesvirus 1 Infection among Pacific Oyster (Crassostrea gigas) Spat: Relevance of Water Temperature to Virus Replication and Circulation Prior to the Onset of Mortality

2014 ◽  
Vol 80 (17) ◽  
pp. 5419-5426 ◽  
Author(s):  
Tristan Renault ◽  
Anne Lise Bouquet ◽  
Julien-Thomas Maurice ◽  
Coralie Lupo ◽  
Philippe Blachier
Keyword(s):  
Water Temperature ◽  
Crassostrea Gigas ◽  
Pacific Oyster ◽  
Mortality Rates ◽  
Mass Mortality ◽  
Content Type ◽  
Pacific Oysters ◽  
The Pacific ◽  
Herpesvirus 1 ◽  
Ostreid Herpesvirus 1

ABSTRACTA number of bivalve species worldwide, including the Pacific oyster,Crassostrea gigas, have been affected by mass mortality events associated with herpesviruses, resulting in significant losses. A particular herpesvirus was purified from naturally infected larval Pacific oysters, and its genome was completely sequenced. This virus has been classified asOstreid herpesvirus 1(OsHV-1) within the familyMalacoherpesviridae. Since 2008, mass mortality outbreaks amongC. gigasin Europe have been related to the detection of a variant of OsHV-1 called μVar. Additional data are necessary to better describe mortality events in relation to environmental-parameter fluctuations and OsHV-1 detection. For this purpose, a single batch of Pacific oyster spat was deployed in 4 different locations in the Marennes-Oleron area (France): an oyster pond (“claire”), a shellfish nursery, and two locations in the field. Mortality rates were recorded based on regular observation, and samples were collected to search for and quantify OsHV-1 DNA by real-time PCR. Although similar massive mortality rates were reported at the 4 sites, mortality was detected earlier in the pond and in the nursery than at both field sites. This difference may be related to earlier increases in water temperature. Mass mortality was observed among oysters a few days after increases in the number of PCR-positive oysters and viral-DNA amounts were recorded. An initial increment in the number of PCR-positive oysters was reported at both field sites during the survey in the absence of significant mortality. During this period, the water temperature was below 16°C.

Bactericidal Effects of Wine on Vibrio parahaemolyticus in Oysters

2006 ◽  
Vol 69 (8) ◽  
pp. 1823-1828 ◽  
Author(s):  
CHENGCHU LIU ◽  
RUIYING CHEN ◽  
YI-CHENG SU
Keyword(s):  
Vibrio Parahaemolyticus ◽  
White Wine ◽  
Most Probable Number ◽  
White Wines ◽  
Probable Number ◽  
Wine Consumption ◽  
Log Reduction ◽  
Bactericidal Effects

The bactericidal effects of wines on Vibrio parahaemolyticus in oysters were studied to evaluate potential inactivation of V. parahaemolyticus in contaminated oysters by wine consumption. Shucked whole oyster and oyster meat homogenate were inoculated with V. parahaemolyticus and mixed with red or white wine. Survivals of V. parahaemolyticus in inoculated oysters were determined at 7 and 25°C. Populations of V. parahaemolyticus in inoculated whole oysters (5.52 log most probable number [MPN] per g) decreased slightly to 4.90 log MPN/g (a 0.62-log reduction) after 24 h at 7°C but increased to 7.37 log MPN/g over the same period at 25°C. However, the populations in wine-treated whole oysters decreased by >1.7 and >1.9 log MPN/g after 24 h at 7 and 25°C, respectively. Both red and white wines were more effective in inactivating V. parahaemolyticus in oyster meat homogenate than in whole oyster. Populations of V. parahaemolyticus in oyster meat homogenate (7.8 × 103 MPN/g) decreased rapidly to nondetectable levels (<3 MPN/g) after 30 min of mixing with wine at 25°C (a 3.89-log MPN/g reduction). These results suggest that chewing oysters before swallowing when eating raw oysters may result in greater inactivation of V. parahaemolyticus if wine is consumed. More studies are needed to determine the bactericidal effects of wine on V. parahaemolyticus in the complicated stomach environment.

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