Molluscan shellfish depuration

Schneider, Kimberly; Cevallos, José Pontón; Rodrick, Gary E.

doi:10.1533/9781845695576.5.509

Cited by 12 publications

(15 citation statements)

References 25 publications

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“…Along with this, the size and physical condition of bivalves, initial loads of bacterial strains and environmental conditions (temperature, salinity, pH, etc. ), are the other important parameters affecting the depuration process of this bacteria ( Joven et al , 2011 ; Schneider et al , 2009 ).…”

Section: Resultsmentioning

confidence: 99%

“…The seawater should also be cleaned and disinfected by various treatments such as UV, ozonation, and filtration to achieve successful purification of shellfishes. Moreover, effectiveness of the depuration process also depends on the diversity and physiology of shellfishes along with characteristics of water and the system ( Schneider et al , 2009 ).…”

Section: Introductionmentioning

confidence: 99%

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Depuration Times of Donax trunculus and Tapes decussatus

Çolakolu

Çardak

Çolakoğlu

et al. 2014

Braz. J. Microbiol.

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The present study was performed to determine the depuration time and ability of Donax trunculus (Wedge Clam) and Tapes decussatus (Carpet Shell) contaminated with Escherichia coli, Salmonella enterica subsp. enterica serovar Typhimurium and Vibrio parahaemolyticus. Clams were contaminated with each bacterium at the level of 7.0 – 8.0 Log10 cfu/g. After contamination, clams were analyzed every 3 h in the first 24 h time period and every 6 h until the 72nd hour. During the depuration process of both clams, the level of bacteria decreased quickly to 40% of initial load in the first 12 h. The results of this study indicate that the depuration time of carpet shells for all bacteria is 66 h. The depuration process of the wedge clam was different from the carpet shell; S. typhimurium and E. coli can be depurated in 66 and 78 h, respectively, while V. parahaemolyticus was present after 72 h at the level of 1.7 Log10 cfu/g.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Depuration Times of Donax trunculus and Tapes decussatus

Çolakolu

Çardak

Çolakoğlu

et al. 2014

Braz. J. Microbiol.

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“…The depurating process represents a metabolic effort/fitness that could compromise bivalve’ viability, especially when the suspended food particles are scarce or under stressful conditions ( Antunes et al, 2010 ). Moreover, this ability may explain why artificially contaminated mollusks depurate more rapidly than environmentally contaminated ones ( Jones et al, 1991 ; Schneider et al, 2009 ). Generally, bacteria are rapidly reduced in shellfish by using seawater only.…”

Section: Discussionmentioning

confidence: 99%

“…Because residual levels of ozone and the superchilled air storage may cause the shellfish to decrease or inhibit normal activity by cessation of mantle and shell movements ( Schneider et al, 2009 ), reducing the effectiveness of the process, survival and pH were monitored as pH is an indicator of death ( Aaraas et al, 2004 ). A 40-oyster sample from the control and from each repetition tank randomly collected was used to assess the survival of oysters after the 6 h depuration and throughout the time of superchilled storage.…”

Section: Methodsmentioning

confidence: 99%

“…To improve their microbiological safety, raw mollusks are often depurated by placing them in controlled, sanitized seawater allowing them to purge contaminants from their tissues by means of their natural pumping activity. The effectiveness of the depuration process depends on the diversity and physiology of the particular mollusk species as well as on water and system characteristics ( Schneider et al, 2009 ). Depuration systems consist of flow-through, or closed, recirculation with chemically (chlorine and/or ozone) or physically (UV irradiation) disinfected water to eliminate bacteria and other pathogens and spoilage microorganisms.…”

Section: Introductionmentioning

confidence: 99%

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Improved Microbial Safety of Direct Ozone-Depurated Shellstock Eastern Oysters (Crassostrea virginica) by Superchilled Storage

et al. 2018

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The effect of superchilled storage at -1°C on the microbial safety of oyster depurated with 0.2, 0.4, and 0.6 mg/L ozone was studied for 14 days. Fecal coliforms (4,100–16,000 MPN/100 g), Escherichia coli (1,500–3,650 MPN/100 g), Vibrio cholerae non-O1/non-O139 (13.0–102.0 MPN/g), and Salmonella spp. (2.270–3.035 × 103 CFU/g) were initially present in raw oysters. After 6 h depuration, fecal coliform counts decreased (P < 0.05) to 300, 20 and 20 MPN/100 g for 0.2, 0.4, and 0.6 mg/L treatments, while a 0.3 log decrease in control oysters was observed. Initial E. coli counts decreased (P < 0.05) in oysters to 50, 20, and 20 MPN/100 g for 0.2, 0.4, and 0.6 mg/L treatments, respectively. A 1 log reduction in V. cholerae non-O1/non-139 levels were observed in 0.4 and 0.6 mg/L-treatments after 2 and 4 h depuration. Salmonella spp. was not detected in oyster samples after 6 h depuration in 0.4 and 0.6 mg/L-ozone treatments. Considering the bacterial loads after depuration, at the end of superchilled storage the 0.4 mg/L-ozonated oysters attained lower (P < 0.05) fecal coliform levels (280 MPN/100 g) and E. coli counts in 0.4 and 0.6 mg/L-ozonated oysters (20 and 95 MPN/100 g, respectively). A 2-log decrease in V. cholerae non-O1/non-O139 levels on day 5 in 0.4 and 0.6 mg/L-ozonated oysters (< 0.3 MPN/g) was attained. V. cholerae non-O1/non-O139 counts in control oysters decreased 1 log on day 9 of superchilled storage. Salmonella spp. was not detected in ozonated and superchilled stored oysters. Levels of fecal coliforms, E. coli, Salmonella spp., and V. cholerae non-O1/non-O139 in non-ozone depurated oyster samples were higher than in control, 0.4 and 0.6 mg/L ozonated oyster samples during superchilled storage. The cumulative mortality rates after 14 days of storage for superchilled oysters (22.2%) was higher (P < 0.05) than 0.6 mg/L O3 (7.2%) and 0.4 mg/L O3 (5.8%) treatments, and control oysters (5.6%). pH values in control oysters decreased significantly (P < 0.05) throughout the storage period but not in oysters of both ozone treatments, indicating no detrimental effects on oyster survival. The results of this study suggest that superchilled storage enables ozonated shellstock oysters (0.4 mg/L-6 h) stored for 9 days to be safe human consumption.

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Simultaneous isolation and enumeration of virulent Vibrio cholerae and Vibrio vulnificus using an advanced MPN-PCR method

et al. 2021

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Vibrio cholerae and Vibrio vulni cus are one of the critical foodborne pathogens that need to be intensively controlled their infection as a result of the intake and distribution of seafood, especially raw oysters. For this reason, various methods have already been developed for the detection and enumeration of these bacteria. The most probable number (MPN)-PCR (polymerase chain reaction) method is commonly used with the selective-differential medium for the e ciency and convenience of cell enumeration. One of the most frequently used for the detection of Vibrio spp. is Thiosulfate-Citrate-Bile salts-Sucrose (TCBS) agar. But this selective-differential medium can fail to distinguish between V. cholerae, V. vulni cus, and Vibrio alginolyticus. For this reason, the conventional MPN-PCR method with TCBS medium for the detection of Vibrio spp. has a problem that processing PCR to the two-times. This study suggests a simple and minimized detection method using one-time PCR and non-NaCl Luria-Bertani (LB-0) medium culture. This detection method is based on the difference in salt requirement between V. cholerae and V. vulni cus. Employing the developed methodology, the simultaneous cell enumeration of V. cholerae and V. vulni cus can be possible at a low cost. Furthermore, this study proposes a new speci c primer to detect virulence-related genes from V. cholerae and V. vulni cus. This advanced MPN-PCR method was veri ed using bioaccumulated paci c oysters (Crassostrea gigas) by V. cholerae and V. vulni cus.

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Molluscan shellfish depuration

Cited by 12 publications

References 25 publications

Depuration Times of Donax trunculus and Tapes decussatus

Depuration Times of Donax trunculus and Tapes decussatus

Improved Microbial Safety of Direct Ozone-Depurated Shellstock Eastern Oysters (Crassostrea virginica) by Superchilled Storage

Simultaneous isolation and enumeration of virulent Vibrio cholerae and Vibrio vulnificus using an advanced MPN-PCR method

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