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Predictive models for the effect of storage temperature on Vibrio parahaemolyticus viability and counts of total viable bacteria in Pacific oysters (Crassostrea gigas)
journal contribution
posted on 2023-05-17, 09:59 authored by Fernandez-Piquer, J, John BowmanJohn Bowman, Thomas RossThomas Ross, Mark TamplinMark TamplinVibrio parahaemolyticus is 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 of V. parahaemolyticus strains, measuring viability rates at storage temperatures from 3.6 to 30.4 Celsius degree, 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 of V. parahaemolyticus. V. parahaemolyticus viability was measured by direct plating samples on thiosulfate-citratebile 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 for V. parahaemolyticus were -0.006, -0.004, -0.005, -0.003, 0.030, 0.075, 0.095, and 0.282 log10 CFU/h at 3.6, 6.2, 9.6, 12.6, 18.4, 20.0, 25.7, and 30.4 Celsius degree, respectively. The growth rates for TVC were 0.015, 0.023, 0.016, 0.048, 0.055, 0.071, 0.133, and 0.135 log10 CFU/h at 3.6, 6.2, 9.3, 14.9, 18.4, 20.0, 25.7, and 30.4 Celsius degree, respectively. Square root and Arrhenius-type secondary models were generated for V. parahaemolyticus growth and inactivation kinetic data, respectively. A square root model was produced for TVC growth. Evaluation studies showed that predictive growth for V. parahaemolyticus and TVC were "fail safe." The models can assist oyster companies and regulators in implementing management strategies to minimize V. parahaemolyticus risk and enhancing product quality in supply chains.
Funding
Australian Seafood Cooperative Research Centre
History
Publication title
Applied and Environmental MicrobiologyVolume
77Issue
24Pagination
8687-8695ISSN
0099-2240Department/School
Tasmanian Institute of Agriculture (TIA)Publisher
Amer Soc MicrobiologyPlace of publication
1752 N St Nw, Washington, USA, Dc, 20036-2904Rights statement
Copyright 2011 American Society for MicrobiologyRepository Status
- Restricted