Modeling the Effect of Storage Temperature on the Growth, Survival, and Inactivation of Vibrio cholerae Pacini and Total Viable Bacteria in Post-harvested Pacific White Shrimps (Litopenaeus vannamei Boone)

Introduction: Vibrio cholerae are natural flora of marine environment.  They are commonly associated with seafood and may reach levels that cause human disease when postharvest temperatures are not properly controlled and are consumed raw or undercooked. 

Purpose: Predictive models were generated by inoculating pacific white shrimps with V. cholerae, measuring viability rates at storage temperatures from 0 to 35°C, and fitting the data to a model to estimate growth parameters. 

Methods: The models were evaluated with pacific white shrimps containing natural populations of V. cholerae. Viable V. cholerae was measured by pour plate method on thiosulfate-citrate-bile salts-sucrose agar for both inoculated and naturally contaminated shrimp samples.  In parallel, total viable bacterial counts were measured by pour plate method on plate count agar. 

Results: Growth/inactivation rates for V. cholerae were -0.008, -0.005, -0.002, 0.065, 0.125, and 0.252 log CFU/h at 0, 5, 10, 20, 30, and 35°C, respectively.  The growth/inactivation rates for total viable bacteria were 0.007, 0.011, 0.024, 0.078, 0.130, and 0.322 log CFU/h at 0, 5, 10, 20, 30 and 35°C.  Square root and Arrhenius models were generated for V. cholerae and total viable bacterial growth and inactivation kinetic data, respectively. 

Significance: Evaluation studies showed that predictive growth for V. cholerae and total viable bacterial count were “fail-safe.”  The models can be used by aquaculture establishments and regulators in implementing management strategies to minimize V. cholerae risk and enhancing product quality in supply chains.