title: Development and validation of a predictive model for the growth of Vibrio parahaemolyticus in post-harvest shellstock oysters.
abstract: Information is limited about the growth and survival of naturally-occurring Vibrio parahaemolyticus in live oysters under commercially relevant storage conditions harvested from different regions and in different oyster species. This study produced a predictive model for the growth of naturally-occurring V. parahaemolyticus in live Eastern oysters (Crassostrea virginica) harvested from the Chesapeake Bay, MD, USA and stored at 5-30 °C until oysters gapped. The model was validated with model-independent data collected from Eastern oysters harvested from the Chesapeake Bay and Mobile Bay, AL, USA and Asian (C. ariakensis) oysters from the Chesapeake Bay, VA, USA. The effect of harvest season, region and water condition on growth rate (GR) was also tested. At each time interval, two samples consisting of six oysters each were analyzed by a direct-plating method for total V. parahaemolyticus. The Baranyi D-model was fitted to the total V. parahaemolyticus growth and survival data. A secondary model was produced using the square root model. V. parahaemolyticus slowly inactivated at 5 and 10 °C with average rates of -0.002 and -0.001 log cfu/h, respectively. The average GRs at 15, 20, 25, and 30 °C were 0.038, 0.082, 0.228, and 0.219 log cfu/h, respectively. The bias and accuracy factors of the secondary model for model-independent data were 1.36 and 1.46 for Eastern oysters from Mobile Bay and the Chesapeake Bay, respectively. V. parahaemolyticus GRs were markedly lower in Asian oysters. Harvest temperature, salinity, region and season had no effect on GRs. The observed GRs were less than those predicted by the U.S. Food and Drug Administration's V. parahaemolyticus quantitative risk assessment.
authors.affiliation: Food Science and Technology Ph.D. Program, Department of Agriculture, Food and Resource Sciences, University of Maryland Eastern Shore, Princess Anne, MD 21853, USA. sparveen@umes.edu
authors.forename: Salina
authors.initials: S
authors.lastname: Parveen
authors.forename: Ligia
authors.initials: L
authors.lastname: DaSilva
authors.forename: Angelo
authors.initials: A
authors.lastname: DePaola
authors.forename: John
authors.initials: J
authors.lastname: Bowers
authors.forename: Chanelle
authors.initials: C
authors.lastname: White
authors.forename: Kumudini Apsara
authors.initials: KA
authors.lastname: Munasinghe
authors.forename: Kathy
authors.initials: K
authors.lastname: Brohawn
authors.forename: Meshack
authors.initials: M
authors.lastname: Mudoh
authors.forename: Mark
authors.initials: M
authors.lastname: Tamplin
mesh_terms: D000818:Animals; D049896:Crassostrea / Q000382:microbiology; D005511:Food Handling; D005516:Food Microbiology; D008954:Models, Biological; D010125:Ostreidae / Q000382:microbiology*; D015203:Reproducibility of Results; D012621:Seasons; D013696:Temperature; D013997:Time Factors; D014481:United States; D014736:Vibrio parahaemolyticus / Q000254:growth & development*