title: Evaluation of Ice Slurries as a Control for Postharvest Growth of Vibrio spp. in Oysters and Potential for Filth Contamination.
abstract: Raw oyster consumption is the most common route of exposure for Vibrio spp. infections in humans. Vibriosis has been increasing steadily in the United States despite efforts to reduce the incidence of the disease. Research has demonstrated that ice is effective in reducing postharvest Vibrio spp. growth in oysters but has raised concerns of possible contamination of oyster meat by filth (as indicated by the presence of fecal coliform bacteria or Clostridium perfringens). This study examined the use of ice slurries (<4.5°C) to reduce Vibrio growth. Ice slurries showed rapid internal cooling of oysters, from 23.9°C (75°F) to 10°C (50°F) within 12 min. The initial bacterial loads in the ice slurry waters were near the limits of detection. Following repeated dipping of oysters into ice slurries, water samples exhibited significant (P < 0.05) increases in median levels of fecal coliforms (9.5 most probable number [MPN]/100 ml), C. perfringens (280 MPN/100 ml), Vibrio vulnificus (11,250 MPN/ml), and total Vibrio parahaemolyticus (3,900 MPN/ml). The microbial load in oyster meat, however, was unchanged after 15 min of submergence, with no significant differences (P < 0.05) in levels of filth indicator (range, 250 to 720 MPN/100 g) or Vibrio spp. (range, 9,000 to 20,000 MPN/g) bacteria. These results support the use of ice slurries as a postharvest application for rapid cooling of oysters to minimize Vibrio growth.
authors.affiliation: U.S. Food and Drug Administration, Division of Seafood Science and Technology, Gulf Coast Seafood Laboratory, Dauphin Island, Alabama 36528, USA; Department of Environmental Health Science, College of Public Health, University of Georgia, Athens, GA 30602, USA.
authors.forename: Keri Ann
authors.initials: KA
authors.lastname: Lydon
authors.affiliation: U.S. Food and Drug Administration, Division of Seafood Safety, College Park, Maryland 20740, USA.
authors.forename: Melissa
authors.initials: M
authors.lastname: Farrell-Evans
authors.affiliation: U.S. Food and Drug Administration, Division of Seafood Science and Technology, Gulf Coast Seafood Laboratory, Dauphin Island, Alabama 36528, USA. Jessica.Jones@fda.hhs.gov.
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Jones
mesh_terms: D000818:Animals; D005506:Food Contamination / Q000032:analysis / Q000517:prevention & control*; D005519:Food Preservation / Q000295:instrumentation / Q000379:methods*; D007053:Ice / Q000032:analysis*; D010125:Ostreidae / Q000382:microbiology*; D012758:Shellfish / Q000382:microbiology*; D014481:United States; D014736:Vibrio parahaemolyticus / Q000254:growth & development* / Q000302:isolation & purification; D041261:Vibrio vulnificus / Q000254:growth & development* / Q000302:isolation & purification
chemical_list: D007053:Ice