Effects of Flash Freezing, Followed by Frozen Storage, on Reducing Vibrio parahaemolyticus in Pacific Raw Oysters (Crassostrea gigas)
Abstract:This study investigated the effects of flash freezing, followed by frozen storage, on reducing Vibrio parahaemolyticus in Pacific raw oysters. Raw Pacific oysters were inoculated with a five-strain cocktail of V. parahaemolyticus at a total level of approximately 3.5 × 105 most probable number (MPN) per gram. Inoculated oysters were subjected to an ultralow flash-freezing process (−95.5°C for 12 min) and stored at −10, −20, and −30°C for 6 months. Populations of V. parahaemolyticus in the oysters declined slightly by 0.22 log MPN/g after the freezing process. Subsequent storage of frozen oysters at −10, −20, and −30°C resulted in considerable reductions of V. parahaemolyticus in the oysters. Storing oysters at −10°C was more effective in inactivating V. parahaemolyticus than was storage at −20 or −30°C. Populations of V. parahaemolyticus in the oysters declined by 2.45, 1.71, and 1.45 log MPN/g after 1 month of storage at −10, −20, and −30°C, respectively, and continued to decline during the storage. The levels of V. parahaemolyticus in oysters were reduced by 4.55, 4.13, and 2.53 log MPN/g after 6 months of storage at −10, −20, and −30°C, respectively. Three process validations, each separated by 1 week and conducted according to the National Shellfish Sanitation Program's postharvest processing validation–verification interim guidance for Vibrio vulnificus and Vibrio parahaemolyticus, confirmed that a process of flash freezing, followed by storage at −21 ±2°C for 5 months, was capable of achieving greater than 3.52-log (MPN/g) reductions of V. parahaemolyticus in half-shell Pacific oysters.
Document Type: Research Article
Affiliations: 1: College of Food Science and Technology, Shanghai Ocean University, Shanghai, 200090, People's Republic of China 2: Seafood Research and Education Center, Oregon State University, Astoria, Oregon 97103, USA
Publication date: January 1, 2009
- IAFP Members with personal subscriptions to JFP Online: To access full-text JFP or JMFT articles, you must sign-in in the upper-right corner using your Ingenta sign-in details (your IAFP Member Login does not apply to this website). The Journal of Food Protection (JFP) is a refereed monthly publication. Each issue contains scientific research and authoritative review articles reporting on a variety of topics in food science pertaining to food safety and quality. The Journal is internationally recognized as the leading publication in the field of food microbiology with a readership exceeding 11,000 scientists from 70 countries. The Journal of Food Protection is indexed in Index Medicus, Current Contents, BIOSIS, PubMed, Medline, and many others.
Print and online subscriptions are available to IAFP Members and institutional subscribers. IAFP Members with a subscription to JFP Online will have access to all available JFP and JMFT content. Online visitors who are not IAFP Members or journal subscribers will be charged on a pay-per-view basis. Membership and subscription information is available at www.foodprotection.org.
- Information for Authors
- Submit a Paper
- Subscribe to this Title
- Membership Information
- Information for Advertisers
- ingentaconnect is not responsible for the content or availability of external websites