title: Validation of high pressure processing for inactivating Vibrio parahaemolyticus in Pacific oysters (Crassostrea gigas).
abstract: This study identified and validated high hydrostatic pressure processing (HPP) for achieving greater than 3.52-log reductions of Vibrio parahaemolyticus in the Pacific oysters (Crassostrea gigas) and determined shelf life of processed oysters stored at 5°C or in ice. Raw Pacific oysters were inoculated with a clinical strain of V. parahaemolyticus 10293 (O1:K56) to levels of 10(4-5) cells per gram and processed at 293 MPa (43 K PSI) for 90, 120, 150, 180 and 210 s. Populations of V. parahaemolyticus in oysters after processes were analyzed with the 5-tube most probable number (MPN) method. Negative results obtained by the MPN method were confirmed with a multiplex PCR detecting genes encoding thermolabile hemolysin (tl), thermostable direct hemolysin (tdh) and TDH-related hemolysin (trh). A HPP of 293 MPa for 120 s at groundwater temperature (8±1°C) was identified capable of achieving greater than 3.52-log reductions of V. parahaemolyticus in Pacific oysters. Oysters processed at 293 MPa for 120 s had a shelf life of 6-8 days when stored at 5°C or 16-18 days when stored in ice. This HPP can be adopted by the shellfish industry as a post harvest process to eliminate V. parahaemolyticus in raw oysters.
authors.affiliation: Seafood Research and Education Center, Oregon State University, 2001 Marine Drive, Room 253, Astoria, OR 97103, USA.
authors.forename: Lei
authors.initials: L
authors.lastname: Ma
authors.forename: Yi-Cheng
authors.initials: YC
authors.lastname: Su
mesh_terms: D000818:Animals; D015169:Colony Count, Microbial; D049896:Crassostrea / Q000382:microbiology*; D005516:Food Microbiology / Q000379:methods*; D050296:Microbial Viability; D011312:Pressure; D013696:Temperature; D013997:Time Factors; D014736:Vibrio parahaemolyticus / Q000235:genetics / Q000502:physiology*