title: High Salinity Relaying to Reduce Vibrio parahaemolyticus and Vibrio vulnificus in Chesapeake Bay Oysters (Crassostrea virginica).
abstract: Cases of Vibrio infections in the United States have tripled from 1996 to 2009 and these infections are most often associated with the consumption of seafood, particularly oysters (Crassostrea virginica). Information is needed on how to reduce numbers of Vibrio parahaemolyticus and Vibrio vulnificus in bi-valve molluscan shellfish (for example, oysters). The purpose of this study was to evaluate the effectiveness of high salinity relaying or treatment in recirculating aquaculture systems (RASs) as methods to reduce the abundance of V. parahaemolyticus and V. vulnificus in oysters. For relaying field trials, oysters were collected from approved harvest waters, temperature abused outside under a tarp for 4 h, and then transferred to high (29 to 33 ppt.) and moderate (12 to 19 ppt.) salinities. For RAS treatment trial, oysters were transferred to 32 to 34 ppt. salinity at 15 °C. After 7, 14, 21, and in some instances 28 d, oysters were collected and analyzed for V. parahaemolyticus and V. vulnificus levels using multiplex real-time PCR. Initial levels of V. parahaemolyticus and V. vulnificus ranged from 3.70 to 5.64 log10MPN/g, and were reduced by 2 to 5 logs after 21 to 28 d in high salinity water (29 to 34 ppt.). Oyster mortalities averaged 4% or less, and did not exceed 7%. Relaying of oysters to high salinity field sites or transfer to high salinity RAS tanks was more effective in reducing V. vulnificus compared with V. parahaemolyticus. These results suggest that high salinity relaying of oysters is more effective in reducing V. vulnificus than V. parahaemolyticus in the oyster species used in this study.
authors.affiliation: Univ. of Maryland Eastern Shore, Princess Anne, MD, 21853, U.S.A.
authors.forename: Salina
authors.initials: S
authors.lastname: Parveen
authors.affiliation: Virginia Tech., Virginia Seafood Agricultural Research and Extension Center, Hampton, VA, 23669, U.S.A.
authors.forename: Michael
authors.initials: M
authors.lastname: Jahncke
authors.affiliation: Univ. of Maryland Eastern Shore, Princess Anne, MD, 21853, U.S.A.
authors.forename: Sara
authors.initials: S
authors.lastname: Elmahdi
authors.affiliation: Virginia Tech., Virginia Seafood Agricultural Research and Extension Center, Hampton, VA, 23669, U.S.A.
authors.forename: Helen
authors.initials: H
authors.lastname: Crocker
authors.affiliation: U.S. FDA, Center for Food Safety and Applied Nutrition, College Park, MD, 20740, U.S.A.
authors.forename: John
authors.initials: J
authors.lastname: Bowers
authors.affiliation: Univ. of Maryland Eastern Shore, Princess Anne, MD, 21853, U.S.A.
authors.forename: Chanelle
authors.initials: C
authors.lastname: White
authors.affiliation: Virginia Tech., Virginia Seafood Agricultural Research and Extension Center, Hampton, VA, 23669, U.S.A.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Gray
authors.affiliation: Virginia Tech., Virginia Seafood Agricultural Research and Extension Center, Hampton, VA, 23669, U.S.A.
authors.forename: Amanda C
authors.initials: AC
authors.lastname: Morris
authors.affiliation: Maryland Dept. of the Environment, Baltimore, MD, 21230, U.S.A.
authors.forename: Kathy
authors.initials: K
authors.lastname: Brohawn
mesh_terms: D000818:Animals; D017756:Aquaculture; D061006:Bays; D015169:Colony Count, Microbial; D049896:Crassostrea / Q000382:microbiology*; D005504:Food Analysis / Q000379:methods*; D005506:Food Contamination / Q000517:prevention & control*; D005843:Geography; D008396:Maryland; D010125:Ostreidae / Q000382:microbiology; D054712:Salinity; D017747:Seafood / Q000032:analysis / Q000382:microbiology; D012758:Shellfish / Q000032:analysis / Q000382:microbiology; D013696:Temperature; D014735:Vibrio Infections; D014736:Vibrio parahaemolyticus / Q000472:pathogenicity*; D041261:Vibrio vulnificus / Q000472:pathogenicity*; D014768:Virginia
keywords: Oyster; Vibrio; high salinity; relaying; seafood safety