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Title: THE EFFECT OF HIGH PRESSURE PROCESSING ON EASTERN OYSTERS (CRASSOSTREA VIRGINICA) EXPERIMENTALLY INFECTED WITH CRYPTOSPORIDIUM PARVUM

Author
item COLLINS, MARINA - VIRGINIA TECH
item FLICK, GEORGE - VIRGINIA TECH
item SMITH, STEPHEN - VIRGINIA TECH
item Fayer, Ronald
item CROONENBERGHS, ROBERT - VA DEPT. OF HEALTH
item O'KEEFE, SEAN - VIRGINIA TECH
item LINDSAY, DAVID - VIRGINIA TECH

Submitted to: Journal of Eukaryotic Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/15/2005
Publication Date: 11/1/2005
Citation: Collins, M.V., Flick, G.J., Smith, S.A., Fayer, R., Croonenberghs, R., O'Keefe, S., Lindsay, D.S. 2005. The effect of high pressure processing on Eastern oysters (Crassostrea virginica) experimentally infected with cryptosporidium parvum. Journal of Eukaryotic Microbiology. 52(6):500-504.

Interpretive Summary: Shellfish have been identified as a potential source of Cryptosporidium infection for humans. Inactivation of Cryptosporidium in raw shellfish would provide increased food safety for consumers. The present study tested a non-thermal alternative food processing treatment, high hydrostatic pressure processing (HPP), on the viability of Cryptosporidium oocysts in Eastern oysters artificially infected with the Beltsville strain of C. parvum. The effects of HPP were evaluated by orally exposing neonatal mice to oyster tissues and later examining them for parasite development. All pressures tested (305 to 550 MPa) were effective in reducing Cryptosporidium infectivity. The maximum decrease of infectivity (93.3%) was obtained at 550 MPa for 180 sec. This non-thermal processing treatment shows promise for commercial applications to improve safety of seafood and reduce public health risks from cryptosporidiosis.

Technical Abstract: Shellfish have been identified as a potential source of Cryptosporidium infection for humans. Inactivation of C. parvum in raw molluscan shellfish would provide increased food safety for normal and at-risk consumers. The present study tested the efficacy of a non-thermal alternative food processing treatment, high hydrostatic pressure processing (HPP), on the viability of C. parvum oocysts in Eastern oysters (Crassostrea virginica). Oysters were artificially infected with the Beltsville strain of C. parvum and subjected to HPP treatments. The effects of the treatments were evaluated by inoculation of the processed oyster tissues into neonatal mice. High pressure processing of shucked Eastern oysters at all pressures tested (305, 370, 400, 480, and 550 MPa) was significantly effective (P < 0.05) in reducing infectivity of C. parvum oocysts. A dose of 550 MPa at 180 sec of holding time produced the maximum decrease of infectivity (93.3%). Measurement of tristimulus color values of pressurized raw oysters at extended processing times from 120 sec to 360 sec at 550 MPa showed a small increase in whiteness of oyster meat. This non-thermal processing treatment shows promise for commercial applications to improve safety of seafood and reduce public health risks from cryptosporidiosis.