Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/1/2004
Publication Date: 7/1/2004
Citation: Kingsley, D.H., Calci, K., Hoover, D. 2004. High hydrostatic pressure as an intervention strategy for virus-contaminated shellfish. American Society for Virology. P33-1. pg. 266. Interpretive Summary:
Technical Abstract: High hydrostatic pressure processing (HPP) has emerged as an alternative bacterial sanitization method for raw shellfish. The principal advantage of HPP is that it retains the uncooked character of shellfish while facilitating the shucking process. Uncooked oysters, treated at pressures of up to 400 MPA (1 MPa = 10.2 atm), are acceptable to raw shellfish consumers and are commercially available. To investigate HPP's utility for virus sanitization, evaluation of feline calicivirus (a norovirus surrogate) and several picornaviruses was performed. The evaluated picornaviruses included hepatitis A virus (HAV), Aichi virus, coxsackieviruses A9 and B5, and human parechovirus-1. Overall, a variable pattern of pressure-induced inactivation was observed. A 7-log10 tissue culture infectious dose 50%(TCID50) feline calicivirus stock was completely inactivated (>6 log10 reduction)after 5-min treatments of 275 MPa. For a 7-log10 PFU HAV stock, titer reduction was observed at 325 MPa, with complete inactivation observed at 460 MPa. For coxsackie A9, five-min treatments at 400, 500, and 600 MPa resulted in log10 TCID reductions of 3.4, 6.5 and 7.6, respectively. For human parechovirus-1, 5-min treatments at 400, 500, and 600 MPa reduced titers by 1.3-, 4.3-, and 4.6-log10 TCID50, respectively. However, Aichi virus and coxsackievirus B5 were completely resistant to 5-min treatments at 600 MPa demonstrating no significant reduction. Since pressure inactivation of viruses can potentially be influenced by food composition (e.g. ionic strength, fat content, pH), live oysters were exposed to HAV-contaminated seawater, treated for 1 min at different pressures, followed by HAV extraction and plaque assay. Reductions of> 1-, > 2-, > 3-log10 HAV were observed after 1-min treatments at 350, 375, and 400 MPa, respectively. In total, this work indicates that HPP will probably not have broad utility for all viruses which could potentially contaminate raw oysters since human parechovirus-1 inactivation requires pressures greater than 400 MPa, and Aichi and coxsackie B5 viruses are resistant to 600 MPa. For the two most common viral agents associated with shellfish consumption, HAV and norovirus, HPP should have utility assuming noroviruses are as sensitive to pressure as feline calicivirus.