title: Inactivation of hepatitis A virus by high-pressure processing: the role of temperature and pressure oscillation.
abstract: Inactivation of hepatitis A virus (HAV) in Dulbecco's modified Eagle medium with 10% fetal bovine serum was studied at pressures of 300, 350, and 400 MPa and initial sample temperatures of -10, 0, 5, 10, 20, 30, 40, and 50 degrees C. Sample temperature during pressure application strongly influenced the efficiency of HAV inactivation. Elevated temperature (> 30 degrees C) enhanced pressure inactivation of HAV, while lower temperatures resulted in less inactivation. For example, 1-min treatments of 400 MPa at -10, 20, and 50 degrees C reduced titers of HAV by 1.0, 2.5, and 4.7 log PFU/ml, respectively. Pressure inactivation curves of HAV were obtained at 400 MPa and three temperatures (-10, 20, and 50 degrees C). With increasing treatment time, all three temperatures showed a rapid initial drop in virus titer with a diminishing inactivation rate (or tailing effect). Analysis of inactivation data indicated that the Weibull model more adequately fitted the inactivation curves than the linear model. Oscillatory high-pressure processing for 2, 4, 6, and 8 cycles at 400 MPa and temperatures of 20 and 50 degrees C did not considerably enhance pressure inactivation of HAV as compared with continuous high-pressure application. These results indicate that HAV exhibits, unlike other viruses examined to date, a reduced sensitivity to high pressure observed at cooler treatment temperatures. This work suggested that slightly elevated temperatures are advantageous for pressure inactivation of HAV within foods.
authors.affiliation: U.S. Department of Agriculture, Agricultural Research Service, Microbial Food Safety Research Unit, James W. W. Baker Center, Delaware State University, Dover, Delaware 19901, USA.
authors.forename: David H
authors.initials: DH
authors.lastname: Kingsley
authors.forename: Dongsheng
authors.initials: D
authors.lastname: Guan
authors.forename: Dallas G
authors.initials: DG
authors.lastname: Hoover
authors.forename: Haiqiang
authors.initials: H
authors.lastname: Chen
mesh_terms: D000818:Animals; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D005516:Food Microbiology; D030041:Hepatitis A virus / Q000254:growth & development*; D006801:Humans; D006874:Hydrostatic Pressure; D008954:Models, Biological; D011237:Predictive Value of Tests; D018709:Statistics, Nonparametric; D013696:Temperature; D013997:Time Factors; D038301:Virus Inactivation