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Inactivation of infectious hepatitis E virus present in commercial pig livers sold in local grocery stores in the United States

Feagins, A.R., Opriessnig, T., Guenette, D.K., Halbur, P.G., Meng, X.J.
International journal of food microbiology 2008 v.123 no.1-2 pp. 32-37
Hepatitis E virus, virus transmission, swine, commercial farms, grocery stores, zoonoses, food pathogens, foodborne illness, pathogen survival, microbial activity, microbial contamination, swine diseases, food contamination, cooking, bioassays, disease control, disease incidence, food quality, livers as food, United States
Hepatitis E virus (HEV) is a zoonotic pathogen and pigs are a known reservoir. Recently we showed that approximately 11% of commercial pig livers sold in local U.S. grocery stores for food consumptions are contaminated by infectious HEV. In this study, a swine bioassay was used to determine if the infectious HEV in contaminated commercial pig livers could be inactivated by traditional cooking methods. Group 1 pigs (n =5) were each inoculated intravenously (I.V.) with a HEV-negative liver homogenate as negative controls, group 2 pigs (n =5) were each inoculated I.V. with a pool of two HEV-positive pig liver homogenates as positive controls, groups 3, 4 and 5 pigs (n =5, each group) were each inoculated I.V. with a pool of homogenates of two HEV-positive livers incubated at 56 °C for 1 h, stir-fried at 191 °C (internal temperature of 71 °C) for 5 min or boiled in water for 5 min, respectively. As expected, the group 2 positive control pigs all became infected whereas the group 1 negative control pigs remained negative. Four of the five pigs inoculated with HEV-positive liver homogenates incubated at 56 °C for 1 h also became infected. However, pigs in groups 4 and 5 did not become infected. The results indicated that HEV in contaminated commercial pig livers can be effectively inactivated if cooked properly, although incubation at 56 °C for 1 h cannot inactivate the virus. Thus, to reduce the risk of food-borne HEV transmission, pig livers must be thoroughly cooked.