Submitted to: International Journal of Food Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/10/2005
Publication Date: 4/1/2006
Citation: Swayne, D.E., Beck, J.R. 2006. Microassay for measuring thermal inactivation of H5N1 high pathogenicity Avian Influenza virus in naturally-infected chicken meat. International Journal of Food Microbiology 108(2):268-271. Interpretive Summary: High pathogenicity avian influenza (HPAI) virus can be in meat of infected chickens. A precise method was developed to measure the killing of HPAI virus during cooking. No HPAI virus was found in chicken meat cooked for 5 seconds or longer at 70C. The assay used very small samples of meat, and produced accurate and reproducible results.
Technical Abstract: A precise, reproducible microassay was developed to measure thermal inactivation of high pathogenicity avian influenza (HPAI) virus in chicken meat. Small pieces of breast or thigh meat (0.05 g) from chickens infected with A/chicken/Pennsylvania/1370/1983 (H5N2) (PA/83) or A/chicken/Korea/ES/2003 (H5N1) (Korea/03) HPAI viruses were tested for inactivation in a heat block system of a thermocycler. Korea/03 infected thigh and breast meat had higher virus concentrations (6.8 log 10 and 5.6 log 10 mean embryo infectious doses [EID50]/g, respectively) compared to PA/83 infected thigh and breast meat (2.8 log 10 and 2.3 log 10 EID50/g, respectively). The samples were ran through a ramp-up cycle from 25-70C, and samples were removed and examined for virus infectivity at 30, 40, 50, 60 and 70C, and after treatment for 1, 5, 10, 30 and 60 s at 70C. The reduction in virus infectivity titers was dependent on virus concentration and no HPAI virus was isolated after 1 s of treatment at 70C. A change in coloration from pink-tan to white was associated with a loss in recovery of infectious virus. The microassay provided a predictable and reproducible method to measure thermal inactivation of HPAI virus in chicken meat.