Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 17, 2006
Publication Date: April 11, 2007
Citation: Thomas, C., Swayne, D.E. 2007. Thermal inactivation of H5N1 high pathogenicity avian influenza virus in naturally infected chicken meat. Journal of Food Protection. 70(3):674-680. Interpretive Summary: Virus has been identified in meat from chickens, ducks, geese and Japanese quail infected with the H5N1 high pathogenicity avian influenza (HPAI) virus. This study determined that cooking temperatures were very effective for killing the virus. Furthermore, we demonstrated that the existing FSIS cooking standards for reducing Salmonella was more than sufficient to inactivating HPAI virus in breast and thigh meat from chicken infected with an H5N1 HPAI virus. Proper cooking is a safe method for elimination of multiple bacteria and viruses.
Technical Abstract: Thermal inactivation of the H5N1 high pathogenicity avian influenza (HPAI) virus strain A/chicken/Korea/ES/2003 (Korea/03) was quantitatively measured in thigh and breast meat harvested from infected chickens. The average Korea/03 titers in uncooked meat samples were 8.0 log 10 EID50/g (thigh) and 7.5 log 10 EID50/g (breast). Survival curves were constructed for Korea/03 in chicken thigh and breast meat at temperatures ranging from 57ºC to 61ºC in 1ºC intervals. Although some curves had a slightly biphasic shape, a linear model provided a fair-to-good fit at all temperatures, with R2 values of 0.85 to 0.93. Stepwise linear regression revealed that meat type did not contribute significantly to the regression model, and generated a single linear regression equation for z-value calculation and D-value prediction for Korea/03 in both meat types. The z-value and the upper limit of the 95% confidence interval for the z-value were 4.64ºC and 5.32ºC, respectively. From the lowest temperature to the highest, the predicted D-values and the upper limits of their 95% prediction intervals (conservative D-values) for 57ºC to 61ºC were: 241.2 (321.1), 146.8 (195.4), 89.3 (118.9), 54.4 (72.4), and 33.1 (44.0) seconds. D-values and conservative D-values predicted for higher temperatures were 0.28 (0.50) seconds for 70ºC and 0.041 (0.073) seconds for 73.9ºC. Calculations with the conservative D-values predicted that cooking chicken meat according to current U.S. Department of Agriculture Food Safety and Inspection Service time-temperature guidelines will inactivate Korea/03 in a heavily contaminated meat sample, such as those tested in this study, with a large margin of safety.