Submitted to: International Association for Food Protection
Publication Type: Abstract Only
Publication Acceptance Date: 3/9/2006
Publication Date: 8/11/2006
Citation: Thomas, C., Swayne, D.E. 2006. Thermal inactivation of Newcastle disease virus (ulster strain) in chicken meat: determination of D and Z values [abstract]. In: Proceedings of Annual Meeting of International Association for Food Protection. p. 124. Interpretive Summary:
Technical Abstract: Newcastle disease (ND) viruses and avian influenza (AI) viruses cause respiratory or intestinal infections in chickens and other gallinaceous birds. Some virulent ND viruses and some highly pathogenic AI viruses can cause systemic infections and replicate to high titers in skeletal muscle fibers. To prevent transmission of these viruses through contaminated meat, the World Organization for Animal Health (OIE) recommends trading poultry products from countries, zones, or compartments infected with ND or certain AI virus subtypes only when the products are effectively processed to destroy these pathogens. ND and AI viruses are heat-labile and will be inactivated in sufficiently cooked poultry meat, but more studies are needed to determine thermal processing guidelines. For this study, thermal death calculations were performed for a model low-virulence ND virus (Ulster strain) in chicken meat. Small (0.05 g) pieces of breast meat were artificially infected with virus (107.5 to 108.5 EID50 per g of meat) and heated in a thermocycler block. Meat samples were ground with small pestles to release virus from the tissue, and the supernatants were tested for virus inactivation by titration in embryonating chicken eggs. The time required for a 90% reduction in virus titer (Dt value) was calculated for temperatures of 57, 58, 59, and 61 ºC. Dt values were inversely related to temperature, and ranged from 38.1 seconds at 61 ºC to 472.1 seconds at 57 ºC. The temperature increase required for a 90% reduction in thermal death time was 3.7 ºC. These results indicate that current USDA performance standards for a 7.0 log10 reduction of Salmonella in ready-to-eat poultry meat products are sufficient to inactivate high titers of a low-virulence ND virus in chicken breast. Future studies will determine whether this is also the case for virulent ND viruses and highly pathogenic AI viruses.