Title: Thermal inactivation of avian influenza virus and Newcastle disease virus in a fat-free egg product Authors
Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 3, 2011
Publication Date: July 1, 2011
Citation: Chmielewski, R.A., Beck, J.R, Swayne, D.E. 2011. Thermal inactivation of avian influenza virus and Newcastle disease virus in a fat-free egg product. Journal of Food Protection. 74(7):1161-1168. Interpretive Summary: The United States produces and exports internationally a large amount of egg product. Although the U.S. is normally free of avian influenza and Newcastle disease viruses, concern about contamination of egg product with these viruses has in the past resulted in restrictions on trade. Because these egg products are normally pasteurized, this study was performed to see if normal pasteurization times and temperatures would be effective at inactivating viruses in fat-free liquid egg product at various times and temperatures of heat processing. Fat free egg product could be categorized as either imitation egg product or liquid egg white as it contained at least 99 percent egg white. The USDA pasteurization standard for imitation egg products is 56.7 degrees C with a minimum holding time of 4.6 min while the pasteurization standard for egg white with unadjusted pH is 57.7 degrees C with a minimum holding time of 6.3 min. These pasteurization standards are based on a 5 log reduction of Salmonella. Both of these standard pasteurization processes were used to inactivate two avian influenza (AI) viruses and two Newcastle disease viruses (NDV) to determine if these pasteurization processes would adequately inactivate 100,000 virus/ ml of fat free egg product. Usage of this data in developing egg pasteurization standards for AI and NDV infected countries should allow safe trade in liquid egg products.
Technical Abstract: Avian influenza (AI) and Avian Paramyxovirus Type-1 (AMPV-1) viruses can survive on the carcasses, in organ tissue of infected birds, on fomites, and have the potential for egg transmission and egg product contamination. With the increase in global trade, there are concerns that egg products could potentially present biosecurity problems and affect international trade in liquid and dried egg products. Therefore, the generation of inactivation curves to determine thermal death times (D-value) and heat resistance of the viruses (Z-value) within fat-free egg product (FFEP) would provide valuable information in the development of risk assessment strategies. Thermal inactivation studies using A/chicken/Pennsylvania/1370/83 (H5N2) high pathogenicity AI (HPAI) virus, artificially inoculated into FFEP at 6.25 log10 mean embryo infectious doses (TID50)/ml was heat treated for 0, 1, 2, 3, 4, 6, 8, 12, 15 and sometimes up to 40 min. The resulting thermal death times D55, D56, D56.7, D57, D58, D59 values were 18.6, 8.5, 3.6, 2.5, 0.4, 0.4 min, respectively. The Z-value was 4.4 degree C. For low pathogenicity AI (LPAI) virus A/chicken/New York/13142/94 (H7N2) inoculated at 6.9 log10 TID50/ ml had D55, D56.7, D57, D58, D59, D60 values of 2.9, 1.4, 0.8, 0.7, 0.7, and 0.5 min, respectively, and a Z-value of 0.4 degree C. For virulent Newcastle disease virus (vNDV) AMPV-1/chicken/California/212676/2002 inoculated at 8.75 log10 TID50/ ml resulted in D55, D56, D56.7, D57, D58, D59 values of 12.4, 9.3, 6.2, 5, 3.7, and 1.7 min respectively. The Z-value was 4.7 degree C. While for lentogenic NDV AMPV-1/chicken/United States/B1/1948 inoculated at 8.4 log10 TID50/ ml resulted in D53, D55, D57, D58, D59, and D61 values of 5.3, 2.4, 2.3, 0.62, 0.19, and 0.17 min, respectively and a Z-value of 1.6 degree C. Usage of this data in developing egg pasteurization standards for AI and NDV infected countries should allow safe trade in liquid egg products.