Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 4, 2008
Publication Date: April 1, 2009
Citation: Porto Fett, A.C., Call, J.E., Luchansky, J.B. 2009. VALIDATION OF A COMMERCIAL PROCESS FOR INACTIVATION OF ESCHERICHIA COLI O157:H7, SALMONELLA, AND LISTERIA MONOCYTOGENES ON THE SURFACE OF WHOLE MUSCLE BEEF JERKY STRIPS. Journal of Food Protection. 71(5):918-926. Interpretive Summary: In this study we validated a commercial process for its ability to kill foodborne bacterial pathogens on the surface of whole-muscle beef jerky strips. Escherichia coli O157:H7, Salmonella, or Listeria monocytogenes (about 100 million bacteria) were applied to the surface of beef strips. In addition, beef strips were either treated with or without a marinade that was applied to the surface. Following the addition of the bacterial pathogens and the marinade, the beef strips were placed on the top, middle, and bottom levels of a loading rack and subsequently loaded into a smokehouse that was filled with hickory smoke and cooked/dried at 180 degree F for 1.5, 2.5 or 3.5 hours. Regardless of how the strips were treated or inoculated or where the strips were placed on the loading rack, drying for 1.5, 2.5 or 3.5 hours at 180 deg F with hickory smoke was sufficient to kill great than 99.99% of the bacterial pathogens. The results of this study will help manufacturers who cook/dry their product at higher temperatures (greater than or equal to 180 deg F) for shorter periods of time to meet the current government guidelines for processing a safe beef jerky product.
Technical Abstract: Evaporative cooling at the surface of beef jerky during drying may result in insufficient lethality of pathogens. Thus, we validated the lethality of time and temperature regimens for commercial processing of whole-muscle beef jerky. A total of ca. 8.0 log10 CFU of multiple-strain cocktails of Escherichia coli O157:H7, Salmonella spp., or Listeria monocytogenes were separately applied to the surface of beef strips and treated as follows: i) not marinated and inoculated, ii) marinated in a vacuum tumbler and then inoculated, or iii) inoculated and then marinated by hand. A total of three beef strips for each treatment were separately inoculated with a cocktail of one of the three pathogens and placed on the top, middle, and bottom levels of a loading rack. The strips on the rack were loaded into a smokehouse and cooked/dried for either 1.5, 2.5 or 3.5 hours at 180 deg F with constant smoke. Regardless of how the strips were treated or inoculated or where the strips were placed on the loading rack, drying for 1.5, 2.5 or 3.5 hours at 180 deg F with constant smoke resulted in a decrease of at least 6.5 log10 CFU per strip of each of the three pathogen cocktails.