Title: Validation of fermentation and cooking parameters for dry-fermented sausage to control Shiga toxin-producing Escherichia coli (STEC) Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 15, 2013
Publication Date: May 28, 2013
Citation: Shane, L., Foster-Bey, L., Shoyer, B.A., Porto Fett, A.C., Luchansky, J.B. 2013. Validation of fermentation and cooking parameters for dry-fermented sausage to control Shiga toxin-producing Escherichia coli (STEC). Meeting Abstract. STEC Coordinated Agricultural Project Annual Meeting.,May 28-30, 2013., Lincoln, Nebraska., Volume 1,Page 1. Technical Abstract: Shiga-toxin producing Escherichia coli (STEC) have been occasionally associated with causing illness due to under-processed and/or undercooked raw, further processed, and/or fermented meats. Regarding the latter, the United States Department of Agriculture (USDA) Food Safety and Inspection Service (FSIS) requires manufacturers of dry and semi-dry fermented sausage to follow 1 of 5 processing options to ensure the safety of their products. Two of these 5 options require manufacturers to reduce levels of STEC by a 5-log unit decrease and another of these options requires a 2-log unit decrease plus raw batter testing. Thus, the goal of this study was to evaluate the effectiveness of fermentation and cooking parameters (i.e., time and temperature) to deliver a 5-log or a 2-log reduction of STEC in a pepperoni-like, dry-fermented sausage. Coarse ground meat (25% beef, 75% pork and 30% fat, 70% lean) was purchased from a local vendor. The meat was mixed with a dry spice mix (3.69%), cure salt (3.69%), and a commercial starter culture (0.0188%; Pediococcus acidilactici) and inoculated with an 8-strain cocktail (ca. 7.0 log CFU per gram) comprised of single strains of serotype O157:H7, O104:H4, O26:H11, O45:H2, O103:H2, O111:H-, O121:H19, and O145:NM of STEC. Next, the batter was fine ground (3 16 inch grinding plate), stuffed into a 55-mm fibrous casing, and subsequently fermented at 96 deg F (35.6 deg C) and ca. 85% relative humidity to a final target pH of pH 4.6 or pH 5.2. After fermentation, the pepperoni-like sausages were cooked to target internal temperatures of 110 deg F (43.4 deg C), 120 deg F (48.9 deg C), and 130 deg F (54.4 deg C) and held for 0.5 to 24 h. In each of two trials, three chubs were analyzed at each sampling interval for each treatment tested. Regardless of the target endpoint pH, fermentation alone delivered a 0.74 to 1.58 log CFU per gram reduction in pathogen numbers. However, sausages fermented to pH 4.6 required less time to achieve appreciable reductions of the STEC cocktail than otherwise similar sausages that were fermented to pH 5.2. Fermentation to ca. pH 4.6 followed by post-fermentation cooking to 110, 120, or 130 deg F and holding for 0.5 to 8 h generated reductions of 1.36 to 5.72, 1.58 to 6.96, and 1.53 to 7.26 log CFU per gram, respectively. Likewise, fermentation to ca. pH 5.2 followed by post-fermentation cooking to 110, 120, or 130 deg F and holding for 1 to 10 h generated reductions of 1.16 to 6.75, 0.74 to 4.02, and 1.30 to 6.96 log CFU/g, respectively. Collectively, these data validated that fermentation to pH 4.6 or pH 5.2 delivered an approximate 5-log reduction in pathogen levels following cooking for 1.0 to 10 hours at 110 to 130 deg F. These data will be useful for manufacturers of dry-fermented sausages to achieve/validate the required reduction of STEC while producing a high-quality and wholesome product.