Behavior of Salmonella typhimurium DT104 during the manufacture and storage of pepperoni

Pepperoni batter (ca. 70% pork:30% beef) was prepared and subsequently inoculated with a six-strain cocktail (ca. 4.4×10 7 per gram batter) of Salmonella typhimurium DT104. After fermentation at 36°C and 92% relative humidity (RH) to ≤pH 4.8, counts of the pathogen decreased by about 1.3 log 10 units. An additional 1.6 log 10 unit decrease was observed following drying at 13°C and 65% RH to a moisture protein ratio (M/Pr) of 1.6:1. After storage of pepperoni sticks for 56 days under vacuum at 4 or 21°C, counts of the pathogen were about 4.6 and 6.6 log 10 units lower, respectively, compared with starting levels in the batter. These data establish that fermentation and drying result in about a 3.0 log 10 reduction in numbers of S typhimurium DT104 in pepperoni sticks and that storage of pepperoni sticks under vacuum at ambient temperature is more severe on the pathogen than refrigerated storage.