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. 4.4×107 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 log10 units. An additional 1.6 log10 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 log10 units lower, respectively, compared with starting levels in the batter. These data establish that fermentation and drying result in about a 3.0 log10 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.