Genoa sausage and pepperoni inoculated with LACTACEL 75, a selected strain of Pediococcus sp., attained pH 5.0 after 12 and 11 h, respectively, at 35 C and after 48 and 40 h, respectively, at 21 C. LACTACEL 75 controlled the growth of S. aureus in the outer surface (0.5–1.0 cm, depth) of both Genoa sausage and pepperoni during the fermentation period to attain pH 5.0. In Genoa sausage, the population of S. aureus, in association with LACTACEL 75, was up to 1,000-fold lower than the minimal level associated with enterotoxin production. The generation times of S. aureus, in association with LACTACEL 75, (in Genoa sausage) were up to 15 times longer than those of the pathogen growing alone. In Genoa sausage at 21 C, LACTACEL 75 was bactericidal, causing a 42% decrease in the population of S. aureus. LACTACEL 75, in combination with BHA and BHT, brought about a 67% inhibition of growth of S. aureus in Genoa sausage, as compared to the growth of the pathogen in the absence of the starter culture and the phenolic-type antioxidants. In pepperoni at 35 C, LACTACEL 75 prevented a >2 log increase in the population of S. aureus.
1Present address: Division of Agriculture, Arizona State University, Tempe, AZ 85287.