Factors Influencing Growth and Toxin Production in Cheese Inoculated with Spores of Clostridium Botulinum Types A and B. I. Studies with Surface-Ripened Cheese Type I

Abstract

Studies were conducted to determine the maximum brine concentrations that Clostridium botulinum Types A and B would tolerate before ceasing growth and toxin production in heated, surface-ripened cheese referred to as Type I. The flora of Type I cheese was not reported, but consists of bacteria and yeasts. In the 3 groups of trials involving moderately ripened cheese at its normal pH, cheese with pH raised, and cheese at its normal pH with added stabilizer, the maximum brine concentrations at which toxin was produced were similar for all groups. Growth and toxin production occurred in cheese with brine concentrations up to more than 8.0% when Type A spores were used; with Type B spores, the maximum brine concentrations tolerated were near 6.0%. Well-ripened cheese was a poorer medium than that moderately ripened.