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

Summary Experiments were conducted to determine the maximum brine concentrations required to inhibit growth and toxin production of Clostridium botulinum Type A in heated, surface-ripened cheese designated as Type III cheese. This cheese is ripened primarily by bacteria. Data from three groups of trials are presented. With inocula of Type A spores, growth and toxin production occurred in cheese with brine concentrations up to 6.50%. In two groups with moderately ripened cheese at the normal pH, the maximum brine concentrations permitting growth and toxin production were in the same range in cheese with stabilizer as in similar cheese with no stabilizer. Cheese preparations with increased pH were poorer media for C. botulinum than was the cheese with normal pH. Major observations in comparable experiments with surface-ripened cheese designated Types I, II, and III are discussed.