Aerosol Cans Research Articles

Effect of Gas Hydrate Formers on Microorganisms

VARIOUS BACTERIA, YEASTS, AND MOLDS IMPORTANT TO THE FOOD INDUSTRY WERE INCUBATED IN AEROSOL CANS CONTAINING A C BROTH AND ONE OF THE FOLLOWING THREE GAS HYDRATE FORMERS: propane, dichlorodifluoromethane (f-12), and 1,1-difluoro-1-chloroethane (f-142b). Most hydrate formers were tested at three concentrations: low (vapor state), intermediate (liquid state, low level), and high (liquid state, high level). Samples were continuously agitated for 48 hr at 21 +/- 3 C. Changes in numbers of microorganisms were determined by plate count. With hydrate formers in the vapor state, propane was more toxic to the microorganisms tested than either f-12 or f-142b. The most resistant organisms from these trials were then tested against f-12 or f-142b in the liquid state. Hydrate formers were far more toxic in the liquid state than in the vapor state. With the exception of sporulated cultures of Bacillus cereus, all microorganisms tested were greatly reduced in numbers when agitated for 48 hr at 21 C in the presence of f-12 or f-142b.

MICROBIOLOGY OF IMITATION AND FILLED DAIRY PRODUCTS AND THEIR COMPONENTS

Eighty-four imitation and filled milk products and 31 components used to fabricate such products were examined for total plate counts, coliform count, and the incidence of staphylococci and salmonellae.All purchased commercial products were free of staphylococci and salmonellae, but 4 of 84 (4.7%) contained coliforms. Products purchased in retail outlets as a powder had high total plate counts (average 107) more often than products purchased frozen, refrigerated or in aerosol cans (average 78).Fat or oil components had total plate counts of <10 per gram, whereas plate counts of powdered components ranged from <10 to 14,500 per gram. No components examined contained salmonellae, staphylococci, or coliforms.