Nutrient broth inoculated with Salmonella typhimurium was dispensed into epoxy-lined aerosol cans. Twenty-five volatile compounds were then individually added to the cans to yield or non-volatile compounds were then individually added to the cans to yield final concentrations of 1, 10, 100, and 1000 ppm of each compound. Compounds tested included fatty acids (formic, acetic, butyric, hexanoic, octanoic and decanoic), aldehydes (formaldehyde, acetaldehyde, propionaldehyde, and glyoxal), ketones (acetone, 2-butanone, and diacetyl), amines (propyl and hexylamine), alcohols (furfurol and methanol), sulfur compounds (methylsulfide, methylsulfone, methanethiol, and ethanethiol), acetonitrile, chloroform, ether, and ethylenedichloride. Bacteria were enumerated at intervals during incubation at 37 C.
Shorter chain fatty acids generally inhibited S. typhimurium more than did longer chain acids. At 10 ppm formic acid was most effective of those tested and at 1 ppm fatty acids were generally not inhibitory. Formaldehyde and glyoxal were more inhibitory than acetaldehyde and propionaldehyde. Diacetyl was most effective of the three ketones tested. Low concentrations of acetone or 2-butaoone sometimes enhanced growth of S. typhimurium. Acetonitrile at all concentrations tested significantly inhibited S. typhimurium during the terminal stages of incubation. Ether (10 ppm), chloroform (10 ppm), ethylenedichloride (100 ppm), and methylsulfone (100 ppm) generally caused significant reduction in growth of S. typhimurium. Ethanethiol was more detrimental to growth of S. typhimurium than were methylsulfide or methanethiol; amines were more inhibitory than alcohols.
