Inhibition of bacteria by some volatile and non-volatile compounds associated with milk

TLDR: In this article, a broth inoculated with Streptococcus thermophilus was dispensed into epoxy-lined aerosol cans and five volatile or non-volatile compounds likely to be present in milk were added individually to cans to attain concentrations in broth of 1, 10, 100, and 1000 ppm of each compound.

Abstract: APT broth inoculated with Streptococcus thermophilus was dispensed into epoxy-lined aerosol cans. Twenty five volatile or non-volatile compounds likely to be present in milk were added individually to cans to attain concentrations in broth of 1, 10, 100, and 1000 ppm of each compound. Compounds used included formic, acetic, butyric, hexanoic, octanoic, and decanoic acid; formaldehyde; acetaldehyde; propionaldehyde; glyoxal; acetone; 2-butanone; diacetyl; propyl- and hexylamine; furfurol; methanol; methylsulfide; methylsulfone; methanethiol; ethanethiol; acetonitrile; chloroform; ether; and ethylenedichloride. Bacteria were enumerated at intervals during incubation at 37 C. Of the six fatty acids tested, decanoic acid was most and hexanoic acid was least inhibitory to S. thermophilus. At 1000 ppm all fatty acids tested always significantly inhibited S. thermophilus. Formaldehyde was more inhibitory to the bacterium than were acetaldehyde, propionaldehyde, or glyoxal. Of the ketones tested, diacetyl was mos...