Inhibition of Salmonella typhimurium and Staphylococcus aureus by Butylated Hydroxyanisole and the Propyl Ester of p-Hydroxybenzoic Acid.

Inhibition of Salmonella typhimurium and Staphylococcus aureus in Trypticase Soy Broth by the propyl ester of p-hydroxybenzoic acid (propyl paraben, 0 to 500 ppm) and butylated hydroxyanisole (BHA, 0 to 400 ppm) alone and in combination was studied. A concentration of 200 ppm of BHA was bactericidal to S. aureus , while up to 400 ppm of BHA was only restrictive to the growth of S. typhimurium . A gradual decline in viable cell numbers of S. aureus was noted with addition of 500 ppm of propylparaben while an initial reduction of S. typhimurium and subsequent growth occurred at a level of 300 ppm of propylparaben. A combination of 50 ppm of BHA-propylparaben was needed to produce a gradual reduction in viable cells of S. aureus and 150 ppm of each additive caused S. typhimurium to exhibit an apparent decrease in cell numbers and then limited growth.