Lethal effect of butylated hydroxyanisole as related to bacterial fatty acid composition.

Bacillus cereus, Clostridium perfringens, Staphylococcus aureus, Pseudomonas fluorescens, Pseudomonas fragi, Escherichia coli, and Salmonella "anatum" were challenged with butylated hydroxyanisole (BHA). Susceptibility was measured as the concentration of BHA required to cause a 90% reduction in bacterial survivors. Staphylococcus aureus LP and P. fragi were two of the most resistant species examined; C. perfringens and P. fluorescens were the most susceptible. Gram stain reaction was found not to be a strict indicator of bacterial susceptibility to BHA. There was no obvious relationship between individual fatty acids and susceptibility. The ratio of saturated to unsaturated fatty acids in the total lipid fraction of only the gram-positive species was related to susceptibility. The ratios of saturated to unsaturated fatty acids of other fractions were not related to susceptibility.