[Antimicrobial activity of phenolic antioxidants].

The antimicrobial activity of three antioxydants, butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA) and ethoxyquin (ETO) was studied. In vitro assays showed that when these antioxydants are added to the culture media at concentrations lower or equal to that used in nutrition, they inhibit or decrease the growth of certain microorganisms. BHT showed the most marked effect, affecting Gram-positive bacteria at a higher degree than the Gram-negative bacteria belonging to the family Enterobacteriaceae. Inactivation study of different bacterial species by BHT revealed differences in sensitivity among a single genus and between strains of the same species. The association of ETO with BHT results in an increase of the inhibitory activity. The increased sensitivity to BHT resulting from the osmotic shock of Escherichia coli cells suggests that the resistance to BHT of the Gram-negative bacteria belonging to the family Enterobacteriaceae might be due in part to the structure of their cell wall.