Susceptibility of Escherichia coli, Salmonella sp. and Clostridium perfringens to organic acids and monolaurin

The antimicrobial activity of fatty acids (C8 to C14), monolaurin, citric, succinic, fumaric, malic and lactic acids was determined in cultures of 2 strains of Escherichia coli, 3 strains of Salmonella sp. and 2 strains of Clostridium perfringens. Caprylic acid was the only acid inhibiting glucose utilization in all cultures. Strains CCM 3954 and CCM 4225 of E. coli were inhibited also by capric acid at 5 mg/mL. Strains CCM 4435T and CNCTC 5459 of C. perfringens were inhibited by fatty acids, oleic acid and one strain also by linoleic acid. Growth of C. perfringens was inhibited also by monoglyceride of lauric acid and by citric acid. The separation of inner and outer cell membranes was apparent in C. perfringens CCM 4435T treated with lauric acid at 1 mg/mL, or with its monoglyceride at 5 mg/mL. Medium-chain fatty acids were more efficient antimicrobials than the other, more polar, organic acids tested.