Effectiveness of fatty acids and their monoglycerides against gram-negative pathogens

The effectiveness of lauric, myristic and palmitic acids and their monoglycerides against Escherichia coli O157:H7, Yersinia enterocolitica and Salmonella sp. A total of 20 ppm of myristic and palmitic acids and their monolgycerides showed a promising bioactivity (60-80%) against E. coli O157:H7 within 10-24 h; 50 ppm of monolaurin inhibited Y. enterocolitica and E. coli O157:H7 by > 90% of control for 96 h; otherwise, 40 ppm of monolaurin and 30-50 ppm of lauric acid reduced Y. enterocolitica growth by > 65% of control. The effect of lauric acid and its monoglyceride against Salmonella spp. was moderate (inhibition of approximately 30%). The results of this paper suggested some interesting ideas: the same compound could exert an inhibition or a stimulation of microbial growth; moreover, the studied compounds seemed to act in a reversible manner, as the inhibition of micro-organism was quite strong within the first 10-24 h and decreased for a prolonged incubation.