Studies on Growth Characteristics of Bacillus Strains Isolated from a Liquid Seasoning

Antimicrobial activity of fatty acid esters was examined on two Bacillus species with different germination rate in a chicken extract. The fatty acid esters with high hydrophobicity had strong antimicrobial activity toward B. cereus that showed high germination rate in the extract. Monoglycerol myristate was the most active toward B. cereus among fatty acid esters tested. On the other hand, monoesters of laurate had strong antimicrobial activity toward B. coagulans that showed low germination rate in the chicken extract. Monoglycerol monolaurate was the most active against B. coagulans among the fatty acid esters tested. The difference in the antimicrobial activity of fatty acid esters on these two Bacillus species seems to be attributed to the difference in the target and mechanism of the antimicrobial action. The antimicrobial activity of sugar esters toward B. coagulans was low as reported by other researchers. It was thought that the interaction between components in the extract and sugar esters decreased the concentration of the active esters in the extract. These results suggest that, to prolong the shelf life of meat extracts, it is important to identify Bacillus strains that cause putrefaction of the extract, and then select the most effective fatty acid ester to inhibit germination and growth of the target strain.