Antimicrobial activity of fermented industrial soybean waste extracts against food spoilers and foodborne pathogens

The spoilage of food caused by the microorganism affects food safety and consider as important problem in food industry. Control of microbial growth with chemical preservatives have negative effect to consumers' health. Bio-preservatives, for example extract of fermented soybean meal, are improved antimicrobial activity by fermentation process. Therefore, this study aimed to study the antimicrobial properties of seven fermented soybean meal extracts including B001, B010G, LY4/9, LY4/11, LY7/6, LY9/5, and PB5/6 by agar well and diffusion assays against the following microorganisms: Bacillus cereus TISTR747, Escherichia coli TISTR117, Micrococcus luteus TISTR1918, Pseudomonas aeruginosa TISTR1287, Salmonella enterica TISTR1469, Staphylococcus aureus TISTR746, Vibrio parahaemolyticus, Saccharomyces cerevisiae wild-type BY4742 and the mutant strain ∆pdr5. Bactericidal activity was observed in the PB5/6 and LY7/6 extracts against E. coli TISTR117 and M. luteus TISTR1918, respectively. The LY7/6 extract inhibited S. enterica TISTR1469 and V. parahaemolyticus at concentration 100 mg/ml with bacteriostatic activity. In summary, the fermented soybean meal extracts LY7/6 and PB5/6 were effective inhibit food spoilage microorganisms suggesting potential application as bio-preservatives for foods.