Influence of Bacillus polymyxa starter on chemical and microbial properties of Mahyaveh fermented sauce

Mahyave is a traditional Iranian fish sauce made from fish, salt, spices and water by the fermentation process. Although fish sauces have a high nutritional value, they contain biogenic amines as anti-nutritional compounds. This study aimed to investigate the effect of Bacillus polymyxa at a concentration of 108 cfu/ml on the chemical (pH, acidity, salt percentage, TVB-N, histamine and tyramine) and microbial (population of Enterobacteriaceae, Bacillus, Halophiles, Lactic acid bacteria and fungi in mahyaveh sauce. This study was administered in 4 experimental groups including control and treatment groups (containing bacteria) on 30 and 45 days. The results of microbial analysis showed that the population of Bacillus, Halophiles and fungi was significantly (p <0.05) decreased during fermentation. The colony population of Lactic acid bacteria and Enterobacteriaceae significantly increased during fermentation (p <0.05). Chemical analysis of the treated and control samples also showed that pH, salt percentage, histamine and tyramine content decreased in 45 days of fermentation, but acidity, TVB-N and protein concentration increased during 45 days of fermentation (p <0.05). Also Bacillus polymyxa reduced the amount of histamine and tyramine content in the product by effect on the fermentation process. The results show that addition of Bacillus polymyxa starter is an effective strategy for reducing biogenic amines in fermented fish sauces.