Monitoring the Change in Bacterial Community during Traditional Fermentation of Broad Bean Sauce

Abstract:

Dynamic change of microorganismsin the process oftraditional fermentation of broad bean saucehas an important effecton the maturity，flavor formation and food safety of the product. To quantitatively analyze the dynamic changes of bacterial species during traditionalsunshine- exposedfermentation of broad bean sauce，strain-specific Rep-PCR fingerprinttechnology was adopted. The dominant strains were identified. Results indicated that during the traditional fermentation process，the total number of aerobic bacteria remained at a higher level（107～108 CFU/g），mainly including Bacillus subtilis，B.amyloliquefaciens and B.methylotrophicus. The total number of facultative anaerobe was 103～104 CFU/g and composed of B. cereus. At the early stage of the fermentation，B. subtiliswas the dominant bacteria and accounted for more than 80%，while the content of B.amyloliquefaciens and B.methylotrophicus increasedat the later period of fermentation. Therefore，Bacilli played a major role in the traditional fermentation of the broad bean sauce. The identified B. cereuswas related to the open fermentation mode. By comparison to aerobic bacteria，The number of B. cereuswaskept at a low level，which guarantees the safety of the traditionally fermented food.