Inhibition of Bacillus cereus by lactic acid bacteria starter cultures in rice fermentation

Contamination by Bacillus cereus occasionally develops in Chinese fermented rice noodle products. To determine whether the growth of the pathogen might be inhibited by natural mixed lactic acid bacteria (LAB) starters in rice fermentation, B. cereus YSP-A3-2 was artificially added together with LAB starters by inoculation just before the fermentation process. The decrease of pH from 6.8 to 4.0 took place during the first 8 h and pH stayed under 4.0 during the rest of fermentation process in both of the concentrations of B. cereus (103 cfu/ml and 104 cfu/ml) tested, which decreased to 102 cfu/ml and 103 cfu/ml final concentration, respectively. The results suggest that the occasional contamination by B. cereus could be inhibited by the natural LAB starter, which was used in Chinese rice noodle factory by the back-slopping way