Effect of the Licorice (Glycyrrhiza glabra) Ethanol Extract on Growth of Bacillus cereus at the Meju Producing Stage

The effects of Licorice ethanol extracts, which are natural antibiotic active materials, against the growth of Bacillus cereus and of Licorice extracts on soybean paste were investigated. Licorice extracts had strong effects against the growth of B. cereus when added at a concentration of 0.05% to the nutrient broth. Licorice extracts were added at the Meju producing stage to investigate its effects against B. cereus and ripening soybean paste. In these experiments, 96% of B. cereus was eliminated in the soybean paste containing Licorice extract concentration of 0.05% compared with soybean paste without Licorice extract. In addition, no B. cereus was detected in soybean paste when Licorice extract at a concentration of 0.4% was added. The amino nitrogen content in samples containing the added Licorice extracts was not much different from the control; thus, the Licorice extract does not appear to affect ripening soybean paste. Consequently, the addition of Licorice extracts to soybean paste holds promise for use as an effective method to eliminate B. cereus from soybean paste.