Inhibition of Bacillus cereus by garlic (Allium sativum) essential oil during manufacture of white sufu, a traditional Chinese fermented soybean curd

Abstract

This study aimed to apply garlic essential oil (GEO) to control the Bacillus cereus content in white sufu, a traditional Chinese fermented soybean curd. The effect of GEO on the Bacillus cereus count, bacterial composition, and the metabolic changes during the fermentation process were investigated. After treatment with GEO, B. cereus was reduced from 5.26 to 4.58 log CFU/g in the finished product, meeting the Hong Kong Food Microbiological Guidelines. Three Lactic acid bacteria genera (Lactococcus, Weissella, and Leuconostoc), which showed a positive correlation with desirable metabolites, were present in greater numbers after the treatment. Hierarchical cluster analysis and principal component analysis showed that GEO caused no significant differences in polar metabolites (carbohydrates, organic acids, biogenic amines, nitrogen compounds, and free amino acids) and volatile compounds in the end-product. Thus, GEO appears to have great potential in sufu manufacture and preservation.