Abstract：Bucket worms are larva of longhorn beetles Apriona germari and A. swainsoni living in the trunk of Caesalpinia decapetala (Leguminosae). These insects are considered of high nutritional and medicinal value, and therefore widely consumed. The purpose of this study was to characterize the microflora of fresh edible bucket worms by the methods of high-throughput sequencing and traditional culture, and further evaluate the food safety based on relative abundance of Enterobacteriaceae, Saccharomycete, molds, and lactic acid bacteria (Lactobacillales) according to GB4789.1-2016 and ISO standards, and culture-dependent method was used to analyze thermoduric bacteria. The results showed that there were no significant differences between the microbial community compositions of 2 bucket worm species. The bacterial community of A. germari was mainly composed of Proteobacteria, Oxyphotobacteria and Bacteroides, while A. swainsoni was mainly composed of Proteobacteria, Firmicutes and Actinobacteria. Ascomycota and Basidiomycota were dominant fungal phyla in 2 bucket worm species, in which Ascomycetes were the absolutely dominant group. The analysis of safety-related indicators showed that relative abundance of Enterobacteriaceae in A. germari and A. swainsoni accounted for 60.28% and 39.82%, while Lactobacillus accounted for 1.24% and 3.65% respectively in bacteria; the molds accounted for 40.26% and 6.74% in fungal, while the yeast accounted for 59.74% and 93.26% respectively. Among yeast, 21 genera were found common in bucket worms, which were considered to be toxic or harmful to human beings (Homo sapien). In addition, 4 genera of potentially poisonous thermoduric bacteria including Staphylococcus, Streptomyces, Acinetobacter, and Pseudomonas were identified in 2 insect species, the colony number was significantly reduced after treatment at 50 ℃, 60 ℃ and 70 ℃, and almost inactivated completely at 80 ℃. Overall, the results of this study indicated that there were a variety of potential spoilage bacteria and food pathogens in the bucket worms, and the food safety risk could be eliminated or minimized through processing steps such as a shock heat treatment. The microbial safety evaluation based on high-throughput sequencing in present study could provide reference for hygiene criteria of edible insects.
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