Identification of the bacterial microflora of fresh edible yellow mealworm larvae (Tenebrio molitor L.)

The edible insects are consumed as an alternative animal protein source by most Asian countries. Since there is a limited evidence for their safety particularly from microbiological aspects, an attempt was made to assess the microbial population of Tenebrio molitor L. samples in laboratory conditions. Primary stocks were purchased from a local market, in Sari- a city in north of Iran. Microbial samples were prepared from both body surfaces and guts of insect. Samples were individually and cultured on nutrient agar (NA), incubated at taken 270C for 24-72h. Distinguished colonies were isolated and purified. Based on phenotypic characteristics, hypersensitive response (HR) on geranium leaves, as well as 16S rRNA gene sequencing analysis, the isolates were categorized into two groups. The pathogenic isolates were identified as Bacillus cereus, Staphylococcus sp, Pseudomonas aeruginosa, Enterobacter asburiae, Bacillus firmus and Serratia marcescens. Whereas, the nonpathogenic bacteria were assigned as Enterobacter cloacae and Bacillus thuringiensis. Undoubtedly, the presence of pathogenic microbes in the microflora of mealworm larvae by direct and indirect consumption of insect may pose a threat to human and animal health. These findings suggest an implementation of certain processing methods in order to decrease or eradicate risks of microbial contamination of diets using natural insects.