Drone brood of Apis mellifera is often removed from the beehive to control the honeybee parasite Varroa destructor. Instead of discarding the drone brood, it could rather be used as a new food source for human nutrition. However, studies on microbiological hazards caused by edible insects are rare, especially in the case of drone brood. In this survey, microbial total viable cell counts and the most common foodborne bacteria were assessed in raw drone brood. Samples were taken from 24 beehives from four apiaries in Switzerland. The drone brood combs were harvested either by the beekeepers with their personal equipment or by the researchers with sterile equipment. No difference in the total viable cell counts was found between these two methods. All samples were free of Salmonella. Viable counts of Bacillus cereus, coagulase-positive staphylococci, Enterobacteriaceae and Escherichia coli were all below the detection limits of the recommended ISO reference methods. However, Listeria monocytogenes was detected in eight samples (all <10 cfu/g), which has not been reported in edible insects until now.
Honeybee navigation: following routes using polarized-light cues
