Microbial and chemical analysis of independently produced batches of Tenebrio molitor larval powder

Due to the continuous growth of the world population, European countries have recently declared Tenebrio molitor (mealworm) powder safe as an alternative protein source for humans. Despite the positive aspects raised about mealworm powder, its marketability faces challenges due to some safety concerns. There is a lack of profound insight into the microbial safety, chemical reactions during storage and shelf life of Tenebrio molitor larvae intended for human consumption in Zimbabwe. Mealworm powder can be contaminated by components such as heavy metals, mycotoxins and pesticides which usually occur during feeding and storage of finished products. The aim of this study was to investigate the presence of bacteria, fungi and aflatoxins in two independently produced batches of Tenebrio molitor larval powder quantitatively to confirm its safety. Culture dependent analyses were performed to determine the presence of fungi and bacteria. The potential spoilage bacteria and food pathogens found were then enumerated and characterised. Thin layer chromatography was used to analyse aflatoxins in the mealworm powder. Microbial analysis revealed the presence of Aspergillus species, Rhizopus species, Rhodotorula species, Staphylococcus species, Enterobacteriaceae and lactic acid bacteria (LAB) in the two independently produced batches of Tenebrio molitor larval powder. However, the microorganisms present were below levels that cause food poisoning. Aflatoxin analysis showed the presence of aflatoxin B1 at a lower value of 12 parts per billion in the sample compared to the FDA standards of 20 parts per billion. In conclusion, based on this study, Tenebrio molitor larval powder may be safe for human consumption as the microbial and aflatoxin concentrations were below poisonous levels.