Potential of Antimicrobial Peptide-Overexpressed Tenebrio molitor Larvae Extract as a Natural Preservative for Korean Traditional Sauces

Simple Summary In this study, the antimicrobial activity and stability of immunized Tenebrio molitor larvae extract (iTME) were confirmed, and the antibacterial activity was observed in Korean traditional soy sauce. As a result, iTME showed antibacterial activity against food poisoning bacteria and harmful fungi. It had stability in various pH, temperature, and salinity ranges, and antibacterial activity in Korean traditional soy sauce inoculated with food poisoning bacteria. Therefore, iTME has the potential as a natural preservative with stable antimicrobial activity. Here, we aimed to produce a natural food preservative using a crude extract from edible, immunized Tenebrio molitor larvae (iTME), injected with edible bacteria using an edible solvent. Results showed that iTME had concentration-dependent inhibitory activity against food-poisoning bacteria Escherichia coli, Bacillus cereus, and Staphylococcus aureus, as well as against harmful fungi Aspergillus flavus, Aspergillus parasiticus, and Pichia anomala. Moreover, iTME showed antimicrobial activity against beneficial microorganisms Bacillus subtilis and Aspergillus oryzae, but not Lactobacillus acidophilus. Furthermore, the minimum inhibitory concentration of iTME against E. coli, B. cereus, and S. aureus was 1 mg/mL, and iTME did not lose its inhibitory activity when treated at varying temperature, pH, and salinity. In addition, the antibacterial activity was lost after reacting the iTME with trypsin and chymotrypsin. The addition of iTME to Ganjang inoculated with harmful bacteria inhibited bacterial growth. Therefore, we propose that iTME can be used as a safe natural preservative to prolong food shelf life by inhibiting the growth of food-poisoning bacteria in a variety of foods, including traditional sauces.