Antimicrobial peptides from the edible insect Musca domestica and their preservation effect on chilled pork

Antimicrobial compounds from natural sources are a promising alternative to address the consumer demand of food without chemical additives. In this study, antimicrobial peptides (AMPs) from infected Musca domestica pupae (Md-AMPs) bred under clean conditions were isolated and prepared on a large scale. In these Md-AMPs, seven AMPs families were identified by liquid chromatography-tandem mass spectrometry. Md-AMPs at concentrations from 0.4 to 0.8 mg/ml exhibited antibacterial activity and showed negligible hemolytic activity against human erythrocytes. Md-AMPs increased bacterial membrane permeability of four tested strains, resulting in the leakage of phosphorus-containing materials and Ca2+. Md-AMPs bound plasmid DNA and inhibited its migration in a concentration-dependent manner. Treatment with Md-AMPs alone or in combination with nisin, and ethylenediaminetetraacetic acid was efficient in inhibiting bacterial growth in chilled pork and extended the shelf life up to 6 days. Practical applications Insects have been widely used as foods and many biofunctional components are found in insects. In this work, we isolated and prepared AMPs from M. domestica, and its antibacterial activity, hemolytic activity, and mechanism of action were investigated. Trials in real food products showed that Md-AMPs alone or a combination of three natural antimicrobials could remarkably inhibit bacterial growth in chilled pork. These results suggest that Md-AMPs can be used as food preservatives.