Antibacterial activity of fat from black soldier fly (Hermetia illucens) larvae against antibiotic resistant Campylobacter spp. strains

In this study, the antibacterial effect of fats derived from black soldier fly larvae (BSFL) were evaluated against various antibiotic-resistant strains of Campylobacter jejuni and Campylobacter coli. BSFL fats with different free fatty acids (FFAs) contents were obtained based on the larvae’s processing conditions. Initially, antibiotic susceptibility testing revealed that all Campylobacter strains were resistant to at least one antibiotic, with two strains classified as multidrug-resistant. The antibacterial activity of the BSFL fats was directly correlated with their FFAs content. Fats obtained through freeze-drying and defatting via supercritical fluid extraction (SFE) exhibited the strongest antibacterial effects against Campylobacter spp., reducing bacterial growth by 4.1 to 5.6 log CFU/mL in C. jejuni and demonstrating bactericidal activity (reducing bacterial growth >6 log CFU/mL) against all C. coli strains. An analysis of the individual contributions of FFAs in BSFL fat revealed that lauric and linoleic acids were bactericidal (reducing bacterial growth >8 log CFU/mL), completely inhibiting the growth of C. jejuni and C. coli strains, while myristic, palmitic, and oleic acids showed no effect on Campylobacter growth. These findings suggest that BSFL fat, which has been shown to enhance broiler growth, could also serve as an effective strategy to combat Campylobacter spp. contamination in the food chain.

This research was funded by the Spanish National Plans of Aquaculture of the Ministry of Agriculture, Fisheries and Food, project ACUINSECT (Optimization of insect flours as sustainable ingredient for aquaculture feed), Grant PID2022-136238OB-I00 (ENTOMOTIVE) funded by MICIU/AEI/ 10.13039/501100011033 and by ERDF/EU, Grant AGL2017-89566-R (HELIFOOD) funded by MCIN/AEI/10.13039/501100011033 and by “ERDF A Way of Making Europe”.

Peer reviewed