Impact of residual streams on antimicrobial resistance in circular food systems using black soldier fly larvae

This study investigates the microbial and antimicrobial resistance gene composition of black soldier fly larvae when valorising various residual streams in view of circular food production systems. By assessing the microbial composition of larvae reared on different residual streams, a better overview can be created to optimize waste valorisation processes and address microbial safety and antimicrobial resistance concerns effectively. The results revealed that Pseudomonadota was the most relative abundant phylum across all starting substrates, with Bacillota showing higher relative abundance in larvae compared to frass. At the species level, Providencia rettgeri and Enterococcus wangshanyuanii were among the most abundant across treatments. Alpha-diversity measures showed no significant differences, while beta-diversity indicated significant effects of matrix, treatment, and their interaction. When focusing on antimicrobial resistance (AMR) genes, Tetracycline resistance genes were prevalent, with the highest number observed in frass from black soldier fly larvae grown on sludge from a dairy processing plant. Integration of microbiota taxonomic data with AMR gene profiles highlighted Acinetobacter colistiniresistens and Pseudomonas aeruginosa as key bacteria with multiple AMR gene clusters. These findings underscore the potential of black soldier fly larvae in waste valorisation, while highlighting the need for further research to address microbial safety and antimicrobial resistance concerns.