Interactions Between Black Soldier Fly Larvae and Foodborne Pathogens: Implications for Growth, Welfare, and Bioconversion Efficiency

Abstract

This study investigates the interactions between black soldier fly (BSF) larvae (Hermetia illucens) and foodborne pathogens, specifically Salmonella spp and Escherichia coli (E. coli), to assess their impact on larval growth, welfare, and bioconversion efficiency. BSF larvae were reared on substrates inoculated with varying combinations of these pathogens and compared to a control group. Results indicated that larvae exposed to individual treatments of Salmonella spp or E. coli exhibited significantly slower growth rates, achieving only about half the weight of control larvae by Day 9. Notably, Salmonella spp exposure shortened the larval stage while prolonging the prepupal stage, suggesting metabolic stress. In contrast, the combination of both pathogens enhanced bioconversion rates, indicating complex microbial interactions that may benefit waste processing. The dynamics of pathogen persistence revealed that E. coli remained detectable in substrates for up to nine days, while Salmonella spp was only present for three days, highlighting the larvae's potential to mitigate pathogen levels in organic waste. Despite the resilience of BSF larvae to varying microbial loads, exposure to these pathogens negatively affected adult emergence rates, raising concerns about population sustainability and overall health. These findings underscore the importance of optimizing rearing conditions and implementing stringent quality control measures to minimize pathogen risks in BSF production systems.