An evaluation of the antimicrobial effect of Hermetia Illucens oil on Staphylococcus aureus, Escherichia coli and Clostridium perfringens

This thesis investigates the antimicrobial potential of Hermetia illucens (HI) oil against Staphylococcus aureus (SA), Escherichia coli (EC), and Clostridium perfringens (CP), all significant in livestock and food safety. The antimicrobial properties of HI oil, largely attributed to its high lauric acid content, were tested by incubating the above-mentioned bacteria species in various broths: growth-optimized broths, a control broth with palm oil, and broths containing 2% and 50% HI oil. The broths, each tested in triplicate for each bacterium, were incubated for 48 hours at 37.0 ± 1 °C in a shaking incubator to ensure movement of the broth/oil mixtures. At various time points during the incubation, diluted broth samples were spread onto Petri plates to determine the bacterial concentration at each time point, per each broth type. Results were read after 24 hours of incubation (without movement) at 37.2± 1 °C. Colony-forming units (CFU) on each plate represented the data collected and analysed to create growth curves. ANOVA was conducted to identify potential growth differences, followed by Tukey’s post hoc test for pairwise comparisons; significance was set at P ≤ 0.05. Results demonstrated that the 50% HI oil significantly inhibited SA growth within 8 hours, slowed EC growth, while it did not affect CP growth. The 2% HI oil showed inhibitory effects on SA and a bacteriostatic effect on EC. These findings suggest the potential of HI oil as a sustainable alternative to antibiotics in animal farming, benefiting both animal welfare and animal-based food production by controlling the spread of pathogens.