Antibacterial efficacy of Enterococcus microencapsulated bacteriocin on Listeria monocytogenes, Listeria innocua and Listeria ivanovi

This study focused on the microencapsulation of enterocin from Enterococcus durans (E. durans MF5) in whey powder (WP) using a spray-drying technique followed by the evaluation of how complexation can preserve the enterocin structure and antimicrobial activity against food-borne pathogens. Crude enterocin samples (1 and 5%) were microencapsulated in 10% WP. The antimicrobial activity of unencapsulated (crude) enterocin and microencapsulated enterocin was tested against the target bacteria Salmonella Typhimurium, Escherichia coli, Listeria monocytogenes, Listeria innocua, and Listeria ivanovi. The microencapsulation yields were 31.66% and 34.16% for concentrations of 1 and 5% enterocin, respectively. There was no significant difference between these concentrations. Microencapsulated enterocin was efficient for up to 12 h of cocultivation with Listeria sp., and the concentration required to inhibit the growth of target bacteria presented values of 6400 AU/mL (arbitrary unit). Microencapsulated enterocin demonstrated enhanced efficacy against Listeria species and E. coli when compared with crude enterocin (p < 0.05). Fourier transform-infrared spectroscopy and differential scanning calorimetry results confirmed the presence of enterocin in the microparticles. Scanning electron microscopy showed cell damage of the target bacteria. The results showed that complexation with WP preserved enterocin antimicrobial activity during spray-drying, indicating its potential use as a food preservative.