Evaluation of Antimicrobial Activities of Imported and Nigerian Fresh and Dried Pepper (Capsicum frutescens) Oleoresins against Selected Bacteria Isolates

Capsicum spp. oleoresins are natural antimicrobials used in the food industry. However, reliance on imports is unsustainable due to the increasing scarcity of foreign exchange in Nigeria. This study investigated the antimicrobial activities of Capsicum frutescens oleoresins in comparison with imported oleoresin. Ethanolic extracts of indigenous fresh and dried peppers were tested against Gram-positive [Enterococcus faecalis (FELA 097), Staphylococcus saprophyticus (S03), Staphylococcus saprophyticus, and Staphylococcus aureus] and Gram-negative [Enterobacter cloacae (FELA 064) and Escherichia coli (FELA O26)] bacterial isolates at different concentrations (50, 75, and 100%) and compared with imported oleoresin (IMPO). Dried C. frutescens var. longum oleoresin inhibited Gram-positive isolates at all concentrations, compared with C. frutescens var. baccatum, based on the zones of inhibition. The sensitivity of the isolates to different antibiotics indicated inhibition zones ranging from 12–21 mm for the extracts and 16–33 mm for the antibiotics. The antibacterial activity of C. frutescens oleoresins compared with that of imported oleoresin indicates their potential as preservatives and their possible application against foodborne pathogens.