Antimicrobial activity of pomegranate (Punica granatum L.) fruit peels

Food-borne diseases such as listeriosis and diseases caused by the emergence of multi-drug resistant pathogens (e.g. Staphylococcus aureus) are globally recognized as environmental hazards to the food supply and human health. Natural inhibitors for pathogenic microorganisms have been explored in many plants. The antimicrobial activity against some food-borne pathogens by various extracts from pomegranate fruit peels was evaluated using both in vitro (agar diffusion) and in situ (food) methods. The 80% methanolic extract of peels (WME) was a potent inhibitor for Listeria monocytogenes, S. aureus, Escherichia coli and Yersinia enterocolitica. The minimum inhibitory concentration (MIC) of WME against Salmonella enteritidis was the highest (4 mg/ml). WME afforded > 1 log10 reduction of L. monocytogenes in food (fish) during storage at 4 °C. Phytochemical analyses revealed the presence of active inhibitors in peels, including phenolics and flavonoids. The activity of WME was related to its higher content (262.5 mg/g) of total phenolics.