Minimum Inhibitory Concentrations of Phenolic Extracts and Resistant Starch for Clostridium perfringens: In vitro Study

BACKGROUND: Clostridium perfringens, as a bacterial agent causing foodborne illnesses, is of great importance in the food industry. On the other hand, the increasing concern of antibiotic resistance is forcing humans to find an alternative to antibiotics. OBJECTIVES: This study aimed to evaluate the antimicrobial activity of the extracts of grape pomace, pistachio peel, and pomegranate pomace against Clostridium perfringens (C. perfringens) in the presence or absence of resistant starch (RS) as a prebiotic. METHODS: The RS (Fibersol-2) was purchased, and the extracts of grape pomace, pistachio peel, and pomegranate pomace were prepared. The total phenolic content and tannin of extracts were determined by Folin-Ciocalteu and standard tannic acid method, respectively. The antimicrobial activity of the extract with or without RS was evaluated using the minimum inhibitory concentration (MIC) against C. perfringens. RESULTS: Our findings showed that 100 ppm of pistachio peel extract could act as an inhibition factor against the growth of C. perfringens. The RS alone was not able to prevent C. perfringens growth. In contrast, 400 ppm dilution of RS+grape pomace extract could restrain C. perfringens growth. In contrast, the pomegranate pomace extract with and without RS could not inhibit its growth. On the other hand, the RS±pistachio peel extract could not prevent C. perfringens growth, in comparison with other treatments. CONCLUSIONS: We concluded that grape pomace extract, both with and without RS, effectively prevented C. perfringens growth.