Evaluation of Antimicrobial Activity of Buforin I and Nisin and the Synergistic Effect of Their Combination as a Novel Antimicrobial Preservative
ABSTRACT One of the most effective methods for increasing the antimicrobial activity of a substance is to combine it with one or more other antimicrobial agents. The aim of the present study was to evaluate the antimicrobial effect of buforin I and nisin alone and investigate the synergistic action of these compounds against the most important food spoilage microorganisms, including Bacillus subtilis, Staphylococcus epidermidis, Listeria innocua, Escherichia coli, Salmonella serovar Enteritidis, Aspergillus oryzae, Rhodotorula glutinis, and Geotrichum candidum. The results of MIC and MBC or minimum fungicidal concentration examinations showed that buforin I had higher antimicrobial activity than nisin on all microbial strains used in this study (P ≤ 0.5). E. coli was the most resistant to both antimicrobial agents, whereas L. innocua and S. epidermidis were the most sensitive to nisin and buforin I, respectively. The results of synergistic interaction between buforin I and nisin indicated that the combination of buforin I and nisin on B. subtilis, S. epidermidis, and A. oryzae showed a synergistic effect, whereas it had no effect on Salmonella serovar Enteritidis and G. candidum. The combination of buforin I and nisin showed a partial synergistic effect on L. innocua, E. coli, and R. glutinis. Assessment of viability of the microorganisms under the antimicrobial agents alone and in combination with each other at MICs and fraction inhibitory concentrations indicated that use of these antimicrobial agents in combination enhances antimicrobial activity at lower concentrations of both agents. The present study investigated the antimicrobial properties of buforin I against food spoilage microorganisms for the first time and suggests that its use alone or with nisin may provide a clear horizon for the application of antimicrobial peptides as natural preservatives. Thus, the combination of antimicrobial peptides and traditional antimicrobial food preservatives could be a promising option for the prevention of contamination, spoilage, and infestation of food and beverage products. HIGHLIGHTS