Antibacterial effect of Bunium persicum, Eucalyptus globules, and Allium ampeloprasum extracts on STEC and MRSA in commercial barley soup

   Background and aims: The antibacterial potency of Bunium persicum (BP), Eucalyptus globules (EG), and Allium ampeloprasum Var. Iranicum (AAI) hydroalcoholic extracts were evaluated against multidrug resistance (MDR) Escherichia coli and Staphylococcus aureus in vitro and in commercial barley soup during refrigerated and environmental storage. Methods: In an experimental study, the BP, EG, and AAI extracts were prepared and their antibacterial activities were evaluated against MDR E. coli and S. aureus by micro dilution and disc diffusion methods. Then, the effects of BP and EG extracts were examined on microbial quality of commercial barley soup at ۴±۱°C and ۲۲±۲ °C in zero, ۱, ۳, ۶, and ۹ days in different concentrations (BP ۱ and ۲%; EG ۱ and ۲%). Results: Two tested bacterial strains were susceptible to the BP and EG extracts and did not show susceptibility to the AAI extract. The count number of the bacteria in soup were was significantly reduced by the addition of the extracts. The lowest population of the S. aureus was determined in the samples treated with the EG at ۱ and ۲% during refrigerated and environmental storage. E. coli was suppressed by ۱.۵۴ and ۳.۴ log CFU/mL at ۱ and ۲ % BP and ۱.۵۷ and ۳.۵ log CFU/mL at ۱ and ۲ % EG, respectively, compared with the control on day ۹ during environmental storage Conclusion: According to our results, BP and EG extracts can be used as natural antimicrobial preservatives in commercial barley soup.

Keywords:

Bunium persicum , Eucalyptus globules , Allium ampeloprasum , drug resistant , soup