Background and Aim: Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus cereus can cause food poisoning and digestive disorders in human beings. Propolis has been known as an antimicrobial agent against bacteria. The aim of this study was to determine the in-vitro antimicrobial activity of propolis extract on bacterial strains.

Material and Methods: In this study, we evaluated antibacterial effects of propolis alcoholic extract on Staphylococcus aureus (ptcc1112), Bacillus cereus (ptcc1247) and Pseudomonas aeruginosa (ptcc1707) for three times, by means of paper disc method (determination of inhibition zone diameter) and broth dilution, determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Using SPSS software, statistical analysis was performed by DUNCAN test.

Results: The results showed that the antibacterial activity and inhibition diameters for Staphylococcus aureus, Bacillus cereus and Pseudomonas aeruginosa (in a propolis extract concentration of 5.25 mg / ml) were respectively 18.66±0.58, 18, 14.33±0.58, respectively. S. Aureus had the highest sensitivity and Pseudomonas aeruginosa showed the highest resistance to alcoholic extract of propolis. The minimum inhibitory concentrations (MIC) for Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus cereus were 0.656, 0.656 and 2.62 mg/ ml respectively and the lethal concentrations (MBC) for Clostridium sporogenes, Escherichia coli and Staphylococcus aureus, were 0.656, 0.656 and 2.62 mg/ ml respectively.

Conclusion: The alcoholic extract of propolis had inhibitory and antibacterial effects on Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus cereus. Considering organoleptic effects of propolis extract, it can be used as a preservative in food.

Keywords: Propolis, Inhibition, Anti-bacteria, Staphylococcus aureus, Bacillus cereus, Pseudomonas aeruginosa.

Received: Dec 26, 2015      Accepted: Jan 21, 2016