Investigating the Individual and Combined Effect of Essential Oils and Probiotics against Staphylococcus aureus

Background: The pathogenic bacteria present in food contribute to its spoilage and can lead to the development of diseases. Chemical preservatives exhibit toxicity and resistance problems, prompting the need for safer alternatives. Natural phytochemicals and probiotics are effective options, as essential oils and probiotics possess robust antibacterial characteristics. The objective of this study is to investigate the combined effects of probiotics (Lactobacillus plantarum, Lactobacillus casei, and Bifidobacterium bifidum) and essential oils derived from Murraya koenigii (curry patha) and Allium sativum (garlic) in inhibiting the growth of Staphylococcus aureus, a major foodborne pathogen. Methods: The study assessed the antibacterial effects of M. koenigii and A. sativum essential oils on S. aureus, both alone and in combination with probiotics (L. plantarum, L. casei, and B. bifidum). Antibacterial activity was measured at zero, 24, and 48 h using a culture plate method with serial dilution and pour plate technique. The Bliss Independent model was used to analyze interactions between control and treatments. Synergy factor and relative inhibition were determined using Python software to evaluate the combined effects of essential oils and probiotics. All treatments were performed in duplicate. Results: M. koenigii and A. sativum essential oils exhibit antibacterial activity against S. aureus, with M. koenigii demonstrating greater potency. Notably, their effectiveness in inhibiting bacterial cells is enhanced when combined with probiotics. In the control group, the colony forming unit/ml of S. aureus was 8.09±0.51, whereas in the presence of M. koenigii essential oil, it significantly reduced to 2±0.2. Conclusion: While both essential oils and probiotics have antibacterial effects on their own, using them together may require careful attention to ensure effectiveness.