Investigating the antimicrobial properties of Lactobacillus casei and white tea (Camellia sinensis) extract on Escherichia coli and Listeria monocytogenes
Subject Areas : Journal of Quality and Durability of Agricultural Products and Food StuffsAfsaneh Vafa 1 , Maryam Ghane 2 , Laleh Babaeekhou 3
1 - MSC, Department of Biology, Islamshahr Branch, Islamic Azad University, Islamshahr, Iran
2 - Associate Professor, Department of Biology, Islamshahr Branch, Islamic Azad University, Islamshahr, Iran
3 - Associate Professor, Department of Biology, Islamshahr Branch, Islamic Azad University, Islamshahr, Iran
Keywords: Lactobacillus casei, antimicrobial properties, white tea, Escherichia coli, Listeria monocytogenes,
Abstract :
The antimicrobial effects of tea have been proven on many microorganisms. Probiotics are microbial food supplements that have beneficial effects on human health. This study was conducted to investigate the antimicrobial effect of Lactobacillus casei and white tea (Camellia sinensis) extract on Escherichia coli and Listeria monocytogenes. For this purpose, white tea extract was prepared and its antimicrobial properties against E. coli and L. monocytogenes were evaluated by broth dilution and disk diffusion methods. L. casei was also cultured and after preparing the supernatant, the antimicrobial properties of the supernatant and its synergistic effect with white tea extract were investigated by well diffusion method. The results showed significant antimicrobial activity of white tea extract with inhibition zones of 15±0.4 and 18±0.6 mm for E. coli and L. monocytogenes, respectively. The minimum inhibitory and bactericidal concentrations of white tea extract for L. monocytogenes were 6.5 and 12.5 and for E. coli were 12.5 and 25 mg/ml. The combination of white tea extract and L. casei supernatant produced inhibitory properties with an inhibition zone of 23±0.6 and 20±0.2 mm for
E. coli and L. monocytogenes, respectively. The results showed that white tea has significant antimicrobial properties and L. casei supernatant can significantly enhance its antimicrobial activity. This combination can be considered as a promising candidate as a food additive to combat foodborne pathogenic bacteria
