Inhibitory Effects of Commercial and Enriched Green Tea Extracts on the Growth of Brochothrix thermosphacta, Pseudomonas putida and Escherichia coli

Abstract

The major catechin found in green tea, called epigallocatechin gallate (EGCG), have been reported to have antimicrobial properties. In this study, we examined in vitro the antimicrobial effects of a commercial green tea extract sold in a capsule form, and two prepared green tea extracts enriched in catechins against Brochothrix thermosphacta, Pseudomonsas putida and Escherichia coli which have been associated with meat spoilage. The antimicrobial activity of the different tea extracts was evaluated by Spot-On-Lawn and Well Diffusion assays and the Minimum Inhibitory Concentration (MIC) was also determined in Brain Heart Infusion broth. The three methods used showed an inhibition of Brochothrix thermosphacta, whereas the inhibition of Pseudomonas putida and Escherichia coli was only detected with the MIC assay. The determination of the MIC in broth culture appeared to be the most reliable method to determine the inhibitory activity of catechin compounds.