ANTIMICROBIAL ACTIVITY OF PU‐ERH TEA EXTRACTS IN VITRO AND ITS EFFECTS ON THE PRESERVATION OF COOLED MUTTON

ABSTRACT The inhibitory effect of the extract of pu‐erh tea (PETs) against six strains by paper‐diffusion methods and the characterization of the mutton treated with different concentrations of the PETs during storage at 7 ± 1C were evaluated in this article. The results showed PETs could significantly inhibit the growth of Listeria monocytogenes, Salmonella typhimurium, Streptococcicosis faecalis, Escherichia coli and Bacillus anthraci, and their minimum inhibitory concentration were 0.07, 0.18, 0.50, 0.42 and 0.48 mg/mL, respectively. PETs showed weak inhibition for S. aureus. The cooled mutton treated with PETs resulted in suppression in the increase of total volatile base nitrogen and thiobarbituric acid reactive substance, inhibition of Enterobacteriaceae and Pseudomonas growth. The cooled mutton treated with 2% PETs showed highest color and overall acceptability. These results suggest the high potential in using PETs as a means of enhancing freshness and quality in cooled meats. PRACTICAL APPLICATIONS Antimicrobial activities of microbial fermented tea are much less known than its health beneficial properties. Pu‐erh tea is consumed by people as a daily healthy drink all over the world, extracts of pu‐erh tea may be safe to use in food systems to extend the shelf life. With the trend of increasing use of natural and biological preservatives in food products, natural antimicrobial agents from pu‐erh tea may offer an innovative and interesting measure for such applications.