title: Tea and soybean extracts in combination with milk fermentation inhibit growth and enterocyte adherence of selected foodborne pathogens.
abstract: This study examined the antibacterial and anti-adhesive properties of pure plant extracts (PPEs) of green tea (GT), black tea (BT) and soybean individually or in combination with milk. Fermented phenolic enriched-milk (fPEM) was prepared by combining PPEs with milk and fermented with lactic acid bacteria. Antimicrobial activity of extracts was evaluated by broth-dilution and agar diffusion assay. Anti-adhesive property of extracts was evaluated in Caco-2 cell model. Results from antibacterial tests showed that PPEs exhibited a dose-dependent growth inhibitory effect. Tea extracts were more effective in inhibiting Gram-positive bacteria while soybean extract exhibited similar effects against all pathogens tested. For fPEM, although total phenolic contents decreased compared with those in PPEs, growth inhibitory effect of fPEM containing tea extracts was greatly enhanced. All extracts showed significant inhibition against pathogen adhesion to Caco-2 cells. In particular, adhesion inhibition against Staphylococcus aureus and Listeria monocytogenes was >89% when fPEM extracts were applied.
authors.affiliation: Food and Nutritional Science - School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong.
authors.forename: Danyue
authors.initials: D
authors.lastname: Zhao
authors.affiliation: Food and Nutritional Science - School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong. Electronic address: npshah@hku.hk.
authors.forename: Nagendra P
authors.initials: NP
authors.lastname: Shah
mesh_terms: D000818:Animals; D018938:Caco-2 Cells / Q000737:chemistry*; D002417:Cattle; D005285:Fermentation; D005517:Foodborne Diseases / Q000382:microbiology*; D006801:Humans; D013025:Glycine max / Q000737:chemistry*; D013662:Tea / Q000737:chemistry*
chemical_list: D013662:Tea
keywords: Anti-adhesion; Antibacterial; Caco-2 cells; Milk fermentation; Phenolic extract