Antimicrobial activity and applications of fermentates from lactic acid bacteria - a review

Abstract

Fermentates are complex mixtures containing inactivated or viable lactic acid bacteria (LAB) cells, growth metabolites, and culture medium compatible with different food applications, offering a cost-effective and practical alternative to LAB cell-free supernatants (CFS). Contrariwise to CFS, in fermentates, the bacteria in the growth medium are commonly inactivated to be used directly. Despite their commercial availability in the food industry, limited research has explored their antimicrobial potential. This review summarises the current knowledge regarding the antimicrobial activity of fermentates, both in vitro and in food applications. Furthermore, the paper discusses fermentates' physicochemical and sensory effects in foods. Studies indicate that commercial fermentates, applied at low concentrations (<2%), laboratory-produced fermentates at 10%, and sourdoughs at 20-30%, demonstrate effective antimicrobial properties. Notably, the reviewed literature suggests that fermentates minimally impact food products' physicochemical and sensory attributes. The antimicrobial activity of fermentates and their potential to replace chemical preservatives, together with their practical and cost-effective nature, contribute positively to sustainability in food production by reducing dependence on selective media and improving the quality of final products and their applicability in diverse food industries.