Potential and Constraints of Use of Indigenous Enterococci in Dairy Industry

Enterococci form part of the lactic acid bacteria of importance in foods. They are nonstarter lactic acid bacteria in a variety of autochthonous cheeses in Southern Europe. Some indigenous strains of E. faecium have interesting technological properties for cheese manufacture, together with good safety characteristics. They are important in the development of sensory characteristics during ripening of many cheeses and have been used as components of cheese starter cultures. Enterococci are also used as human probiotics. Some enterococci of dairy origin produce bacteriocins (enterocins), which have an inhibitory effect against food spoilage and pathogenic bacteria. The characteristics of enterocins have led to the proposed use of enterococci as adjunct starter or protective cultures in cheeses. Otherwise, enterococci as opportunistic pathogens which cause diseases of humans and animals and carriers are genes of resistance on pathogenic bacteria. Virulence factors of enterococci are the cytolysin (hemolysin), gelatinase, creation of peroxide, surface proteins for aggregation, surface proteins for adhesion, a surface binding collagen protein, capsule, hyaluronidase. Because of multiple resistance to antibiotics, mortality from nosocomial infections caused by enterococci is about 61%. Enterococci very easily acquire resistance to antibiotics by mutation or by receiving resistance genes from other microorganisms located on chromosome, transferable plasmids and transposons. It can be concluded that prior to the use of enterococci as a starter culture, an adjunct of cultures or probiotics, it is necessary to fully investigate the virulence and resistance of enterococci on antibiotics for the purpose of health security. On the other hand, in order to prevent the occurrence of vancomicin resistant enterococci in the gastrointestinal tract of humans and animals and dissemination in the environment and food, it is necessary to carry out strict control of the use of antibiotics.