Title : Enterococci: a review of potential technological and functional properties
Abstract:
Enterococci, the most controversial group of lactic acid bacteria are human and animal intestinal commensals that can be found in almost every environment and place (water, plant, soil, and foods). With the development of modern classification techniques, some of the genera that were previously included in Lancefield's group D streptococci have been transferred to the new Enterococcus genus. Enterococci are neither GRAS (Generally Recognized As Safe) nor included in the QPS (Qualified Presumption of Safety) list. Although there are a significant number of strains belonging to different Enterococcus species, they are highly competitive due to their resistance to a wide pH and temperature range. Although enterococci are present in high numbers in some types of fermented cheese and sausages, they are not added intentionally as starter cultures. Some strains of Enterococcus faecium and Enterococcus faecalis are used as probiotics and are often administered in the form of pharmaceutical preparations to treat diarrhea, antibiotic-associated diarrhea or irritable bowel syndrome, lower cholesterol levels, or improve host immunity. It is desired that the strains planned to be used in foods should not have any virulence factors and should be clinically sensitive to some antibiotics. As a result of the studies, they are used as starters in fermented food production due to their biotechnological properties (enzymatic, proteolytic and lipolytic activities, citrate metabolism etc.) or as preservative cultures or probiotics in food biopreservation due to the antimicrobial bacteriocins called enterocins they produce, as well as they have different beneficial properties such as stimulating immunity. Enterocins can be used in different food products to increase their shelf life as they are heat stable and show activity in a wide pH range. Enterocins are as effective as they are safe for use in the food system because they are GRAS. E. faecium and E. faecalis are the predominant bacteriocin-producing Enterococcus species in food products. Living cells also provide anti-inflammatory activity, hypocholesterolemic effect, and use in the prevention/treatment of some diseases. These microorganisms are also important for the formation of bioactive peptides, especially from milk components, which provide new opportunities for the development of functional foods and nutraceuticals for human nutrition and health. Although there are many biotechnological advantages (eg. bacteriocin production, probiotic properties, usability in dairy technology), there is currently no consensus on whether enterococci pose a threat as foodborne pathogens.
