Understanding the enterococci bacteria family - mostly found in non-heat treated foods - formed the prime objective of a recent European funded project.
Enterococci present in foods may contribute to the flavour or act as probiotics, but they may also be pathogenic. Found in particular in cheeses produced from non-pasteurised milk - such as Feta, Roquefort or Montasio - they contribute to their ripening and taste development. They also play a role in the flavour development of foods, such as sausages or olives. Some strains may also be used in starter cultures to improve sensory properties, and as a probiotic strain, adding to the potential health properties of fermented foods such as yoghurts.
The overall objective of the project was to investigate the relationships between food, veterinarian and clinical isolates of enterococci from different regions of Europe, and to study the functional and safety properties of selected strains.
Specific tasks included the establishment of a taxonomical collection and description of the biochemical and technological characteristics of enterococci and to establish their health promoting, as well as safety, characteristics - such as virulence, toxin production and antibiotic resistance.
In addition, the researchers - co-ordinated by professor Luc De Vuyst at Vrije Universiteit Brussel (VUB) - set out to determine their influence on the sensory properties of cheeses.
The scientists report that, of the many results obtained, they collected 405 well-described enterococci strains and characterised 145 of them, including attributes such as proteolytic and lipolytic activities, flavour development and biogenic amine production. Bacteriocin screening against 45 indicator microorganisms allowed a classification in eight classes - 72 strains (mainly E. faecium and E. faecalis) were bacteriocinogenic and some of these may be useful in starter cultures, controlling pathogens like Listeria or Clostridium, suggest the researchers.
They add that an industrial platform has been established to deal with the functional and safety aspects of these bacteria in food fermentations.
More information about project FAIR-CT97-3078 (ENTIP) can be obtained from Professor De Vuyst.