Consider safety issues when using Enterococcus spp in foods.

The use of Enterococcus spp. in food products requires you to carefully evaluate the safety of these bacteria. There is an expanding range of bacterial cultures finding greater use in food products. There's also an increased interest in probiotics and their potential health benefits.

But a major issue of concern should be the safety of cultures that can be consumed live and in large quantities. Several species of lactic acid bacteria are used for this purpose. The most controversial of these are the enterococci. The genus Enterococcus is of particular medical relevance because of its increased incidence as a cause of disease, and because the available antibiotic therapies are being compromised by the bacteria's growing resistance to antibiotics.

Enterococcal cultures have found a place in dairy fermentations for decades, and isolates with histories of safe usage are being promoted as probiotic cultures. Still, these bacteria probably represent the largest risk to human health of any species currently used in this manner.

Microbiologists at the Institute of Food Research (IFR, Norwich Research Park, Colney, Norwich NR4 7UA, England, U.K.) have been able to identify patterns in the presence of both expressed and silent virulence genes in starter, food and medical enterococcal strains. For example, the presence of these virulence determinants in E. faecium strains may be significant in the evolution of pathogenic E. faecium strains. In addition, the scientists were able to show that virulence determinants can be transferred to starter strains by means of natural conjugation mechanisms.

Their results reinforce our concern about the safety of enterococcal strains used in foods. Any introduction of food products or probiotics based on the use of new enterococcal strains merits careful premarket safety screening and evaluation, according to the investigators.

Further information. Tracy Eaton; phone: [phone]; fax: [phone]; email: [e-mail].