Bifidobacteria may indicate hygienic quality of dairy, meats.

The two main groups of microorganisms believed to be therapeutically beneficial as probiotics are the lactobacilli and the bifidobacteria. But bifidobacteria may have other uses as well. Bifidobacteria--bacteria belonging to the genus Bifidobacterium--may be valuable indicators of the hygienic quality of dairy and meat raw products and nonpreserved products, such as raw milk cheeses and meat cuttings.

A goal of European scientists is to define a new standard using bifidobacteria in order to point out unsatisfactory hygienic conditions of raw materials and food products. Bifidobacteria are effective indicators of fecal contamination for several reasons:

* They are one of the major bacterial groups in human and animal feces.

* The dominant Bifidobacterium species are different in human and in animal flora. So, the contamination route may be identifiable.

* The bacteria are anaerobes and cannot multiply in most foods.

Investigators have been able to obtain relevant data on the Bifidobacterium species within raw materials and from different contamination sources and plant types. Researchers also have calculated a measure of hygiene standards on farms, based on the number and level of contaminated samples gathered from each farm. More than 80% of all raw milk samples are contaminated by bifidobacteria, in which the most frequent species is B. pseudolongum, and the next most frequent is B. thermophilum. Both are from animal origin.

Future research will involve undertaking more contamination studies covering raw milk cheese and meat (chicken and mutton). Scientists will determine the relationship between bifidobacteria and traditional indicators (total viable counts and E. coli) and between bifidobacteria and potential pathogenic bacteria (Salmonella spp., Aeromonas and S. aureus).

In addition, a specific polymerase chain reaction will be used to detect the most frequently occurring bifidobacteria species. The research participants intend to suggest that their new standard be used within the European directives that deal with the sanitary quality of raw milk, cheese made with raw milk, meat and meat products. The current standard is based on total viable counts of E. coli levels.

Further information. Francoise Gavini, INRA, 369, rue Jules Guesde, B.P. 39, 59650 Villeneuve d'Ascq, France; phone: [phone]; fax: [phone]; email: [e-mail].