Standards Development

Scope

This standard specifies a horizontal method for the enumeration of enterococci as faecal indicators in food, feed and environmental samples by the colony-count technique on a selective solid medium (Slanetz and Bartley agar) by an identification scheme based on tetrazolium reduction and formazan production following by confirmation based on split aesculin at 44°C on Bile Aesculin azide Agar.

Purpose

Enterococci as a part of the normal microflora in the gastrointestinal tract and the faeces of vertebrates can be found in different environments and can contaminate food and water. Due to their ability to survive in the environment, their pronounced heat resistance and the fact that they can dominate the microbial population of heat-treated foods, this group of bacteria can be used as indicators for hygienic and faecal contamination of food and feed. Enterococci are now considered as a hygienic factor in many food categories, especially dairies, animal feed, spices and herbs. A survey at the TC 34/SC 9 level displayed that Enterococci are tested in 9 food categories according to the national legislations in many countries. The range of expected contamination is 10- 1000 cfu/g, ml and not more than 104 cfu/g, ml is allowed by legislations.

Because of the above reasons enumeration and detection of Enterococci are of the important hygienic factors in water and many food categories. The ISO 7899-1 & 2 provide test methods for enumeration of Enterococci in water and a standardized test method is also needed for enumeration of Enterococci in food chain.