Guidelines for the examination of food samples during microbiological food safety testing recommend detection of the Enterobacteriaceae. In addition to coliforms, this group includes salmonellae and shigellae, which do not ferment lactose, and enterotoxigenic Escherichia coli. It also contains organisms, such as Klebsiella and Citrobacter, which are more resistant to heat than coliforms and are, therefore, better indicators of failure of processes that use minimal heat.

The difficulties of measuring the total Enterobacteriaceae content of food samples have been studied by Mossel³, who showed that the addition of glucose to an existing medium for the detection of coliforms improves the performance—as shown for Violet Red Bile Glucose Agar.

• Easy-to-read results: due to the inclusion of neutral red indicator and crystal violet in the medium Enterobacteriaceae form purple-pink colored colonies.

Violet Red Bile Glucose Agar has been developed to satisfy all of the below criteria of an approved media which complies with the recommendations of ISO:

• Media should be clear and yield colonies of satisfactory size to give reproducible counts of typical colonies of Enterobacteriaceae.
• When challenged for intrinsic toxicity by an anaerobic metabolic test using a strain of Yersinia enterocolitica (Serotype 03) as a sensitive indicator, media must promote adequate growth, acid formation and, where required, adequate gas formation.
• Media have to satisfy the confirmation rate of typical colonies, i.e., the number of colonies confirmed as Enterobacteriaceae divided by the number of colonies tested.

Not all products are available for sale in all territories. Please inquire.

Remel™ and Oxoid™ products are now part of the Thermo Scientific brand