Mineral Modified Glutamate Agar - MMGA
new complete medium for the resuscitation
of sublethally injured E. coli.

To increase food safety and protect public health, the European Commission published a new regulation for analyzing foodstuff. It lays down e.g. safety criteria for the acceptability of food, particularly with regard to the presence of certain pathogenic microorganisms in foods.

This Regulation (EC) 2073/2005 on microbiological criteria for foodstuffs has been in force since January 1, 2006 and, as a consequence, all food business operators using this standard for the detection of E. coli must change their protocol, because the mandatory ISO standard in this regulation is the standard 16649 with its parts 1 and 2.

Part 1 describes a membrane method that includes a resuscitation step for E. coli. This step is necessary in case of food treatment, for example heating, drying, chemical preservation, freeze-drying or acidification, since this treatment damages and injures the bacteria. Using the current detection medium for E. coli of this standard, i.e. TBX agar, with its high amount of selective substances and the high incubation temperature of 44°C without resuscitation, it is possible to get false negative results as injured E. coli do not grow reliably. To minimize the risk, the ISO recommends the use of MMGA medium for this recovery step.

When food business operators prepared the MMGA in the past, they used e.g. DEV glutamate broth to which the agar had to be added. As other media used did not even contain glutamate, they also had to add a glutamate solution.

Now, for convenience, this new medium from Merck includes the glutamate and the agar and, of course, for safety reasons it is granulated. The unique combination of glutamate, selected minerals and agar results in a very rapid and effective resuscitation of injured E. coli and, after incubation for 4 hours at 37°C, most of the bacteria are sufficiently repaired so that growth on ChromoCult® TBX agar at 44°C is guaranteed.

For further information about the wide range of products available from Merck KGaA please contact Merck KGaA (contact details are at the top of this page).