EZ-CHROM* STEC is a chromogenic media for the detection of Shiga-Toxin producing E. coli (STEC). Product can be ordered as 20 prepared plates or 5L Packs (sufficient base powder & supplement to make 5 liters of Agar) of powdered media.


An increasing number of recent studies have shown that, non-O157 Shiga Toxin-producing E. coli (STEC) have been responsible for food poisoning outbreaks. The CDC has also reported warnings about this potential risk. As a result, several regulatory authorities have urged the food industry worldwide to implement measures to ensure the absence of such organisms in their production.

Disease caused by Shiga toxin-producing Escherichia coli (STEC) ranges from self-limiting diarrhea to hemorrhagic colitis and hemolytic uremic syndrome (HUS). Serotype O157:H7, the most frequently implicated STEC causing hemorrhagic colitis and HUS, has been isolated from large foodborne outbreaks, as well as sporadic cases, in North America and abroad. However, 60 STEC serotypes have been implicated in diarrheal disease, and several non-O157:H7 serotypes have been implicated as the cause of foodborne outbreaks and HUS in the United States, Europe, and Australia. Studies from Canada, Europe, Argentina, and Australia suggest that non- O157:H7 STEC infections are as prevalent, or more so, than O157:H7 infection.

CDC report Prevalence of Non-O157:H7 Shiga Toxin-Producing Escherichia coli in Diarrheal Stool Samples

In many cases laboratories have limited their search for pathogenic E. coli to the common O157 serotype. This is due to the fact that there were no available selective culture media for non-O157 E. coli. EZ-CHROM STEC is designed to fill this gap by producing mauve colonies of not only the classical O157 STEC but also many other STEC serotypes.


STEC E. coli serotypes will produce mauve colonies. E. coli non-STEC (ATCC 25922) will be inhibited. Other Enterobacteriacae will appear colorless, blue or inhibited; and gram positive bacteria will be inhibited.

*EZ-CHROM plates are a Colorex™ product, EZ-CHROM powder is a CHROMagar™ product