CHROMOGENIC ECO157:H7 SELECTIVE AGAR BASE, MODIFIED *

Escherichia coli O157:H7 belongs to the Enterohemorrhagic Escherichia coli (EHEC) group and it predominates as a food borne pathogen. E.coli O157:H7 was first recognized as a human pathogen in 1982 when two outbreaks of hemorrhagic colitis were associated with consumption of undercooked ground beef that has been contaminated with this organism that results from the action of a shiga-like toxin (SLT). This medium is recommended for isolation of enteropathogenic Escherichia coli O157:H7 in meats, poultry, dairy foods, infant formula, liquid eggs, mayonnaise and apple cider. The medium is based on three differential biochemical reactions – lysine decarboxylase (positive for typical EHEC O157 strains), sorbitol fermentation and beta-glucuronidase. This medium is also used for the enumeration of beta- glucuronidase-positive E.coli from foods.

for presumptive enumeration of Escherichia coli 0157:H7 by membrane ?ltration technique from food samples.