scope:

This document specifies a horizontal method for the enumeration of β-glucuronidase-positive Escherichia coli by colony-count technique after resuscitation using membranes and incubation at 44 °C on a solid medium containing a chromogenic ingredient for detection of the enzyme β-glucuronidase^{[9][10][13][14][17][ 18][19][20]}. It is applicable to

- products intended for human consumption,

- products intended for feeding animals,

- environmental samples in the area of food production and food handling, and

- samples from the primary production stage such as animal faeces, dust, and swabs.

WARNING - Some strains of Escherichia coli may grow poorly or not at all in media incubated at 44 °C. This includes strains of E. coli O157:H7 and O157:H-. Additionally, some strains of Escherichia coli, notably those belonging to serotype O157:H7, are mostly β-glucuronidase negative^[11]. Consequently, some strains of E. coli, including pathogenic ones, will not be detected by this method. β-glucuronidase activity may also be exhibited at 44 °C by certain other members of the Enterobacteriaceae, notably Shigella^[15] and Salmonella^[16] .