Standards Development

Scope

This document specifies a method for the detection and enumeration of Escherichia coli (E. coli)in soil improvers and growing media. This document applies to material in solid form (including pre-shaped growing media) and liquid form.

This document specifies a colony-count technique at 44°C on a solid medium containing a chromogenic ingredient for the detection of the enzyme ß-glucuronidase. Strains of Escherichia coli which do not grow at 44°C and, in particular, those that are ßglucuronidase negative, such as Escherichia coli O157, will not be detected.

Detected microorganisms are considered as presumptive β-glucuronidase positive Escherichia coli, since some Enterobacteriaceae, in particular Shigella and Salmonella, can also show βglucuronidase activity at 44°C. In the case the given limit value (e.g. [1]) is reached, a confirmation step (indole reaction) shall be performed.

Purpose

Appropriate analytical methods are necessary to check the conformity of CE marked soil improvers and growing media to the requirements of Regulation (EU) 2019/1009. In the Standardization Request M/564, a standard was requested describing the analytical method for the determination of the faecal bacterium Escherichia coli in soil improvers and growing media. A preliminary work item was previously registered within CEN/TC 223 ‘Soil improvers and growing media’; this form ensures the activation of the new work item and simultaneously the circulation of the first working draft.