ČSN P CEN/TS 17781 (654944)

Anotace obsahu normy

This document is applicable to fertilizing products, which are classified as PFC 1(A) and PFC 1(B) or the PFC 1(A) and PFC 1(B) component in PFC 7 of Regulation (EU) 2019/1009. However, the present method was not validated for blends.
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. The method is based on ISO 16649-2.
Strains of Escherichia coli which do not grow at 44 °C and, in particular, those that are ß-glucuronidase negative, such as Escherichia coli O157, will not be detected. Detected microorganisms are presumptively determined ß-glucuronidase-positive Escherichia coli, since some Enterobacteriaceae, in particular Shigella and Salmonella, can also show ß-glucuronidase activity at 44 °C.