prSRPS EN 17781:2025

Organic, organo-mineral and inorganic fertilizers - Enumeration of Escherichia coli

Scope

This document specifies a method for the enumeration of Escherichia coli (E. coli) in organic fertilizers, organo-mineral fertilizers, inorganic fertilizers which contain more than 1 % by mass of organic carbon, other than organic carbon from chelating or complexing agents, nitrification inhibitors, denitrification inhibitors or urease inhibitors, coating agents, urea or calcium cyanamide [1]. The method is tested for solid and liquid products.

This document is applicable to the fertilizing products blends where a blend is a mix of at least two of the following components: Fertilizers, Liming Materials, Soil Improvers, Growing Media, Inhibitors, Plant Biostimulants, and where the following category: organic fertilizers, organo-mineral fertilizers, inorganic fertilizer is the highest % in the blend by mass or volume, or in the case of liquid form by dry mass. If the organic fertilizer, the organo-mineral fertilizer or the inorganic fertilizer is not the highest % in the blend, the European Standard for the highest % of the blend applies. In case a fertilizing product blend is composed of components in equal quantity, the user decides which standard to apply.

Strains of E. coli which do not grow at 44 °C and, in particular, those that are β-D-glucuronidase negative, such as E. coli O157, will not be detected. Some genera within the family Enterobacteriaceae, in particular Shigella spp. and Salmonella spp., can also show β-D-glucuronidase activity at 44 °C.

NOTE: This method has been validated in an interlaboratory study with specific products that were present on the market during the study.

Related directives

NOTE: If the word "harmonized" (marked in green) is not found in the field with the name of the directive, it means that the European standard is not cited in the OJEU.