prEN 18279

Soil improvers and growing media - Enumeration of enterococci

This document specifies a method for the enumeration of enterococci in soil improvers and growing media. This document is applicable to material in solid form (including pre-shaped growing media) and liquid form.
This document is applicable to fertilizing product blends, where a blend is a mix of two or more fertilising products belonging to the categories of fertilizers, liming material, soil improvers, growing media, inhibitors and plant biostimulants, and where soil improvers and/or growing media comprise the highest percentage in the blend by mass or volume, or in the case of liquid form by dry mass. If soil improvers and/or growing media do not comprise the highest percentage in the blend, the European Standard for the highest percentage in the blend applies. In case a blend is composed of fertilising products in equal quantity, the user of the standard decides which standard to apply.
NOTE 1   A soil improver or a growing medium consists of a single bulky (volume-building) component or a mix of bulky (volume-building) components (for example peat, wood fibres, coconut coir, compost, expanded perlite).
NOTE 2   This method has been validated in an interlaboratory study with specific products that were present on the market during the study (Annex C).

Bodenverbesserungsmittel und Kultursubstrate - Bestimmung von Enterococcacae

Amendements du sol et supports de culture - Dénombrement des Enterococcaceae

Soil improvers and growing media - Enumeration of enterococci

General Information

• Status: Not Published
• Publication Date: 28-Jun-2026
• ICS: 65.080 - Fertilizers
• Technical Committee: CEN/TC 223 - Soil improvers and growing media
• Drafting Committee: CEN/TC 223/WG 5 - Microbiology
• Current Stage: 4010 - Start of draft translation - Enquiry
• Start Date: 24-Oct-2025
• Completion Date: 09-Oct-2025
• Directive: 2003/2003 - Regulation (EC) N° 2003/2003 of the European Parlament and of the council of 13 October 2003 relating to fertilisers
• Directive: 2019/1009 - Regulation (EU) 2019/1009 of the European Parliament and of the Council of 5 June 2019 laying down rules on the making available on the market of EU fertilising products and amending Regulations (EC) No 1069/2009 and (EC) No 1107/2009 and repealing Regulation (EC) No 2003/2003
• Mandate: M/564 - Fertilising products in support of Regulation (EU) 2019/1009
• Mandate: M/564 AMD 1 - amending Implementing Decision C(2020) 612 as regards certain harmonised standards and standardisation deliverables, deadlines for their adoption and the duration of the validity of the standardisation request
• Mandate: M/564 AMD 2 - Commission Implementing decision amending Implementing Decision C(2020)612 as regards harmonised standards, the deadlines for the adoption of those standards and the duration of the validity of the standardisation request to the European Committee for Standardisation as regards the EU fertilising products in support of Regulation (EU) 2019/1009 of the European Parliament and of the Council
• Mandate: M/588 - COMMISSION IMPLEMENTING DECISION of 20.9.2022 on a standardisation request to the European Committee for Standardisation as regards methods for the measurements of emissions into the air of polychlorinated dibenzo-pdioxins and furans (PCDDs/PCDFs) and dioxin-like polychlorinated biphenyls (PCBs), total gaseous mercury and formaldehyde in support of Directive 2010/75/EU of the European Parliament and of the Council
• Mandate: M/XXX - COMMISSION IMPLEMENTING DECISION of XXX on a standardisation request to the European Committee for Standardization, to the European Committee for Electrotechnical Standardization and to the European Telecommunications Standards Institute as regards certain measuring instruments in support of Directive 2014/32/EU of the European Parliament and of the Council
• Ref Project: - Soil improvers and growing media - Enumeration of enterococci

Overview

prEN 18279 (CEN draft) specifies a harmonized method for the enumeration of enterococci in soil improvers and growing media. The standard covers both solid (including pre-shaped substrates) and liquid products and applies to fertilising product blends when soil improvers/growing media are the dominant component. The method is intended to support hygienic control, sanitation verification and regulatory compliance by providing a reproducible procedure to determine colony‑forming units (CFU) of enterococci per gram or millilitre.

Key topics and technical requirements

• Scope and applicability
  • Applies to solid and liquid soil improvers and growing media, including blends (rules for which standard applies are given when blends contain multiple fertilising product types).
  • Method validated in an interlaboratory study (Annex C).
• Principle
  • Spread plating of initial suspension or decimal dilutions onto Slanetz‑Bartley agar; incubation at 37 °C for ~46 h to enumerate presumptive enterococci (formazan-positive colonies).
  • Confirmation of presumptive colonies on Bile Esculin Azide (BEA) agar at 44 °C to demonstrate esculin hydrolysis (blackening).
  • Results expressed as CFU per g or mL following defined counting rules.
• Sampling and sample prep
  • Sampling is outside the method; follow EN 12579 and sample preparation per prEN 13040-2.
• Equipment and reagents
  • Typical microbiology lab equipment: incubators (37 °C, 44 °C), autoclave, water bath (47–50 °C), sterile pipettes, spreaders, Petri dishes, media prepared as per Annex B.
• Quality and validation
  • Guidance on plate selection, colony counting limits, confirmation criteria, and method performance characteristics (Annex C).
  • Recommendations for media performance testing per EN ISO 11133.
• Safety
  • Tests must be done in properly equipped labs under skilled supervision; standard references EN ISO 7218 for microbiological practice.

Applications and who uses it

• Microbiology laboratories performing routine hygiene testing of substrates and growing media.
• Manufacturers of soil improvers, composts, peat, wood fibre, coconut coir and pre‑mixed growing media for internal quality control.
• Third‑party testing and certification bodies verifying compliance with hygienic limit values (e.g., Regulation (EU) 2019/1009).
• Regulators, plant health authorities and agronomy consultants monitoring faecal contamination indicators and sanitation process effectiveness.
• Useful in product development, process validation, factory sanitation audits and research on microbial safety of growing media.

Related standards

• EN 12579 (Sampling of soil improvers and growing media)
• prEN 13040-2 (Sample preparation for microbiological examination)
• prEN 17732 (Terminology)
• EN ISO 7218 (Microbiology of the food chain - general lab practice)
• EN ISO 11133 (Media performance testing) and ISO/ISO 5725 guidance for validation

Keywords: enterococci enumeration, soil improvers, growing media, Slanetz‑Bartley agar, Bile Esculin Azide, CEN standard, microbiological testing, fertilising product blends.