Plant biostimulants - Determination of enterococci

This methodology has been developed to determine enterococci in biostimulants as a single microorganism component or in a mixture with other microorganisms. This document is not applicable to mineral fertilizers that are defined as complementary feeding stuffs composed mainly of minerals and containing at least 40 % crude ash (Council Directive 79/373/EEC) [3].

Pflanzen-Biostimulanzien - Bestimmung von enterococci

Dieses Verfahren wurde zur Bestimmung von Enterokokken in Biostimulanzien als einzelner Mikroorganismus-Bestandteil oder in einem Gemisch mit anderen Mikroorganismen entwickelt. Dieses Dokument ist nicht anwendbar auf mineralische Düngemittel, die als Ergänzungsfuttermittel festgelegt sind, hauptsächlich aus Mineralstoffen zusammengesetzt sind und mindestens 40 % Rohasche enthalten (Richtlinie 79/373/EWG) [3].

Biostimulants des végétaux - Détermination des enterococci

Cette méthodologie a été développée pour déterminer les entérocoques dans les biostimulants en tant que composant unique d’un microorganisme ou dans un mélange avec d’autres microorganismes. Le présent document ne s’applique pas aux engrais minéraux utilisés comme aliments complémentaires des animaux, principalement composés de minéraux et contenant au moins 40 % de cendres brutes (Directive du Conseil 79/373/CEE) [3].

Rastlinski biostimulanti - Določanje enterokokov (Enterococcaceae)

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oSIST prEN 17720:2023
Rastlinski biostimulanti - Ugotavljanje prisotnosti in števila enterokokov
Plant biostimulants - Determination of Enterococcaceae
Pflanzen-Biostimulanzien - Bestimmung von Enterococcaceae
Biostimulants des végétaux - Détermination des Enterococcaceae
Ta slovenski standard je istoveten z: prEN 17720
65.080 Gnojila Fertilizers
oSIST prEN 17720:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

oSIST prEN 17720:2023
oSIST prEN 17720:2023
prEN 17720
April 2023
ICS 65.080 Will supersede CEN/TS 17720:2022
English Version
Plant biostimulants - Determination of Enterococcaceae
Biostimulants des végétaux - Détermination des Pflanzen-Biostimulanzien - Bestimmung von
Enterococcaceae Enterococcaceae
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 455.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.



CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 17720:2023 E
worldwide for CEN national Members.

oSIST prEN 17720:2023
prEN 17720:2023 (E)
Contents Page
European foreword . 4
Introduction . 5
1 Scope . 7
2 Normative references. 7
3 Terms and definitions . 7
4 Principle . 8
5 Diluents, selective media and test kit for phenotypic characterization . 8
5.1 General . 8
5.2 Diluent for initial suspension and for serial dilutions . 8
5.3 Selective media . 8
5.4 Phenotypic characterization and confirmation . 8
6 Apparatus and glassware . 9
7 Sampling . 9
8 Preparation of test sample . 9
8.1 General . 9
8.2 Liquid – water-based formulations . 9
8.3 Liquid – oil-based (emulsifiable concentrate – EC) formulations . 9
8.4 Solid – wettable powder (WP) formulations . 10
8.5 Solid – water dispersible granules (WDG) formulations . 10
8.6 Solid – pellets, granules, microgranules (slow release) formulations . 10
– substrate . 10
8.7 Solid
9 Procedure . 10
9.1 Inoculation and incubation of the plates . 10
9.2 Evaluation of results. 10
9.3 Confirmation step on BEA . 11
9.4 Catalase test . 11
10 Expression of results . 11
11 Precision . 11
11.1 General . 11
11.2 Interlaboratory study . 11
11.3 Repeatability . 11
11.4 Reproducibility . 11
12 Test report . 11
Annex A (normative) Solutions, media . 13
A.1 Diluents for initial suspension and serial dilutions. 13
A.2 Selective media . 14
Annex B (informative) Repeatability and reproducibility of the method . 15
B.1 Materials used in the interlaboratory comparison study. 15
B.2 Interlaboratory comparison results. 15
oSIST prEN 17720:2023
prEN 17720:2023 (E)
Annex ZA (informative) Relationship of this European Standard and the essential requirements of
Regulation (EU) 2019/1009 making available on the market of EU fertilising products aimed to be
covered . 17
Bibliography . 18
oSIST prEN 17720:2023
prEN 17720:2023 (E)
European foreword
This document (prEN 17720:2023) has been prepared by Technical Committee CEN/TC 455 “Plant
Biostimulants”, the secretariat of which is held by AFNOR.
This document is currently submitted to the CEN enquiry.
This document will supersede CEN/TS 17720:2022.
This document has been prepared under a Standardization Request given to CEN by the European
Commission and the European Free Trade Association, and supports essential requirements of EU
Directive(s) / Regulation(s).
For relationship with EU Directive(s) / Regulation(s), see informative Annex ZA, which is an integral part
of this document.
oSIST prEN 17720:2023
prEN 17720:2023 (E)
This document was prepared by the experts of CEN/TC 455 “Plant Biostimulants”. The European
Committee for Standardization (CEN) was requested by the European Commission (EC) to draft
European standards or European standardization deliverables to support the implementation of
Regulation (EU) 2019/1009 of 5 June 2019 laying down rules on the making available on the market of
EU fertilising products (“FPR” or “Fertilising Products Regulation”). This standardization request,
presented as SR M/564 and M/564/Amd1, also contributes to the Communication on “Innovating for
Sustainable Growth: A Bio economy for Europe”. Working Group 5 “Labelling and denominations”, was
created to develop a work program as part of this standardization request.
Technical committee CEN/TC 455 “Plant Biostimulants” was established to carry out the work program
that will prepare a series of standards. The interest in biostimulants has increased significantly in Europe
as a valuable tool to use in agriculture. Standardization was identified as having an important role in
order to promote the use of biostimulants. The work of CEN/TC 455 seeks to improve the reliability of
the supply chain, thereby improving the confidence of farmers, industry, and consumers in biostimulants,
and will promote and support commercialization of the European biostimulant industry.
Biostimulants used in agriculture can be applied in multiple ways: to the soil, to plants, as seed
treatments, etc. A microbial plant biostimulant consists of a microorganism or a consortium of
microorganisms, as referred to in Component Material Category 7 of Annex II of the EU Fertilising
Products Regulation.
This document is applicable to all microbial biostimulants in agriculture.
Table 1 summarizes many of the agro-ecological principles and the role played by biostimulants.
Table 1 — Agro-ecological principles and the role played by biostimulants [1]
Increase biodiversity
By improving soil microorganism quality/quantity
Reinforce biological regulation and interactions
By reinforcing plant- microorganism interactions
— symbiotic exchanges i.e. mycorrhizae
— symbiotic exchanges i.e. rhizobiaceae/fabaceae
— secretions mimicking plant hormones (i.e. trichoderma)
By regulating plant physiological processes
— e.g. growth, metabolism, plant development…
Improve biogeochemical cycles
— improve absorption of nutritional elements
— improve bioavailability of nutritional elements in the soil
— stimulate degradation of organic matter
oSIST prEN 17720:2023
prEN 17720:2023 (E)
This methodology has been developed to enumerate enterococci and enable the European Commission
to control proper labelling of plant biostimulant products. It is mainly based on EN 15788:2009, Animal
feeding stuffs — Isolation and enumeration of Enterococcus (E. faecium) spp. The method is based on an
extensive screening of 12 pre-selected, commercially available media for the detection and enumeration
of enterococci. The described methodology was validated in an interlaboratory study [2].
WARNING — Persons using this document should be familiar with normal laboratory practice. This
document does not purport to address all of the safety problems, if any, associated with its use. It is the
responsibility of the user to establish appropriate safety and health practices and to ensure compliance
with any national regulatory conditions.
IMPORTANT — It is absolutely essential that tests conducted in accordance with this document be
carried out by suitably trained staff.
oSIST prEN 17720:2023
prEN 17720:2023 (E)
1 Scope
This methodology has been developed to determine enterococci in biostimulants as a single
microorganism component or in a mixture with other microorganisms. This document is not applicable
to mineral fertilizers that are defined as complementary feeding stuffs composed mainly of minerals and
containing at least 40 % crude ash (Council Directive 79/373/EEC) [3].
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenc

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