Plant biostimulants - Detection of Staphylococcus aureus

This document provides a method for verifying that the pathogen Staphylococcus aureus is absent from microbial plant biostimulants according to the limits outlined in the EU Regulation on Fertilising Products [2].

Pflanzen-Biostimulanzien - Nachweis von Staphylococcus aureus

Dieses Dokument stellt ein Verfahren zur Verfügung, mit dem verifiziert werden kann, dass das Pathogen Staphylococcus aureus in Pflanzen-Biostimulanzien die Grenzwerte der EU Düngeprodukteverordnung [2] nicht überschreitet.

Biostimulants des végétaux - Détection de Staphylococcus aureus

Le présent document fournit une méthode permettant de vérifier que le pathogène Staphylococcus aureus est absent dans les biostimulants microbiens des végétaux dans le respect des limites énoncées dans le Règlement UE sur les fertilisants [2].

Rastlinski biostimulanti - Ugotavljanje prisotnosti Staphylococcus aureus

General Information

Status
Not Published
Public Enquiry End Date
02-Jun-2023
Technical Committee
Current Stage
4020 - Public enquire (PE) (Adopted Project)
Start Date
21-Mar-2023
Due Date
08-Aug-2023
Completion Date
02-Aug-2023

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SLOVENSKI STANDARD
oSIST prEN 17712:2023
01-maj-2023
Rastlinski biostimulanti - Ugotavljanje prisotnosti Staphylococcus aureus
Plant biostimulants - Detection of Staphylococcus aureus
Pflanzen-Biostimulanzien - Nachweis von Staphylococcus aureus
Biostimulants des végétaux - Détection de Staphylococcus aureus
Ta slovenski standard je istoveten z: prEN 17712
ICS:
65.080 Gnojila Fertilizers
oSIST prEN 17712:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN 17712:2023


DRAFT
EUROPEAN STANDARD
prEN 17712
NORME EUROPÉENNE

EUROPÄISCHE NORM

April 2023
ICS 65.080 Will supersede CEN/TS 17712:2022
English Version

Plant biostimulants - Detection of Staphylococcus aureus
Biostimulants des végétaux - Détection de Pflanzen-Biostimulanzien - Nachweis von
Staphylococcus aureus Staphylococcus aureus
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.


EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATIO N

EUROPÄISCHES KOMITEE FÜR NORMUN G

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 17712:2023 E
worldwide for CEN national Members.

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Contents Page
European foreword . 4
Introduction . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Principle . 8
5 Sampling . 8
6 Preparation of test sample . 8
7 Procedure . 8
7.1 General . 8
7.2 Diluent . 8
7.3 Modified Giolitti-Cantoni broth . 9
7.4 Baird-Parker agar medium . 9
8 Apparatus and glassware . 9
9 Procedure . 10
9.1 Test portion, initial suspension and dilutions . 10
9.1.1 General . 10
9.1.2 Solid formulations . 10
9.1.3 Liquid formulations . 10
9.2 Enrichment and isolation . 10
9.3 Selection of plates and interpretation . 11
10 Precision . 11
11 Test report . 11
12 Performance characteristics of the method . 11
12.1 Interlaboratory studies . 11
12.2 Sensitivity . 12
12.3 Specificity . 12
12.4 Positive predictive value (PPV) . 12
12.5 Negative predictive value (NPV) . 12
Annex A (normative) Media composition and preparation . 13
A.1 Baird Parker Rabbit Plasma Fibrinogen (RPF) agar [4], [5], [6] . 13
A.2 Buffered peptone water (BPW) . 13
A.3 Modified Giolitti-Cantoni broth . 13
A.3.1 Base medium . 13
A.3.2 Potassium tellurite solution . 14
A.3.3 Complete medium (modified Giolitti-Cantoni broth) . 14
Annex B (informative) Repeatability and reproducibility of the method . 15
B.1 Materials used in the interlaboratory comparison study . 15
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B.2 Interlaboratory comparison results . 15
B.3 Contingency table analysis . 16
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

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European foreword
This document (prEN 17712:2023) 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 17712:2022.
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.

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Introduction
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”. The Working
Group 5 “Labelling and denominations”, was created to develop a work program as part of this
request. The 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
commercialisation of the European biostimulant industry.
Biostimulants used in agriculture can be applied in multiple ways to the soil, to plants, as seed
treatment, 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.
The Table 1 below 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
- such as growth, metabolism or plant development…
Improve biogeochemical cycles
- improve absorption of nutritional elements
- improve bioavailability of nutritional elements in the soil
- stimulate degradation of organic matter

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.
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IMPORTANT — It is absolutely essential that tests conducted in accordance with this document
be carried out by suitably trained staff.

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1 Scope
This document provides a method for verifying that the pathogen Staphylococcus aureus is absent
from microbial plant biostimulants according to the limits outlined in the EU Regulation on
Fertilising Products [2].
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 referenced document (including any
amendments) applies.
1
prEN 17724:— , Plant biostimulants — Terminology
3 Terms and definitions
2
For the purposes of this document, the terms and definitions given in prEN 17724:— and the
following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
— IEC Electropedia: available at https://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
3.1
Staphylococcus aureus
bacterium which forms colonies fitting the description of the species on the specified selective
medium after incubation for 24 h at a temperature of 37 °C under aerobic conditions
Note 1 to entry: S. aureus colony description:
— circular;
— convex;
— entire margin;
— grey to black (due to the reduction of potassium tellurite to telluride).
Note 2 to entry: Colony size varies between 1 mm and 2 mm in diameter.
Note 3 to entry: S. aureus is a facultatively anaerobic, Gram-positive coccus, which appears as grape-like
clusters when visualized under a microscope, and has a round, usually golden-yellow colonies, often with
haemolysis, when grown on selective blood agar plates.
Note 4 to entry: The term ‘Coagulase-positive staphylococci’ refers to bacteria that form typical and/or
atypical colonies on the surface of a selective culture medium and show a positive coagulase reaction when
the test is performed following the method specified in this document.

1
Under preparation. Stage at the time of publication: prEN 17724:2023.
2
Under preparation.
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3.2
detection of the coagulase-positive staphylococci
determination of the detection or non detection of Staphylococcus aureus (3.2), in 25 g or 25 ml of
product, when tests are carried out in accordance with this document
4 Principle
After sample preparation that is specific to microbial biostimulants, for detection of
Staphylococcus aureus, refer to the sections of EN ISO 6888-3:2003 that are pertinent to the
physical/chemical nature of the test sample for the detection of Staphylococcus aureus. If the
product is liquid, a specified volume of the test sample will be inoculated onto a liquid selective
culture medium. For products formulated differently, a specified volume of an initial suspension
will be inoculated onto the selective medium. Incubation is under anaerobic conditions at 37 °C
for 24 and 48 h.
Pour plate and spread plate techniques could be used. Spread plate is considered enough for
detecting the presence of this species. In this case, the inoculation could be done with a sterile
loop (containing around 10 μl of product, dilution or suspension) to obtain isolated colonies
without proceeding with the pour plating method, which is usually used for enumeration.
If pour plating is pursued, the following steps should be considered. Solid selective culture
medium by pour-plating, with a specified quantity of the initial suspension. Inoculation, under the
same conditions, using decimal dilutions of the initial suspension. Aerobic incubation of the plates
at 37 °C and examination after both 24 h and 48 h if necessary. The result is given as the presence
or absence of the germ of interest in a test portion of 25 g or 25 ml.
5 Sampling
3
Sampling is not part of the method specified in this document (see prEN 17702-1 dealing with
the product concerned). If there is no specific International or European Standard, it is
recommended that the parties concerned come to an agreement on this subject.
It is important that the laboratory receives a sample which is representative and has not been
altered during transport or storage.
6 Preparation of test sample
The initial suspension is prepared from at least 25 g or 25 ml of the well-mixed product to the
appropriate amount of diluent to give a 1:10 dilution ratio. This is to ensure that a representative
sample of the product materials is obtained.
7 Procedure
7.1 General
After sample preparation that is specific to microbial biostimulants, for detection of
Staphylococcus aureus, see EN ISO 6888 for the detection of Staphylococcus aureus for this method.
7.2 Diluent
See EN ISO 6887-1 and the specific standard dealing with the product to be analysed.

3
Under preparation.
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7.3 Modified Giolitti-Cantoni broth
See Annex A.
7.4 Baird-Parker agar medium
See Annex A.
8 Apparatus and glassware
Usual microbiological laboratory equipment (for additional details refer
...

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