oSIST prEN 17422:2019

Chemical disinfectants and antiseptics - Quantitative surface test for the evaluation of teat disinfectants used in the veterinary area - Test method and requirements (phase 2 step 2)

This procedure specifies a test method and the minimum requirements for bactericidal activity of teat disinfectants that form a homogeneous, physically stable preparation when diluted with hard water - or in the case of ready-to-use products - with water.
This method applies to teat disinfectants that are used in the veterinary area on teat skin without mechanical action as pre-milking and/or post-milking teat disinfectants.
NOTE 1 The method described is intended to determine the activity of commercial formulations under the conditions in which they are used.
NOTE 2 This method corresponds to a phase 2 step 2 test.
NOTE 3 Two types of synthetic skin were assessed in a ring trial with no significant difference in performance. Other synthetic skins may become available and may be used if it can be shown that they give comparable results to the two referenced in this standard.

Chemische Desinfektionsmittel und Antiseptika - Quantitativer Oberflächenversuch zur Beurteilung von Zitzendesinfektionsmittel für den Veterinärbereich - Prüfverfahren und Anforderungen (Phase 2, Stufe 2)

Antiseptiques et désinfectants chimiques - Essai quantitatif de surface pour l’évaluation des désinfectants de trayons utilisés dans le domaine vétérinaire - Méthode d’essai et prescriptions (phase 2, étape 2)

Kemična razkužila in antiseptiki - Kvantitativni površinski preskus brez mehanskega delovanja za vrednotenje razkužil za seske v veterini - Preskusna metoda in zahteve (faza 2, stopnja 2)

General Information

• Status: Not Published
• Public Enquiry End Date: 02-Oct-2019
• ICS: 11.080.20 - Disinfectants and antiseptics
• ICS: 11.220 - Veterinary medicine
• Technical Committee: KDS - Cosmetics, chemical disinfectants and surface active agents
• Current Stage: 4020 - Public enquire (PE) (Adopted Project)
• Start Date: 19-Jun-2019
• Due Date: 06-Nov-2019
• Completion Date: 18-Sep-2019
• Ref Project: prEN 17422 - Chemical disinfectants and antiseptics - Quantitative surface test for the evaluation of teat disinfectants used in the veterinary area - Test method and requirements (phase 2 step 2)

Standards Content (sample)

SLOVENSKI STANDARD
oSIST prEN 17422:2019
01-september-2019
Kemična razkužila in antiseptiki - Kvantitativni preskus brez mehanskega
delovanja za vrednotenje razkužil za seske v veterini - Preskusna metoda in
zahteve (faza 2, stopnja 2)

Chemical disinfectants and antiseptics - Quantitative surface test for the evaluation of

teat disinfectants used in the veterinary area - Test method and requirements (phase 2

step 2)

Chemische Desinfektionsmittel und Antiseptika - Quantitativer Oberflächenversuch zur

Beurteilung von Zitzendesinfektionsmittel für den Veterinärbereich - Prüfverfahren und

Anforderungen (Phase 2, Stufe 2)

Antiseptiques et désinfectants chimiques - Essai quantitatif de surface pour l’évaluation

des désinfectants de trayons utilisés dans le domaine vétérinaire - Méthode d’essai et

prescriptions (phase 2, étape 2)
Ta slovenski standard je istoveten z: prEN 17422
ICS:
11.080.20 Dezinfektanti in antiseptiki Disinfectants and antiseptics
11.220 Veterinarstvo Veterinary medicine
oSIST prEN 17422:2019 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN 17422:2019
DRAFT
EUROPEAN STANDARD
prEN 17422
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2019
ICS 71.100.35
English Version
Chemical disinfectants and antiseptics - Quantitative
surface test for the evaluation of teat disinfectants used in
the veterinary area - Test method and requirements
(phase 2 step 2)

Antiseptiques et désinfectants chimiques - Essai Chemische Desinfektionsmittel und Antiseptika -

quantitatif de surface pour l'évaluation des Quantitativer Oberflächenversuch zur Beurteilung von

désinfectants de trayons utilisés dans le domaine Zitzendesinfektionsmittel für den Veterinärbereich -

vétérinaire - Méthode d'essai et prescriptions (phase 2, Prüfverfahren und Anforderungen (Phase 2, Stufe 2)

étape 2)

This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee

CEN/TC 216.

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, Turkey 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 NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels

© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 17422:2019 E

worldwide for CEN national Members.
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Contents Page

European foreword ....................................................................................................................................................... 3

Introduction..................................................................................................................................................................... 4

1 Scope .................................................................................................................................................................... 5

2 Normative references .................................................................................................................................... 5

3 Terms and definitions.................................................................................................................................... 5

4 Requirements ................................................................................................................................................... 6

5 Test method ....................................................................................................................................................... 6

5.1 Principle ............................................................................................................................................................. 6

5.2 Materials and reagents .................................................................................................................................. 6

5.2.1 Test organisms ................................................................................................................................................. 6

5.2.2 Culture media and reagents ......................................................................................................................... 7

5.2.3 Test surface - synthetic skin ........................................................................................................................ 8

5.3 Apparatus and glassware ............................................................................................................................. 9

5.3.1 General ................................................................................................................................................................ 9

5.4 Preparation of test organism suspension and product test solutions ...................................... 10

5.4.1 Test organism suspension (test and validation suspension) ....................................................... 10

5.4.2 Product test solution ................................................................................................................................... 11

5.5 Procedure for assessing the bactericidal activity of the product ............................................... 11

5.5.1 General ............................................................................................................................................................. 11

5.5.2 Test procedure .............................................................................................................................................. 12

5.6 Experimental data and calculation ........................................................................................................ 14

5.6.1 Explanation of terms and abbreviations .............................................................................................. 14

5.6.2 Calculation ...................................................................................................................................................... 15

5.7 Verification of methodology ..................................................................................................................... 17

5.7.1 General ............................................................................................................................................................. 17

5.7.2 Control of weighted mean counts ........................................................................................................... 17

5.7.3 Basic limits ...................................................................................................................................................... 17

5.8 Expression of results and precision....................................................................................................... 18

5.8.1 Reduction......................................................................................................................................................... 18

5.8.2 Control of active and non-active product test solution (5.4.2) .................................................... 18

5.8.3 Limiting test organism and bactericidal concentration ................................................................. 18

5.8.4 Precision, repetitions .................................................................................................................................. 18

5.9 Interpretation of results – conclusion .................................................................................................. 18

5.9.1 General ............................................................................................................................................................. 18

5.9.2 Bactericidal activity for teat disinfection ............................................................................................ 19

5.10 Test report ...................................................................................................................................................... 19

Annex A (informative) Referenced strains in national collections ......................................................... 21

Annex B (informative) Examples of neutralizers of the residual antimicrobial activity of

chemical disinfectants and antiseptics and rinsing liquids .......................................................... 22

Annex C (informative) Example of a typical test report .............................................................................. 23

Bibliography ................................................................................................................................................................. 26

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European foreword

This document (prEN 17422:2019) has been prepared by Technical Committee CEN/TC 216 “Chemical

disinfectants and antiseptics”, the secretariat of which is held by AFNOR.
This document is currently submitted to the CEN Enquiry.
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Introduction

This document specifies a surface test for establishing whether a teat disinfectant, for use on teat skin

without mechanical action, in the veterinary area, has or does not have bactericidal activity under the

laboratory conditions defined by this document, which influence the action of disinfectants in practical

use.

The laboratory test takes into account practical conditions of application of the product including

applying test organisms and interfering substances on a synthetic skin surface, contact time and

temperature, i.e. conditions which may influence its action in practical situations. The method is based

on EN 16437 Chemical disinfectants and antiseptics - Quantitative surface test for the evaluation of

bactericidal activity of chemical disinfectants and antiseptics used in the veterinary area on porous

surfaces without mechanical action - Test method and requirements (phase 2, step 2).

In this document synthetic human skin is used as the test surface.
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1 Scope

This procedure specifies a test method and the minimum requirements for bactericidal activity of teat

disinfectants that form a homogeneous, physically stable preparation when diluted with hard water - or

in the case of ready-to-use products - with water.

This method applies to teat disinfectants that are used on teat skin without mechanical action as pre-

milking and/or post-milking teat disinfectants in the veterinary area - i.e. in the breeding, husbandry,

production, veterinary care facilities, transport and disposal of all animals except when in the food chain

following death and entry into processing industry.

NOTE 1 The method described is intended to determine the activity of commercial formulations under the

conditions in which they are used.
NOTE 2 This method corresponds to a phase 2 step 2 test.

NOTE 3 Two types of synthetic skin were assessed in a ring trial with no significant difference in performance.

One has been chosen as the test surface because it is commercially available. Other synthetic skins can become

available and can be used if it shown that they give comparable results to the one referenced in this standard.

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.

EN 1656, Chemical disinfectants and antiseptics — Quantitative suspension test for the evaluation of

bactericidal activity of chemical disinfectants and antiseptics used in the veterinary area — Test method

and requirements (phase 2, step 1)

EN 12353, Chemical disinfectants and antiseptics — Preservation of test organisms used for the

determination of bactericidal (including Legionella), mycobactericidal, sporicidal, fungicidal and virucidal

(including bacteriophages) activity

EN 14885, Chemical disinfectants and antiseptics — Application of European Standards for chemical

disinfectants and antiseptics
3 Terms and definitions

For the purposes of this document, the terms and definitions given in EN 14885 apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obpuirements
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4 Requirements

The product shall demonstrate at least a 4 decimal log (lg) (post-milking disinfectant) or 3 decimal log

(lg) (pre-milking disinfectant) reduction from a water control, when tested in accordance with Table 1

and Clause 5 under simulated soiling (10,0 g/l milk powder or 3,0 g/l bovine albumin).

Table 1 — Requirements
Bactericidal activity on synthetic skin
Test Conditions
without mechanical action
- Escherichia coli
Test organism
- Staphylococcus aureus
Test temperature 30°C ± 1°C
Minimum Maximum
Contact time
Up to 1 min at For times > 1 min at
intervals of 30 s intervals of 1 min
Post milking teat disinfectants 1 min ± 5 s 5 min ± 10 s
Pre-milking teat disinfectants 30 s ± 5 s 3 min ± 10 s
Interfering substance
10,0 g/l milk powder
Post milking teat disinfectants
3,0 g/l bovine albumin
Pre-milking teat disinfectants
5 Test method
5.1 Principle

A test suspension of bacteria mixed with interfering substance is inoculated onto a synthetic skin surface

and maintained at 30 °C for a period of conditioning.

After this conditioning time, the skin surface is immersed in the product or dilutions of the product at

30 °C for a defined period of time specified in Table 1. At the end of that contact time, neutralizer is added

so that the action of the disinfectant is immediately neutralized.

The bacteria are removed from the surface by ultrasound treatment. The numbers of surviving bacteria

which can be recovered from the surface are determined quantitatively.

The number of bacteria on a surface treated with water in place of the disinfectant is also determined and

the reduction is calculated.
5.2 Materials and reagents
5.2.1 Test organisms

The bactericidal activity shall be evaluated using the following strains as test organisms :

- Escherichia coli ATCC 10536
- Staphylococcus aureus ATCC 6538

NOTE The ATCC numbers are the collection numbers of strains supplied by the American Type Culture

Collections (ATCC).
Refer to Annex A for strain references in some other culture collections.

The required incubation temperature for these organisms is 36 °C ± 1 °C or 37 °C ± 1 °C (5.3.2.3).

The ATCC numbers are the collection numbers of strains supplied by the American Type Culture Collection

(ATCC). This information is given for the convenience of users of this document and does not constitute an

endorsement by CEN of the product named.
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5.2.2 Culture media and reagents
5.2.2.1 General

All weights of chemical substances given in this method refer to the anhydrous salts. Hydrated forms may

be used as an alternative, but the weights required shall be adjusted to allow for consequent molecular

weight differences.

The reagents shall be of analytical grade and/or appropriate for microbiological purposes. They shall be

free from substances that are toxic or inhibitory to the test organisms.

To improve reproducibility, it is recommended that commercially available dehydrated material is used

for the preparation of culture media. The manufacturer's instructions relating to the preparation of these

products should be rigorously followed.

A ready-to-use medium may be used if it complies with the required specification.

For each culture medium and reagent, a time limitation for use should be fixed.
5.2.2.2 Water

The water shall be freshly glass-distilled water and not demineralized water. If distilled water of adequate

quality is not available, water for injections (see bibliographic reference [2]) may be used.

Sterilize in the autoclave [5.3.2.1 a)]. Sterilization is not necessary if the water is used e.g. for preparation

of culture media and subsequently sterilized.
5.2.2.3 Tryptone soya agar (TSA)
Tryptone soya agar, consisting of:
Tryptone, pancreatic digest of casein 15,0 g;
Soya peptone, papaic digest of soybean meal 5,0 g;
Sodium chloride (NaCl) 5,0 g;
Agar 15,0 g;
Distilled Water to 1 000,0 ml.

Sterilize in the autoclave as above. After sterilization the pH of the medium shall be equivalent to 7,2 ± 0,2

when measured at (20 ± 1) °C.
5.2.2.4 Diluent
Tryptone sodium chloride solution, consisting of:
Tryptone, pancreatic digest of casein 1,0 g;
Sodium chloride (NaCl) 8,5 g;
Distilled Water to 1 000,0 ml

Dispense in 9 ml portions and sterilize in the autoclave as above. After sterilization, the pH of the diluent

shall be equivalent to 7,0 ± 0,2 when measured at (20 ± 1) °C.
5.2.2.5 Neutralizer

The neutralizer shall be validated for the product being tested in accordance with 5.5.1.2. It shall be

sterile.

NOTE Information on neutralizers that have been found to be suitable for some categories of products is given

in Annex B.
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5.2.2.6 Standardized hard water
For the preparation of 1 l of hard water, the procedure is as follows:
Prepare solution A:

Dissolve 19,84 g magnesium chloride (Mg Cl ) and 46,24 g calcium chloride (Ca Cl ) in distilled water

2 2

and dilute to 1 000 ml. Sterilize by membrane filtration or in the autoclave. Autoclaving - if used - may

cause a loss of liquid. In this case make up to 1 000 ml with water under aseptic conditions. Store the

solution in the refrigerator (5.3.2.8) at 2-8 °C for no longer than one month.
Prepare solution B:

Dissolve 35,02 g sodium bicarbonate (NaHCO3) in distilled water and dilute to 1 000 ml. Sterilize by

membrane filtration. Store the solution in the refrigerator (5.3.2.8) at 2-8 °C for no longer than one week.

Place 600 ml to 700 ml of sterile distilled water in a sterile 1 000 ml volumetric flask and add 6,0 ml of

solution A, then 8,0 ml of solution B. Mix and dilute to 1 000 ml with sterile distilled water. The pH of the

hard water shall be 7,0 ± 0,2 when measured at (20 ± 1) °C. If necessary, adjust the pH by using a solution

of approximately 40 g/l (about 1 mol/l) of sodium hydroxide (NaOH) or approximately 36,5 g/l (about

1 mol/l) of hydrochloric acid (HCl).

The hard water shall be freshly prepared under aseptic conditions and used within 12 h.

5.2.2.7 Interfering substances, shall be sterile and prepared at 2 times its final concentration in the

test.

5.2.2.7.1 Skimmed milk, guaranteed free of antibiotics and additives and prepared as follows:

— prepare a solution of 20 g milk-powder in 1 000 ml water (5.2.2.2).
+3 +3
— Heat for 30 min at 105 °C (or 5 min at 121 °C).
0 0
The final concentration in the test procedure (5.5) is 10g/l milk powder.
5.2.2.7.2 Bovine albumin solution

Dissolve 0,6 g of bovine albumin (Cohn fraction V for Dubos Medium) in 90 ml of water (5.2.2.2) in a

100 ml volumetric flask. Make up to the mark with water (5.2.2.2).

Sterilize by membrane filtration (5.3.2.7). Keep in the refrigerator (5.3.2.8) at 2-8 °C and use within one

month.

The final concentration of the bovine albumin in the test procedure (5.5.2) is 3 g/l.

5.2.3 Test surface - synthetic skin
5.2.3.1 Vitro skin

Handle skin with sterile tweezers/implements. Eight pieces are used for each test: 3 for the test dilutions,

1 for the water control, 1 for control B, 2 for control C (1 inoculated and 1 un-inoculated) and 1 for a

sterility check.

Vitroskin: Mark with a pencil and ruler on the outside of the sealed skin packet eight 2 × 2 cm squares

(per test). Cut using sterile scissors and re-hydrate for 16 to 24 h before use (follow instructions provided

from the supplier). When ready to start the test, place each piece in a sterile wide necked vessel, with lid

on.

Vitro skin may be obtained from IMS Inc., 110 Marginal Way, PMB 155, Portland ME 04101-2497 USA. This

information is given for the convenience of users of this document and does not constitute an endorsement by CEN

of the product named.
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5.3 Apparatus and glassware
5.3.1 General

Sterilize all glassware and parts of the apparatus that will come into contact with the culture media and

reagents or the sample, except those which are supplied sterile, by one of the following methods:

a) by moist heat, in an autoclave;
b) by dry heat, in a hot air oven
5.3.2 Usual microbiological equipment ,and in particular, the following:
5.3.2.1 Apparatus for sterilization (dry and moist heat):

a) for moist heat sterilization, an autoclave capable of being maintained at (121 ) °C for a minimum

holding time of 15 min;
) °C for a minimum

b) for dry heat sterilisation, a hot air oven capable of being maintained at (180

+5 +5

holding time of 30 min, at (170 ) °C for a minimum holding time of 1 h or at (160 ) °C for a

0 0
minimum holding time of 2 h.

5.3.2.2 Water bath, capable of being controlled at (20 ± 1) °C, (30 ± 1) °C, and (45 ± 1) °C.

5.3.2.3 Incubator, capable of being controlled at (30 ± 1) °C, (36 ± 1) °C or (37 ± 1) °C.

5.3.2.4 pH-meter, having an inaccuracy of calibration of no more than ± 0,1 pH units at (20 ± 1) °C.

A puncture electrode or a flat membrane electrode should be used for measuring the pH of the agar-

media.
5.3.2.5 Stopwatch
5.3.2.6 Shakers
a) Electromechanical agitator, e.g. Vortex® mixer
b) Mechanical shaker.

5.3.2.7 Membrane filtration apparatus, constructed of a material compatible with the substances

to be filtered with a filter holder of at least 50 ml volume and suitable for use with filters of diameter

47 mm to 50 mm and 0,45 µm pore size for sterilization of hard water (5.2.2.6) and bovine albumin

(5.2.2.7.2).
5.3.2.8 Refrigerator, capable of being controlled at 2 °C to 8 °C.

5.3.2.9 Graduated pipettes of nominal capacities 10 ml, 1 ml, 0,1 ml and 0,05 ml or calibrated

automatic pipettes.
5.3.2.10 Petri dishes, (plates) of size 90 mm to 100 mm.
5.3.2.11 Glass beads (diameter 3 mm to 4 mm).
5.3.2.12 Volumetric flasks
Disposable sterile equipment is an acceptable alternative to reusable glassware.

Vortex® is an example of a suitable product available commercially. This information is given for the

convenience of users of this document and does not constitute an endorsement by CEN of this product.

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5.3.2.13 Ultrasonic bath, capable of operating at a frequency 30 kHz to 55 kHz, maximal output

1 000 W.
5.4 Preparation of test organism suspension and product test solutions
5.4.1 Test organism suspension (test and validation suspension)
5.4.1.1 General
NOTE Test and validation suspension are the same in this document.

For each test, one suspension shall be prepared: this is used as the bacterial “test suspension” to perform

the test and the “validation suspension” to perform the controls and method validation.

5.4.1.2 Preservation and stock cultures of test organisms

The test organisms and their stock cultures shall be prepared and kept in accordance with EN 12353.

5.4.1.3 Working culture of test organisms

In order to prepare the working culture of test organisms, prepare a subculture from the stock culture by

streaking onto TSA slopes or plates and incubate. After 18 h to 24 h prepare a second subculture from the

first subculture in the same way and incubate for 18 h to 24 h. From this second subculture, a third

subculture may be produced in the same way. The second and (if produced) third subculture are the

working cultures.

If it is not possible to prepare the second subculture on a particular day, a 48 h subculture may be used

for subsequent sub-culturing, provided that the subculture has been kept in the incubator (5.3.2.3) during

the 48 h period. In these circumstances, prepare a further 24 h subculture before proceeding.

Never produce and use a fourth subculture
5.4.1.4 Test suspension (“N”)

a) Take 10 ml of diluent and place in a 100 ml flask with 5 g of glass beads. Take the working culture

and transfer loopfuls of the cells into the diluent. The cells should be suspended in the diluent by

rubbing the loop against the wet wall of the flask to dislodge the cells before immersing in the diluent.

Shake the flask for 3 min using a mechanical shaker. Aspirate the suspension from the glass beads

and transfer to a tube.
9 9

b) Adjust the number of cells in the suspension to 1,5 × 10 cfu /ml to 5,0 × 10 cfu/ml using diluent,

estimating the number of cfu/ml by any suitable means. Maintain this test suspension in the water

bath at (20 ± 1) °C and use within 2 h. The use of a spectrophotometer for adjusting the number of

cells is highly recommended (about 620 nm wavelength – cuvette 10 mm path length). To achieve

reproducible results of this measurement it may be necessary to dilute the test suspension.

NOTE A colourimeter is a suitable alternative.
−6 −7

c) For counting prepare 10 and 10 dilutions of the test suspension using diluent.

Mix [5.3.2.6 a)].
cfu/ml = colony forming unit per millilitre
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Take a sample of 1,0 ml of each dilution in duplicate and inoculate using the pour plate or the spread plate

technique.

1) When using the pour plate technique, transfer each 1,0 ml sample into separate Petri dishes and add

15 ml to 20 ml melted TSA (5.2.2.3), cooled to (45 ± 1) °C.

2) When using the spread plate technique, spread each 1,0 ml sample – divided into portions of

approximately equal size - on an appropriate number (at least two) of surface dried plates containing

TSA.
For incubation and counting see 5.4.1.5.
5.4.1.5 Incubation and counting of the test suspension

Incubate (5.3.2.3) the plates for 20 h to 24 h. Discard any plates that are not countable (for any reason).

Count the plates and determine the total number of cfu. Incubate the plates for a further 20 h to 24 h. Do

not recount plates that no longer show well-separated colonies. Recount the remaining plates. If the

number has increased, use only the higher number for further evaluation.

Note for each plate the exact number of colonies but record > 330 for any counts higher than 330 and

determine the Vc values according to 5.6.2.2.

Calculate the numbers of cfu per 1 ml in the test suspension N using the formula given in Clause 5.6.1.

NOTE 0,05 ml of an equal parts mixture of the test suspension and interfering substance is added to the surface

therefore 0,025 ml of the suspension is added.
5.4.2 Product test solution

Product test solutions shall be prepared in hard water (5.2.2.6) at a minimum of three different

concentrations to include one concentration in the active range and one concentration in the non-active

range (5.8.2). The product, as received, may be used as one of the product test solutions. Dilutions of

ready-to-use products, i.e. products that are not diluted when applied, shall be prepared in water (5.2.2.2)

instead of hard water.

For solid products, dissolve the product as received by weighing at least 1,0 g ± 10 mg of the product in a

volumetric flask and filling up with hard water (5.2.2.6). Subsequent dilutions (i.e. lower concentrations)

shall be prepared in volumetric flask
...