BS/EN 1276-2019 pdf download.Chemical disinfectants and antiseptics — Quantitative suspension test for the evaluation of bactericidal activity of chemical disinfectants and antiseptics used in food, industrial, domestic and institutional areas — Test method and requirements (phase 2, step 1).
b) At the end of this time, take a sample of 1,0 ml of this mixture “8” in duplicate and inoculate using the pour plate or the spread plate technique (5.5.2.2 b)).
For incubation and counting, see 5.5.2.6.
5.5.2.5 Method validation C – dilution-neutralization validation
To validate the dilution neutralization method, the procedure Is as follows.
a) Pipette 1,0 ml of the interfering substance used in the test (5.5.2.2) into a tube. Add 1,0 nil of the diluent (5.2.2.4) and then, starting a stopwatch, add 8,0 ml of the product test solution only of the highest concentration used in the test (5.5.2.2). Mix (5.3.2.6 a)) and place the tube in a water bath controlled at the chosen temperature (9± 1) °C for t. Just before the end of C, mix (5.3.2.6 a)) again.
b) At the end of t transfer 1,0 ml of the mixture into a tube containing 8,0 ml of neutralizer (used in 5.5.2.2). Restart the stopwatch immediately at the beginning of the addition. Mix (5.3.2.6 a)) and place the tube in a water bath controlled at the chosen temperature (8 ± 1) °C for 5 mm ± lOs ((10 ± 1) s for contact times equal or shorter than 10 mm). Add 1.0 ml of the validation suspension (5.4.1.5). Start a stopwatch at the beginning of the addition and mix (5.3.2.6 a)). Place the tube in a water bath controlled at (20 ± 1) °C for (30 ± 1) mm. lust before the end of this time, mix (5.3.2.6 a)) again. At the end of this time, take a sample of 1,0 ml of the mixture C” in duplicate and inoculate using the pour plate or the spread plate technique (5.5.2.2 b)).
For incubation and counting, see 5.5.2.6.
5.5.2.6 Incubation and counting of the test mixture and the control and validation mixtures
For incubation and counting of the test mixture and the control and validation mixtures, the procedure is as follows.
a) 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 cfu on the plates to determine the total number of colony forming units. Incubate the plates for a further 20 h to 24 Ii. 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.
b) 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.
c) Calculate the numbers of cfu/ml in the test mixture “Na” and in the validation mixtures “A”. “H” and C using the method given in 5.6.2.4 and 5.6.2.6. Verify according to 5.7.
5.5.3.1 General
The test and the control and validation procedures (5.5.3.2 through 5.5.3.5) shall be carried out in parallel and separately for each experimental condition (5.5.1.1).
Each membrane filtration apparatus shall be equipped with a membrane of 0.45 pm pore size and 47 mm to 50 mm diameter (5.3.2.7) and filled with 50 ml of the rinsing liquid (5.2.2.6). The time required for filtering — if longer than one minute in exceptional cases — shall be recorded in the test report. When transfemng the membranes to the surface of an agar plate, care should be taken to ensure that the test organisms are on the upper side of the membrane when placed on the plate, and to avoid trapping air between the membrane and agar surface.
5.5.3.2 Test mNa – determination of the bactericidal concentrations
The procedure for determining the bactericidal concentrations is as follows:
a) See 5.5.2.2 a).
b) At the end of t, take a sample of 0,1 ml of the test mixture NNa in duplicate and transfer each 0,1 ml sample into a separate membrane filtration apparatus (5.5.3.1). Filter immediately. Filter through at least 150 ml hut no more than 500 ml of rinsing liquid (5.2.2.6). If the rinsing liquid is not water, complete the procedure by filtering 50 ml of water (5.2.2.2). Then transfer each of the membranes to the surface of separate TSA plates.
For handwash products at the end of t take a sample of 0.1 ml of the test mixture Na and dilute in 100-fold with 9,9 ml of rinsing liquid (5.2.2.6). Mix and transfer 0,1 ml sample in duplicate into two separate membrane filtration apparatus (5.5.3.1). Filter immediately. Filter through at least 150 ml but no more than 500 ml of rinsing liquid (5.2.2.6). lIthe rinsing liquid is not water, complete the procedure by filtering 50 ml of water (5.2.2.2). Then transfer each of the membranes to the surface of separate TSA plates. Validation of non-toxicity of the neutralizing agent shall be performed according to 5.5.3.4 for handwash products.
For incubation and counting, see 5.5.3.6.
c) See 5.5.2.2 c).
d) See 5.5.2.2 d).
5.5.3.3 Experimental conditions control “A — validation of the selected experimental conditions and/or verification of the absence of any lethal effect in the test conditions
To validate the selected experimental conditions and/or verify the absence of any lethal effect In the test conditions, the procedure is as follows:BS/EN 1276-2019 pdf download.
BS/EN 1276-2019 pdf download
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