KENYA STANDARD                    KS 03-929: 2009 
                         ICS 67.160.20  
 
 
 
 
 
 
 
 
Specification for QAC based aromatic 
disinfectant liquid  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
No copying of this standard without KEBS permission  except as permitted by copyright law    
 TECHNICAL COMMITTEE REPRESENTATION 
 
 
The following organizations were represented on the  Technical Committee:  
Haco Industries LTD 
Consumer Information Network 
Kel Chemicals 
University Of Nairobi 
KIRDI 
Jet Chemicals 
Reckitt Benkiser 
Kenya Bureau of Standards — Secretariat 
 
 
 
REVISION OF KENYA STANDARDS 
 
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improvements to published standards, addressed to t he  Managing  Director, Kenya Bureau of Standards, are 
welcome. 
 
 
 
 
 
 
© Kenya Bureau of Standards, 2009 
 
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ISBN 9966-23-619-8 
 KENYA STANDARD                           KS 03-929: 2009 
                         ICS 67.160.20  
 
 
 
 
 
 
 
 
Specification for QAC based aromatic 
disinfectant liquid  
 
 
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
KENYA BUREAU OF STANDARDS (KEBS) 
 
Head Office:  P.O. Box 54974, Nairobi-00200, Tel.: (+254  020) 60 5490, 602350, Fax: (+254 020)  604031 
E-Mail: info@kebs.org,  Web:http://www.kebs.org   
 
Coast Region    Lake Region         North Rift Regi on  
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Fax: (+254  041) 229448   Fax: (+254 057) 21814              
 
 
 KS 03-929: 2009                                                                                                    ©KEBS 
2  
P R E F A C E 
 
This Kenya Standard was prepared by the Technical C ommittee on Disinfectants, under the guidance of th e 
Chemical Industry Standards Committee, and it is in  accordance with the procedures of the Bureau. 
QAC based aromatic disinfectant fluids are aromatic  disinfectant fluids containing quaternary ammonium  
compounds as their principle antmicrobial agents. T he quaternary ammonium compounds are water soluble.  
Disinfectant fluids are used for the destruction of  micro-organisms, but not usually bacterial spores.  They do not 
necessarily kill micro-organisms, but reduce them t o levels, which are not harmful to health or the qu ality of 
perishable goods. 
This standard covers five grades of QAC based aroma tic disinfectant fluids which are designated accord ing to 
their antimicrobial activity. This characteristics of disinfectants are very important to the user, th us the need for a 
standard. The test method included in this standard , counts the, number  of  viable  organisms  before   and after 
the disinfecting process has been completed. In add ition to antimicrobial value, the standard also spe cifies 
general composition, pH, stability and staining. 
 
These QAC based aromatic disinfectants are used in households and domestic service disinfecting. 
 
During the preparation of this standard, reference was made to the following documents 
 
BS 6424: 1984   Specification for QAC based aromati c disinfectant fluids.  
 
BS 6471: 1984   Method for determination of the ant imicrobial value of QAC disinfectant formulation. 
 
NS 5197: 1976   Specification for aromatic disinfec tant fluids. 
 
The assistance obtained from the above documents is  acknowledged with thanks. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
3  
KENYA STANDARD 
 
SPECIFICATION FOR QAC BASED AROMATIC DISINFECTANT L IQUID  
 
 
1. SCOPE 
 
This Kenya Standard specifies requirements for five  grades of light-duty, aromatic disinfectant fluids  
containing quaternary ammonium compounds (QACs) as their principal antimicrobial agents.  The five 
grades are designated according to their antimicrob ial activity, as measured by the method described i n 
Appendix A. 
 
2. APPLICATION  
 
This standard applies to disinfectants used in hous eholds and public institutions such as schools, hot els 
and hospitals. 
 
3.  GRADE DESIGNATION 
 
 For a fluid to be designated as one of the followin g grades, it shall have an antimicrobial value, whe n 
determined by the method described in Appendix A no t less than the value given below for the grades 
concerned. 
 
 
   Grade     Minimum Antimicrobial Value  
   
   QAP 30        30 
   QAP 50       50 
  QAP 100     100 
  QAP 200     200 
  QAP 300     300 
   
4.  REQUIREMENTS  
 
4.1  General Composition — The fluids shall either be clear solutions or homog eneous suspensions 
containing one or more QACs which largely confer th e disinfectant properties. They shall contain pine 
oil, related tarpenes or other compatible odour-enh ancing compounds. 
 
They may also contain non-ionic surfactants or othe r builders and solubilizers, which, if used, shall not 
affect adversely either the activity of the disinfe ctant or the packaging.  
  
4.2 Stability Before Dilution   
 
4.2.1  Normal Storage Stability  — After two separate samples have been stored for 3 m onths in accordance 
with the method described in Appendix B, at 10 ± 2° C and 35 ± 2°C respectively, neither shall show any  
precipitate of solid matter or any separation into layers, and there shall be not a decrease in 
antimicrobial value to below the minimum specified in 3 for the grade concerned. 
 
4.2.2 Cold Storage Stability — The fluids shall remain homogeneous after standing at 0°C to 1°C for 6 h in 
accordance with the method described in Appendix B.  
4.2.3 Hot Storage  Stability — The fluids shall remain homogeneous after standing at 40°C for 6 h in 
accordance with the method described in Appendix B.  
 KS 03-929: 2009                                                                                                    ©KEBS 
4 4.3 Stability after Dilution  —  Solutions of fluids in the standard hard water p repared shall be 
homogeneous at all dilutions down to that correspon ding to twice the minimum antimicrobial value 
specified in 3, for the grade concerned, and there shall be not any  separation into layers after two 
separate such dilutions have been left standing for  6 h at 10 ± 2°C and 35 ± 2°C, respectively. 
 
Standard hard water is prepared by dissolving 0.304  g of anhydrous calcium chloride (CaCl 2) and 0.139 
magnesium chloride hexahydrate (MgC1 2.6H 20) in water and dilution water to the mark in a 100 6 mL  
one-mark volumetric flask. The hardness corresponds  to 342 mg/L of hardness, calculated as CaCO 3. 
 
4.4 Staining — If the fluid is recommended for use on fabrics, the n the change in the whiteness value of 
the test fabric when tested according to Appendix C , shall not exceed 7 per cent of the whiteness valu e 
of the control sample. 
 
4.5 Packaging — The fluids shall be packed in containers so that they can be stored at both 10 ± 2°C and 
at 35 ± 2°C for 12 months without any interaction b etween the container and the fluid that will bring the 
later outside the above requirement. 
 
4.6  Marking —Each container of fluid or a label firmly attached  to each container shall be marked legibly 
and indelibly with the following information:  
 
(i)  Name and address of manufacturer /distributor and registered trade mark, if any; 
  
(ii) Batch or code number; 
  
(iii) Net volume of contents; 
  
(iv) The words QAC aromatic disinfectant giving its  QAP value and active ingredient used. 
  
(v) Date of manufacture and expiry date; 
  
(vi) Recommendations for use in fabrics, if appropr iate 
  
(vii) Country of origin.       Instructions for use , given in the imperative tense, including at least  the 
dilutions recommended for particular applications a nd that the dilutions should be freely and 
accurately prepared in clean containers, together w ith the following:  
 (a) Either an indication that the main use of the fluid is to disinfect articles that are visibly cle an or 
only lightly soiled. 
  
 (b)  That heavily-soiled articles should be rinsed  clean before being disinfected. 
(c)A statement that no recommendation is made for u se for disinfecting purposes at dilutions greater 
than that corresponding to the antimicrobial value.  
 
(d)An instruction not to mix with soaps, anionic su rfactants, acids and organic matter. 
 
(e)  Both date of manufacture and date of expiry to gether with the batch number. 
 
(f)  ‘Keep away from children’.  
 
(g)  'ONLY FOR EXTERNAL USE' should be clearly labe lled in capital letters together with ‘In case  
of accidental ingestion, take milk and seek medical  attention immediately’. 
 
 
 
 
 
 
 
 
  
5  
 
 
A P P E N D I X    A 
 
DETERMINATION OF THE ANTIMICROBIAL VALUE OF QAC DIS INFECTANT 
FORMULATIONS 
 
A1. PRINCIPLE OF THE METHOD 
 
 A  challenge  medium  is  added  to  a  series of  dilutions of  a product  and,  after  a  contact  p eriod  of  
 600 ± 5 s at 22 ± 0.5°C, the mixture de-activated.  Serial tenfold dilutions of the de-activated mixtu re are 
then incubated on pour plates a fixed time and the colonies counted. The procedure is repeated, as 
necessary until two dilutions differing in concentr ation by a ratio of 2:3 are obtained, one of which 
returns a colony count not greater than 0.01 per ce nt (i.e., 99.99 per cent 'Kill') of that returned b y a 
control not containing the product and the other of  which returns a colony count greater than 0.01 per  
cent of that returned by a control not containing t he product. 
 
A2. STERILIZATION 
Wherever sterile reagents, media, material or appar atus are referred to, or an instruction to steriliz e 
them appears, the sterility shall be achieved by be ing kept at either: 
  
(i) 170°C to 175°C for not less than 1 h in an oven  (dry sterilization); or  
 
(ii) 121 ± 1°C for 15  min in an autoclave (wet ste rilization).  
 
Manipulation of sterile material and bacterial cult ures shall be carried out aseptically.  
 
A3.  REAGENTS AND MATERIALS 
A3.1  General — All reagents shall be of recognized biological or  analytical grade and distilled water. All 
solutions and media shall be freshly prepared.  
 
A3.2  Diluent — Dissolve 10.0 g of calcium chloride hexahydrate ( CaCI 2.6H 20) in water and  dilute to 100 mL. 
Dissolve 10.0g of Magnesium sulphate heptalydrate  (MgSO 2.7H 2O) in water and dilute to 100 mL.  Add 
3.5 mL of the calcium chloride solution and  1.0 mL  of the magnesium sulphate solution to 
approximately 500 mL of water in 1L volumetric flas k and dilute to the mark with water.  This diluent 
corresponds to a synthetic hard water of 200 ± 10 m g/kg hardness. 
 
A3.3 Test Organism — Escherichia coli, ATCC 11229. 
A3.4 Solid Culture Medium  —  Oxoid  nutrient agar CM3 sterilized in accordance with A2. 
A3.5 Liquid Culture Medium — Standard strength, oxoid nutrient broth No. 2 ster ilized in accordance with 
A2. 
A3.6  Inactivator — Add  2 g of Soya lecithin and 3 g of between 80 to 95 mL  of water, warm to 50°C to 60°C 
and stir until no visible lumps remain and the susp ension is evenly opalescent. Dispense into capped 
containers in 9 mL quantities and sterilize in acco rdance with A2. 
A3.7  Ringer's Solution — Quarter-strength — Dissolve 9.00 g of sodium chloride, 0.42 g of potas sium 
chloride, 0.24 g of anhydrous calcium chloride and 0.20 g of sodium hydrogen carbonate in water and 
dilute to 100 mL. 
 
Add 1 volume of this solution to 3 volumes of water  to give a quarter-strength solution. Dispense into  
150/16 mm test tubes fitted with suitable colours a nd sterilize in accordance with A2. Ringer's solution 
tablets may also be used. Dissolve 1 tablet in the appropriate volume of water to obtain a quarter-
strength solution, fill 150/16 mm test tubes fitted  with suitable closures and sterilize according to A2. 
 
 KS 03-929: 2009                                                                                                    ©KEBS 
6  
 
 
A3.8  Horse Serum Oxide SR 35 
 
A3.9   Check disinfectant, clodecyldimethyl-s-phenoxyeth yl ammonium bromide, 75 mg/L and 125 mg/L 
solutions. 
 
A4.  APPARATUS 
 
A4.1  Ordinary microbiological laboratory apparatus espec ially as given below: 
 
A4.1.1 2 mL pipettes  
A4.1.2  Universal container culture bottles, 28 mL capacity  
A4.1.3  Petri dishes  
A4.1.4  Water bath , capable of being controlled at 22 ± 1 °C.  
A4.2  Cleanliness —   Special care in the use and cleaning of glassware  is necessary because of the strongly 
absorptive properties of QAC. The following cleanin g procedure should be followed: 
 
Wash glassware in cold 62 g/L nitric acid solutions  and allow to stand overnight in the acid. Rinse 
successively with 4 g/L sodium hydroxide solution, tap water, 6 g/L nitric acid solution and tap water  
until the acid is removed. Finally, rinse with dist illed water. 
 
A5.  PREPARATION OF TEST CULTURE 
A5.1 Initial Culture —  The test organism ( A3.3 ) is distributed in tubes in freeze-dried form, and s hall be 
reconstituted in accordance with the supplier's ins tructions. 
 
Using a sterilized pipette, add approximately 0.5 m L of the sterilized liquid culture medium ( A3.5 ) to the 
contents of the tube and incubate for 25 hours at 3 7 ± 1°C. From this initial culture, prepare the sto ck 
culture (A5.2 ) and, from that, the broth cultures ( A5.3 ). 
 
A5.2  Stock Culture —  Spread a loopful of the initial culture over the s urface of a 'slope' of the sterilized solid 
culture medium ( A3.4 ). 
 
Incubate for 24 h at 37 ± 1°C and store at not abov e 22°C, and preferably between 4°C and 10°C, until 
required. Stock cultures so stored  should  be  use d within 1 month,  although  sub-cultures can  be 
 taken before the expiry of that date. Not more tha n six serial sub-cultures shall, however, be taken 
before resorting to a new freeze-dried tube ( A3.3 ). 
 
A5.3   Broth Culture —  Inoculate a tube of 10 mL of the liquid culture me dium (A3.5 ) from the stock culture, 
(A5.2 ) and incubate at 37 ± 1°C for 22 h to 26 h.  Progres sively sub-culture into fresh liquid culture 
medium every 24 h, incubating the inoculum at 37 ±  1°C for 22 h to 26 h and use sub-culture 2 to 6 fo r 
the preparation of the challenge medium ( A6 ).  After six broth-to-broth sub-cultures, restart the process 
using fresh stock culture.  
A6. PREPARATION OF CHALLENGE MEDIUM 
From the broth culture ( A5.3 ) prepare aseptically a challenge medium according to  the following 
formula: 
(i)  broth culture ( A5.3 ):  2 paits by volume.  
(ii) horse serum ( A3.8 ):  5 paits by volume.  
(iii)  diluent ( A3.2 ):  3 paits by volume. 
  
7  
 
Hold at 22°C for not more than 4 h.  The challenge  medium  so  prepared  should  contain between 5 x 
10 7 and 5 x 10 8 colony-forming units per millilitre, measured as d escribed in A8 . 
 
A7 .  PREPARATION OF DILUTIONS 
 
A7.1  General — Dilutions of the product shall be prepared volumetr ically by pipette and sufficiently over-
strength to allow the further dilution when the 1 m L of challenge medium is added. For example, 
prepare a 1:100 dilution at 1:90. 
 
Prepare all dilutions in the diluent ( A3.2 ) and include two containers of 9 mL of the diluent a lone in each 
series carried out at the same time, to function as  controls. 
 
Place 9 mL  of each dilution  in  sterile  universa l  container  culture  bottles and  hold  in  a  wa terbath 
at 22 ± 0.5°C until equilibrated at that temperatur e. 
 All dilutions shall be prepared and tested in the same working day. 
 A7.2  Range of Dilutions 
 
A7.2.1 If  t he  potency  of  the  product  is   known  ap proximately,  prepare   three   dilutions  of   con centration  
3 x /2, x,  2 x /3, respectively, where x is the co ncentration that  is  expected to return a colony  count  of  
about 0.01 per cent of that returned by the control . If a satisfactory result is not obtained using th is 
choice of dilutions, proceed to a more appropriate choice. 
 
A7.2.2 If the product has a completely unknown potency, ca rry out a preliminary test on a series of widely- 
ranged dilutions, such as 1:5, 1:25 and 1:125, and repeat the test on successively narrow ranges until  
the aim of the test is achieved. 
 
A7.2.3 If the potency is known only in terms of QAC conten t, carry out a preliminary test on dilutions equiva lent  
to 300 mg/L, 200 mg/L and 100 mg/L, and then repeat  the procedure as described in A7.2.2 until the 
aim of the test is achieved. 
 
A8.  TEST PROCEDURE 
A8.1 At time 0, pipette 1 mL of the challenge medium ( A6 ) into 9 mL of each of the dilutions ( A7.1 ) under test 
in both of the 9 mL portions of the control diluent  (A7.1 ) and mix by gentle rotation. Ensure that every 
trace of challenge medium is brought into full cont act with the disinfectant but avoid foam formation.  
Maintain at 22 ± 0.5°C until the end of the contact  period of 600 ± 0.5 s and shortly before the end o f 
this contact period, repeat the mixing. 
 
A8.2  At time 0 + (600 ± 5) s, deposit 1 mL of the mixtur e into 9 ml of the inactivator and mix the contents  by 
shaking. 
A8.3 Within 1 h of inactivation, make serial decimal dil utions in the Ringer's solution ( A3.7 ).,Prepare delicate 
pour plates from 1 mL of these dilutions and 10 mL of the sterilized solid culture medium ( A3.4 ) after the 
latter has been melted and equilibrated at 45°C. Al low to set, invert the plates and incubate at 37 ± 1 °C 
in the inverted position for 48 ± 2 h and then coun t the colonies. 
 
A9. TEST RESULT 
 
After appropriate calculation, record the antimicro bial value as the greatest dilution of the product,  in the 
volume by volume terms (or in mass by volume terms in the case of solid or very viscous products), tha t 
returns a colony count not greater than 0.01 per ce nt average of the colony count returned by the two 
diluent controls. 
 
For example, if the greatest such dilution is 1:100 , the antimicrobial value is 100. 
 
If there has been a significant reduction in the nu mber of viable cells in the controls during the tes t 
period, repeat the test  KS 03-929: 2009                                                                                                    ©KEBS 
8   
 A P P E N D I X     B 
METHOD OF TEST FOR STABILITY BEFORE DILUTION  
 
Store the samples in round, narrow necked, clear bo ttles of 250 mL to 300 mL capacity, fitted with 
screw caps with ment liners. Ensure that the ullage  does not exceed 5 per cent and that the samples 
are protected from direct sunlight and from localiz ed overheating and overcooling during the storage 
period. 
 
 
 
 
 
 
 
A P P E N D I X    C 
 
STAINING TEST FOR AROMATIC DISINFECTANT FLUIDS 
C1.  MATERIALS 
 
C1.1  Test Fabrics —  The fabric for the test shall be bleached cotton l awn free from filling and from 
fluorescent brightening agents. The fluidity shall be not greater than 4.00. The weight shall be 94 gm2. 
  
 Six pieces of fabric, 30 cm  x  15 cm, are  requir ed, three  for  each test with the  disinfectant  f luids  and 
three to serve as controls. 
C1.2  Disinfectant Dilutions —  Use a dilution factor equal to one  in  10  times  the  claimed  Rideal-Walker  
coefficient or antimiziobial value in this case. Fo r dilution use distilled water. 
 
C2.  PROCEDURE 
 
C2.1  Treatment of Test Pieces —  Form each piece of a test fabric into a loose coil  that can be suspended 
vertically in a beaker or similar vessel. Using a s eparate portion of the diluted fluid for each piece  of 
fabric, immerse the three pieces in the diluted dis infectant fluid and leave at room temperature for 6  h. 
 
 At the end of 6 h squeeze each test piece by hand and transfer it to 500 mL of water (distilled water ). 
Using a glass rod, stir the piece gently for 1 min,  then discard the water and repeat the rinsing in a  
further 500 mL of water. Remove the piece from the water, squeeze it by hand and hang it lengthwise in  
air to dry. 
 
Do not allow the pieces to become so dry that they are difficult to iron flat. 
Iron the test pieces, preferably with a steam iron,  but otherwise with a domestic electric iron fitted  with a 
thermostatic control. Set the control just below t a setting for cotton. Remove all creases from the t est 
pieces. 
 
C2.2  Control Pieces —  Treat the three control pieces in exactly the same  manner as the test pieces but use 
distilled water instead of the diluted disinfectant  fluid. 
 
C2.3  Visual Assessment of Staining — Place the test pieces and the controls in separate piles, folded to 
give six thicknesses of fabric. Examine the two pie ces side by side, in a good natural light and away 
from coloured reflecting surfaces, and note whether  or not there is a visible difference in colour. 
Examine both sides of each piece of fabric. 
 
 
  
9  
C2.4   Measurement of Staining (for Reference Purposes)   — Place the three test pieces, folded to give a 
total of six thicknesses of fabric, in a single pil e, and measure the reflective value by means of a 
photoelectric reflectometer, using white light. Mak e four measurements on each side of each of the 
three test pieces. Repeat this procedure with the c ontrol pieces. For each set of pieces, calculate th e 
mean of all the readings and record this as the whi teness value. 
 
C3.  CALCULATION OF RESULT (REFEREE METHOD)   
 
 Calculate the loss of whiteness due to the disinfe ctant by means of the following formula: 
 
 Loss of whiteness (1 per cent)    100 
121 x RRR− 
 
where, 
 
R1  =   the whiteness value for control pieces, 
 
R2   =   the whiteness value for fabric treated with dis infectant.