ICS 67.020  
Price based on …..pages  
Reference number  
DRS 234-2: 2020  
© RSB 2020  
  
 RWANDA 
STANDARD  DRS 
234-2 
 
Second  edition  
Approved by RSB 2020 -mm-dd 
 
Non-food compounds used in food 
processing establishments  — 
Requirements  — 
Part 2: 
Detergents used for cleaning purposes  
   
DRS 234-2: 2020  
i                ©RSB 2020  - All rights reserved  
 In order to match with technological development and to keep continuous progress in industries, 
standards are subject to periodic review. Users shall ascertain that they are in possession of the latest 
edition  
 
 
 
 
 
 
 
 
© RSB 2020  
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized 
in any form or by any means, electronic or mechanical, including photocopying and microfilm, without 
prior written permission from R SB. 
Requests for permission to reprodu ce this document should be addressed to : 
Rwanda Standards  Board  
P.O Box 7099 Kigali -Rwanda  
KK 15 Rd, 49  
Tel. +250 788303492  
Toll Free: 3250  
E-mail: info@rsb.gov.rw  
Website: www.rs b.gov.rw  
ePortal: www.portal.rsb.gov.rw   CD 234 -2: 2020  
©RSB 2020  - All rights reserved                  ii 
 Contents  Page 
1 Scope  ................................ ................................ ................................ ................................ ...................... 1 
2 Normative references  ................................ ................................ ................................ ............................ 1 
3 Terms and definitions  ................................ ................................ ................................ ........................... 1 
4 Classification  ................................ ................................ ................................ ................................ .......... 2 
5 Requirements  ................................ ................................ ................................ ................................ ......... 2 
5.1 General requirements  ................................ ................................ ................................ ............................ 2 
5.2 Specific requirements  ................................ ................................ ................................ ........................... 3 
6 Packaging, labelling and storage  ................................ ................................ ................................ ......... 3 
6.1 Packaging  ................................ ................................ ................................ ................................ ............... 3 
6.2 Labelling  ................................ ................................ ................................ ................................ ................. 3 
6.3 Storage  ................................ ................................ ................................ ................................ .................... 4 
Annex  A (normative)  D etermination of available chlorine  ................................ ................................ ............ 5 
A.1 Reagents  ................................ ................................ ................................ ................................ ................. 5 
A.2 Procedure  ................................ ................................ ................................ ................................ ............... 5 
A.3 Calculation  ................................ ................................ ................................ ................................ .............. 6 
Annex  B (normative )  Determination of the detergent corrosion potential  ................................ .................. 7 
B.1 Apparatus and materials  ................................ ................................ ................................ ....................... 7 
B.2 Pre-cleaning of test panels and rubber bands  ................................ ................................ ................... 7 
B.3 Procedure  ................................ ................................ ................................ ................................ ............... 8 
B.4 Interpretation o f results  ................................ ................................ ................................ ........................ 9 
B.5 Report  ................................ ................................ ................................ ................................ ..................... 9 
 
 DRS 234-2: 2020  
iii                ©RSB 2020  - All rights reserved  
 Foreword  
Rwanda Standard s are prepared  by Technical Committees and approved by R wanda Standards Board (RSB) 
Board  of Directors in  accordance with the procedures of RSB, in compliance with Annex 3 of the World Trade 
Organisation/Technical Barrier to Trade ( WTO/TBT ) agreement on the preparation, adoption and application 
of standards.  
The main task of technical committees is to prepare national standards.  Final Draft Rwanda S tandards 
adopted by Technical committ ees are ratified  by me mbers of RSB Board of Director s for publication and 
gazettment as Rwanda Standards.  
CD 234-2 was prepared by Technical Committee RSB/TC 024, Chemicals and Consumer Products . 
In the preparation of this standard, reference was made to the following standard s: 
1) KS 2117 : Acidic detergents for ‘Cleaning -in-place’ in food and beverage industry — Specification  
2) KS 2119 : Heavy duty alkaline detergents for ‘Cleaning -in-place’ in food and beverage industry — 
Specification  
The assistance de rived from the above source is hereby ack nowledged with thanks.  
This second edition cancels and replaces the first edition (RS  234-2: 2014 ), which has  been technically 
revised.  
DRS  234 consists of the following parts, under the general title Non-food compounds used in food processing 
establishments  — Requirements : 
 Part 1: Food -grade lubricants  
 Part 2: Detergents used for cleaning purposes  
 
Committee membership  
The following organizations were represented on the Technical Committee on Chemicals and Consumer 
Products (RSB/TC 024) in the preparation of this standard.  
Star Construction and Consultancy (SCC) Ltd  
Rwanda Forensic Laboratory (RFL)  
National Industrial Research and Development Agency (NIRDA)  CD 234 -2: 2020  
©RSB 2020  - All rights reserved                  iv 
 University of Rwanda/College of sciences and Technology (UR/CST)  
University of Kibungo (U NIK) 
Ministry of Health (MoH)  
PHARMALAB  
BARANYUZWE Cosmetics Ltd  
Rwanda  Standards Board  (RSB) – Secretariat  DRS 234-2: 2020  
v                ©RSB 2020  - All rights reserved  
 Introduction  
The cleaning agent helps to loosen the contaminating substances and suspend them in the solution so that 
they can be rinsed out with t he cleaning solution. In addition, the cleaning agent must prevent calcium and 
magnesium from forming limescale (limescale is a deposit which mainly consists of calcium and magnesium). 
The cleaning agent may be acidic or alkaline. Alkaline cleaning agents are often the standard type of agent 
used. Acidic cleaning agents are used subsequently, for example once a week, to remove limescale. 
Disinfectants are used to kill bacteria. Disinfectants often consist of chlorine or chlorine compounds. In some 
alternati ve washing systems, disinfection is replaced by high heat.  
 CD 234-2: 2020  
1                ©RSB 2020  - All rights reserved  
 
 Non-food compounds used in food processing establishments  — 
Requirements  — Part 2: Detergents used for cleaning purposes  
1 Scope  
This Committee Draft prescribes specific quality requirements and minimum safety requirements for both 
acidic and alkaline detergents used for cleaning food processing equipment, machinery, piping, et c., made of 
stainless steel in a food processing establishments where such detergents may come in contact with food.  
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.  
RS ISO 4316,  Surface active agents  — Determination of pH of aqueous solution — Potentiometric method  
RS ISO 684, Analysis of soaps — Determination of total free alkali  
ISO 4314, Surface active agents — Determination of free alkalinity or free acidity — Titrimetric method  
RS EAS 814, Determinat ion of the biodegradability of surfactants  
3 Terms and definitions  
For the purposes of this standard, the following terms and definitions apply . 
3.1 
soil 
any residue, scale and other deposits to be removed from the food and beverage contact surface during the 
cleaning process  
3.2 
use dilution  
minimum concentration of the detergent, in water, that the manufacturer has recommended for acid cleaning  
3.3 
Cleaning -In-Place (CIP)  
method for cleaning equipment, using no direct mechanical aid to remove the soil but  depending on solution 
flows, temperature and the properties of the detergent solution   
©RSB 2020  - All rights reserved                  2 
 
 3.4 
use temperature  
temperature that the supplier/manufacturer reco mmends for a specific applicati on. Cold is between 1 ºC and 
35 ºC, warm between 36 ºC and 59 ºC, and hot is 60 ºC and above.  
4 Classification  
The detergents used for cleaning food processing equipment  may be acidic or alkaline , and depending o n 
their application,  they are classified as follows:  
4.1 Acidic detergents — include organic and inorganic a cids. The most common inorganic acids used 
include phosphoric, nitric, sulfamic, sodium acid sulfate, and hydrochloric. Organic acids, such as 
hydroxyacetic, citric, and gluconic, are also in use.  They are often used in a two -step sequential cleaning 
regim e with alkaline detergents.  Acidic detergents are also used for the prevention or removal of stone films 
(mineral stone, beer stone, or milk stone).  
4.2 Alkaline  detergents — Highly alkaline detergents  (or heavy -duty detergents ) use caustic soda (sodium 
hydroxide) or caustic potash (potassium hydroxide). An important property of these detergents is that they 
saponify fats: forming soap . These cleaners are used in many CIP systems or bottle -washing applications. 
Moderately Alkaline Detergents  include sodium,  potas sium, or ammonium salts of phosphates, silicates, or 
carbonates. Tri -sodium phosphate (TSP) is one of the oldest and most effective. Silicates are most often used 
as a cor rosion inhibitor. Because of interaction with calcium and magnesium and film formation, carbonate -
based detergents are of only limited use in food processing cleaning regimes.  
5 Requirements  
5.1 General requirements  
5.1.1 Raw materials used in manufacturing and formulating the detergent shall be suitable for use in a food 
establishment. The detergent shall not contain ingredients which are known to be toxic to humans or form 
toxic by product during or after use.  It may contain chlorine as a disinfecting agent.  
5.1.2 The detergent shall not contain perfume, fragrance or deodorizer. It shal l neither impart any colour, 
odour or flavour to food products; nor leave an objectionable odour to the equipment being cleaned if used in 
accordance with the manufacturer’s instructions.  
5.1.3 The detergent shall be biodegradable when tested in accordance  with RS EAS 814.  
5.1.4 The detergent shall be in liquid or in powder form.  
5.1.5 The detergent in powder form shall be homogenous, off -white colour, free flowing and free form 
foreign matters.  
5.1.6 The detergent in liquid form shall be colourless, clear to light brown liquid.   
3                ©RSB 2020  - All rights reserved  
 5.2 Specific requirements  
5.2.1  The product shall comply with the specific requirements given in table 1 when tested in accordance 
with the methods indicated therein.  
Table 1 – Specific requirements  for detergents used for cleaning purposes  
S/N Parameters  Requirements  Test methods  
Acidic  Alkaline  
Powder  Liquid  
With 
chlorine  Chlorine 
free With 
chlorine  Chlorine 
free 
1 Acidity, % by mass, max.  7.0 — — — — ISO 4314  
2 Alkalinity, % 
by mass, max.  As 
NaOH  — 12 83 40 12 
RS ISO 684  As 
Na2O — 10 65 — — 
3 pH, 1% solution, min.  ≤ 3.5 8 – 13  12 11 12 RS ISO 4316  
4 Available chlorine, % by 
mass, max.  — 2 — 2 — Annex A 
5.2.2  Corrosion  
The detergent shall pass the test when tested in accordance with Annex B at the use -dilution and maximum 
use temperature recommended by the manufacturer.  
5.2.3  Freedom from grit  
A solution of the detergent in powder from prepared at twice the concentration of the use -dilution at the 
recommended temperatu re, using more than 5 g of the product, shall completely dissolve and the solution 
shall be free from grit and residue shall be easily rinseable.  
5.2.4  Alkaline  
The alkaline detergent shall show acceptable cleaning efficacy when used with water of up to 20 0 mg/L 
(expressed as calcium carbonate, CaCO 3) hardness.  
6 Packaging, labelling and storage  
6.1 Packaging  
The product shall be packaged in containers that are strong enough and appropriate to permit normal usage 
and transportation of the detergent, to prevent c ontamination, loss and gain of moisture.  
6.2 Labelling  
Each package shall be legibly, clearly and indelibly labelled with the following information:  
a) Name and nature of the detergent, similar or closely similar to: acidic/alkaline detergent for use in cleaning  
food processing equipment;   
©RSB 2020  - All rights reserved                  4 
 
 b) Manufacturer’s name and physical address including the country of origin;  
c) Net content in SI units;  
d) Batch number;  
e) Date of manufacture and the best before date;  
f) List of ingredients in descending order;  
g) Degree of foaming;  
h) Detailed instructions of use including necessary precautions;  
i) Storage and disposal instructions; and  
j) Available chlorine (or other disinfectants) if claimed.  
6.3 Storage  
The detergent shall be stored in a designated, dry and well -ventilated area which shall be separated from all 
food production, storage and handling areas such that no possibility of cross -contamination of food exists.  
  
5                ©RSB 2020  - All rights reserved  
 Annex  A 
(normative)  
 
Determination of available chlorine  
A.1 Reagents  
A.1.1  Crystalline potassium iodide (iodate free)  
A.1.2  Glacial acetic  acid 
A.1.3  Potassium dichromate solution, 0.1 N  — Carefully pulverize a quantity of potassium dichromate 
(K2Cr2O7) and dry at 110 ºC ± 5 ºC to constant weight. Dissolve 4.7904 g of the dried reagent in water to make 
exactly  1 L and mix thoroughly.  
A.1.4  Standard sodium thiosulphate solution 0.1 N  
A.1.4.1  In a 250 mL glass -stoppered flask, take 2 g of potassium iodide and about 25 mL water to dissolve it. 
Add approximately 2 g of sodium bicarbonate and 5 mL of hydrochloric acid.  
A.1.4.2  Just before the effe rvescence dies down, add 25 mL of 0.1 N potassium dichromate solution. When 
the effervescence ceases, stopper the flask and allow to stand for 10  minutes in a cool dry place.  
A.1.4.3  Dilute with 50 mL of water and titrate against standard sodium thiosulphate solution till the liquid in 
the flask has assumed a yellowish green colour. Add starch solution and continue with the addition of sodium 
thiosulphate solution until the blue colour in just discharged.  
A.1.5  Starch indicator — Titrate 1 g of st arch with 10 mL of cold water and pour, with constant storring, 
into 200 mL of boiling water. Allow to settle and use the clear supernatant liquid.  
A.2 Procedure  
A.2.1  Weigh accurately about 2.5 g  of the sample and grind in a mortar with water till a smooth pa ste is 
formed. Add 15 mL – 25 mL of water and decant off the fine part into a 250 mL flask. Again grind the material 
left behind and repeat the process of decanting off till no gritty material is left. Wash the pestle and monitor in 
the same flask. Make th e solution to 250 mL.  
A.2.2  Take 25 mL of the solution, add 2 g of potassium iodide crystals and 100 mL of water and then add 2 
mL of glacial acetic acid and titrate it against the standardized sodium thiosulphate solution till the pale yellow 
colour is le ft. At this stage add starch indicator and continue the addition of standard sodium thiosulphate 
solution till the blue colour changes.  
  
©RSB 2020  - All rights reserved                  6 
 
 A.3 Calculation  
𝐴𝑣𝑎𝑖𝑙𝑎𝑏𝑙𝑒  𝑐ℎ𝑙𝑜𝑟𝑖𝑛𝑒 ,𝑤𝑡 %=3.5453  𝑥 𝑉 𝑥 𝑁
𝑊 
Where , 
 V volume in mL of the standard sodium thiosulphate solution used;  
 N normality of the standard sodium thiosulphate solution used; and  
 W weight in g of sample t aken for the test, I grams.  
 
   
7                ©RSB 2020  - All rights reserved  
 Annex  B 
(normative)  
 
Determination of the detergent corrosion potential  
B.1 Apparatus and materials  
The following special apparatus and material s are required:  
a) Squat and tall 1 L beakers of Pyrex glass and watch glasses to cover beakers;  
b) A water bath with a close -fitting lid capable of maintain the test temperature (see B.3 (b)) within ± 1 ºC; 
c) An oven capabl e of maintaining a temperature of 105 ºC ± 2 ºC; 
d) Test panels made of stainless steel (316) of approximate dimensions 125 x 63 x 1.5 mm. the panel shall 
have a ‘2B’ finish on both faces. They shall be undamaged and unmarked, flat and their edges free from 
burrs; 
e) Stainless steel tongs for handling the panels;  
f) Panel holders made of inert material such as polypropylene for use during pre -cleaning and drying 
operations;  
g) Rubber bands of rectangular cross -section, measuring, when lying flat and unstretched, approx imately 6 x 
80 mm;  
h) Magnesium carbonate, LR grade, for use as an abrasive for cleaning the panels; and  
i) Distilled water.  
B.2 Pre-cleaning of test panels and rubber bands  
B.2.1  Panels  
The pre -cleaning procedure for panels shall be as follows:  
a) Swab the tes panels, two for each test, with cotton wool using a warm 1 % m/V solution of a general 
purpose dairy detergent;  
b) Scour the panels with cotton wool using water as lubricant and the magnesium carbonate as an abrasive;  
Note  The scouring is to remove any film t hat is produced by reaction between the detergent and the abrasive, e.g. 
magnesium silicate.   
©RSB 2020  - All rights reserved                  8 
 
 c) Without delay, thoroughly rinse the panels under hot tap water;  
d) Rinse the panels I boiling water immersing each panel in turn in water contained in three 1 L beake rs; and  
e) Dry in oven at 105 ºC ± 2 ºC and allow to cool in a dry, dust -free position.  
B.2.2  Rubber bands  
The pre -cleaning procedure for rubber bands shall be as follows:  
a) Place the rubber bands in a hard -boiling 1% m/V solution of general purpose dairy deter gent; and  
b) Rinse under hot tap water and then rinse in distilled water and allow to dry.  
B.3 Procedure  
The procedure shall be carried out in duplicate as follows:  
a) In a tall 1 L beaker, make up 950 mL of the use dilution of the detergent under test, mark the lev el of the 
solution on the side of the beaker;  
b) Heat the solution to the maximum use temperature recommended b y the manufacturer ; 
c) Place the beaker of solution in a water bath controlled at the maximum use temperature ± 1 ºC; 
d) Place a rubber band around the te st panel in the direction of the panel’s long axis, ensuring that the band 
is fat against both sides of the panel and that the panel is not touched by fingers;  
e) 5 minutes after placement of the band, immerse the panel on its end in the test solution so that  there is at 
least 10 mm of solution above the panel. Note the time;  
f) Leave the panel in the test solution for 72 hours. Each morning and evening, top up the solution to the 
mark with distilled water;  
g) At the end of the 72 hours, remove the panel from the te st solution and remove the rubber bands and 
rinse under hot, running tap water;  
h) Rinse three times as prescribed in paragraph B.2.1 (c) above;  
i) Final, dry the panel in the oven at 105 ºC. allow to cool; and  
j) Examine the panel for evidence of corrosion (see no te below); or discoloration.  
Note  Pitting is most likely to occur where the rubber band contacts the edges of the panel.   
9                ©RSB 2020  - All rights reserved  
 B.4 Interpretation of results  
If the duplicate panels from the test detergent show the same characteristics, record the result. If the 
duplicates differ, repeat the test using fresh panels.  
B.5 Report  
The report shall contain the information, whether corrosion or discoloration of the panels has occurred.   
©RSB 2020  - All rights reserved                  10 
 
 Bibliography  
[1] ISO/IEC Directives, Part  2, Rules for the structure and drafting of Inte rnational Standards , 2016  
[2] ISO/IEC  TR 10000 -1, Information technology  — Framework and taxonomy of International 
Standardized Profiles  — Part 1: General principles and documentation framework  
[3] ISO 10241  (All parts) , Terminological entries in standards