Reference number  
DRS 51:2017  
© RSB 2017  
 
 
 RWANDA 
STANDARD  DRS 
51 
 
Third  edition  
2017 -mm-dd 
 
Butter — Specification  
 
  DRS 51:2017  
©RSB 2017 - All rights reserved                  ii 
 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 2017  
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. +250 252 586103/ 582945  
Toll Free: 3250  
E-mail: info@rsb.gov.rw  
Website: www.rsb.gov.rw  DRS 51:2017  
iii                ©RSB 2017 - All rights reserved  
 Contents  Page 
1 Scope  ................................ ................................ ................................ ................................ .............  1 
2 Normative references  ................................ ................................ ................................ ...................  1 
3 Term s and definitions  ................................ ................................ ................................ ..................  2 
4 Requirements  ................................ ................................ ................................ ................................  3 
4.1 Raw Materials  ................................ ................................ ................................ ................................  3 
4.2 Permitte d Ingredients ................................ ................................ ................................ ...................  3 
4.3 General requirements  ................................ ................................ ................................ ..................  3 
4.4 Specific requirements  ................................ ................................ ................................ ..................  3 
4.5 Microbiology requirements  ................................ ................................ ................................ .........  4 
5 Food additives  ................................ ................................ ................................ ..............................  4 
6 Contaminants  ................................ ................................ ................................ ................................  4 
6.1 Heavy metals  ................................ ................................ ................................ ................................ . 4 
6.2 Pesticid e and veterinary drug residues  ................................ ................................ .....................  4 
6.3 Aflatoxins  ................................ ................................ ................................ ................................ ...... 5 
7 Hygiene  ................................ ................................ ................................ ................................ ..........  5 
8 Packaging  ................................ ................................ ................................ ................................ ...... 5 
9 Labelling  ................................ ................................ ................................ ................................ ........  5 
10 Sampling  ................................ ................................ ................................ ................................ ....... 2 
 DRS 51:2017  
©RSB 2017 - All rights reserved                  iv 
 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 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 ratifie d by me mbers of RSB Board of Director s for publication and gazettment as 
Rwanda Standards.  
RS 51 was prepared by Technical Committee RSB/TC 004, Milk and milk products.  
In the preparation of this standard, reference was made to the following standard  (s): 
1) SAZS 798:2003, Butter -Specification  
2) KS 05 -27, Butter –Specification  
The assistance de rived from the above source is hereby acknowledged with thanks.  
This third edition  cancels and replaces the second  edition (RS  51:2012 ), which has been  technically revised.  
Committee membership  
The following organizations were represented on the Technical Committee on Milk and milk products  (RSB/TC 
004) in the preparation of this standard.  
Enterprise Urwibutso  
Fromagerie Ikambere  
Fromagerie La Reine  
Global Trading Impex Serena Nice Cream (GTI)  
Inyange Industries  
Laiterie Nyabisindu  
Ministry of Agriculture (MINAGRI/RALIS)  
Rubilizi Dairy  
Agashinguracumu Ltd  DRS 51:2017  
©RSB 2017 - All rights reserved                  ii 
 Rwanda Consumer’s Rights Protection Organization (ADECOR)  
Rwanda National Dairy Platform (RNDP)  
Rwanda  Standards Board (RSB) – Secretariat  
  DRS 51: 2017  
1                ©RSB 2017 - All rights reserved  
 Butter  — Specification  
1 Scope  
This Standard specifies  the requirements , sampling and test methods for butter intended for direct consumption 
or for further processing.  
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 docu ment.  For dated references, only the edition  cited applies. For undated references, the 
latest edition of the referenced document (including any amendments) applies.  
AOAC 999.10, Lead, Cadmium, Copper, Iron, and Zinc in foods, Atomic Absorption Spectrophot ometry after 
dry ashing  
AOAC 999.11, Determination of Lead, Cadmium, Copper, Iron, and Zinc in Foods  
CODEX STAN 193, General standard for contaminants and toxins in foods  
ISO 11813, Milk and milk products -- Determination of zinc content -- Flame atomic absorption spectrometric 
method  
ISO 14501, Milk and milk powder -- Determination of aflatoxin M1 content -- Clean -up by immunoaffinity 
chromatography and determination by high -performance liquid chromatography  
RS CAC/RCP 1, Code of Practice -General princip les of Food Hygiene  
RS CODEX STAN 192, Codex general standard for food additives  
RS EAS 12, Potable water — Specification  
RS EAS 35, Fortified food grade salt — Specification  
RS EAS 38, General standard for the labeling of pre -packaged foods.  
RS ISO 11866 -2, Milk and milk Products -Enumeration of presumptive Escherichia coli -part 2: colony -count 
technique at 44oC using membranes  
RS ISO 1738, Butter –determination of salt content  
RS ISO 3657 , Animal and vegetable fats and oils -- Determination of saponificati on value   
©RSB 2017 - All rights reserved                  2 
 RS ISO 3727 -1 Butter — Determination of moisture, non-fat solids and fat contents —Part 1: Determination of 
moisture content (Reference method)  
RS ISO 3727 -2 Butter — Determination of moisture, non-fat solids and fat contents —Part 2:  Determinatio n of 
non-fat solids content (Reference method)  
RS ISO 660,  Animal and vegetable fats and oils —Determination of acid value and acidity  
RS ISO 3727 -3, Butter — Determination of moisture, non -fat solids and fat contents —Part 3: Calculation of fat 
content  
RS ISO 4833 -1, Microbiology of the food chain —Horizontal method for the enumeration of microorganisms —
Part 1:  Colony count at 30 °C by the pour plate technique  
RS ISO 5738, Milk and milk products -- Determination of copper content -- Photometric method (Reference 
method)  
RS ISO 6579 -1, Microbiology of the food chain -- Horizontal method for the detection, enumeration and 
serotyping of Salmonella -- Part 1: Detection of Salmonella spp.  
RS ISO 6611 , Milk and milk products - Methods of microbiological examin ation part 3: Enumeration of colony 
forming units of yeasts and/or moulds -colony -count technique at 25  
RS ISO 6732, Milk and milk products -- Determination of iron content -- Spectrometric method (Reference 
method)  
RS ISO 707, Milk and milk products — Guid ance on sampling  
RS ISO 7238 , Butter -- Determination of pH of the serum -- Potentiometric method  
RS ISO 1740 , Milk fat products and butter determination of fatty acidity (reference method)  
RS ISO 6320 , Animal and vegetable fats and oils -- Determination o f refractive index  
RS ISO 3961,  Animal and vegetable fats and oils -- Determination of iodine value  
3 Terms and definitions  
For the purp oses of this standard, the follow ing terms and definitions apply . 
3.1 
butter  
fatty product derived exclusively from milk and products obtained from milk, principally in the form of an emulsion 
of the type water -in-oil. DRS 51: 2017  
3                ©RSB 2017 - All rights reserved  
 4 Requirements  
4.1 Raw Materials  
Milk and products obtained from milk.  
4.2 Permitted Ingredients  
The following ingredients shall be used in the manufacture of butter:  
a) Sodium chloride (Edible salt complying with RS EAS 35 ). 
b) Starter cultures of harmless lactic acid and/or flavour producing bacteria  
c) Potable water complying with RS EAS 12.  
4.3 General requirements  
Butter shall be:  
d) free from off flavours and off odours;  
e) free f rom foreign matter; and  
f) free from insects, worms, fungal infestation, rodent contaminations  
4.4 Specific requirements  
Products covered by the provisions of this standard shall comply with the specific requirements  in Table 1  
Table 1 ▬ Specific requirements of  butter  
S/N Characteristics  Requirement  Test method  
i.  Milk fat content, %  m/m , min.  80  RS ISO 3727 -3  
ii.  Milk solids -not-fat content, %  m/m, max.  2  RS ISO 3727 -2 
iii.  Moisture Content, %  m/m ,max   16  RS ISO 3727 -1 
iv.  Salt content as NaCl, %  m/m ,max.   2  RS ISO 1738  
v.  Butter serum pH  6.6-7.0 RS ISO 7238  
vi.  Acid value of fat, %  max 0.10  RS ISO 660  
vii.  Reichert -
Polenske’values  Reichert value  20-35  
RS ISO 1740  viii.  Polenski value  1-3.5 
ix.  Kirschner values  20-33 
x.  Iodine value  26-40 RS ISO 3961   
©RSB 2017 - All rights reserved                  4 
 xi.  Saponification  value  219-239 RS ISO 3657  
xii.  Free fatty Acid as oleic acid, %  max 0.3 RS ISO 1740  
xiii.  Refractive Index at 40 °C  1.4530 -1.4590  RS ISO 6320  
4.5 Microbiology requirements  
Butter shall comply with the microbiological r equirements specified in Table 2.  
Table 2 ▬ Microbiological  requirements for Butter   
S/N  Microorganism  Maximum Limit  Test method  
I.  Total Viable Count, CFU/g  103 RS ISO 4833 -1 
II.  E. Coli , CFU/g  absent  RS ISO 11866 -2 
III.  Salmonella spp, CFU in 25g  absent  RS ISO 6579 -1 
IV.  Moulds , CFU/g  10  RS ISO 6611  
V.  Yeasts , CFU/g  10  
 
5 Food additive s 
Food additives which may be used  shall comply with RS CODEX STAN 192.  
6 Contaminants  
6.1 Heavy metals  
Butter shall not contain heavy metals in excess of those given in Table  3. 
Table 3 ▬Maximum limits  for heavy metals  
S/N  
 Heavy metals  Maximum level (mg/kg ) Test method  
I.  Lead as Pb  0.02 AOAC 999.11  
II.  Zinc as Zn  0.05 ISO 11813  
III.  Iron as Fe  2 RS ISO 6732  
IV.  Copper as Cu  0.05 RS ISO 5738  
6.2 Pesticide and veterinary drug residues  
The products covered by this standard shall comply with the maximum residue limits for veterinary drug and 
pesticide residues established in Codex Standard Guide for Maximum Pesticide Limits in Foods.  DRS 51: 2017  
5                ©RSB 2017 - All rights reserved  
 6.3 Aflatoxins  
When tested in accordance with ISO 14501, the level of Aflatoxin M1shall not exceed 0.50  μg/kg 
7 Hygiene  
The product s covered by the provision of this standard shall be prepared and handled in accordance with RS 
CAC/RCP 1 . 
8 Packaging  
Butter shall be packaged in food grade containers which shall safeguard the quality of the product . 
9 Labelling  
In addition to the requirements specified in RS EAS 38, the following requirements shall apply:  
a) name or the product as “Butter”  
b) Words denoting the animal or, in the case of a mixture, all the animals from which the milk has been derived, 
should be inserted  immediately before the designation of the product.  
c) Butter may be labelled to indicate whether it is salted or unsalted.  
d) name, address and physical location of the manufacturer/ packer;  
e) list of ingredients;  
f) declaration of Milk Fat Content;  
g) lot number;  
h) date of manufacture;  
i) expiry date;  
j) Country of origin  
k) Net contents  in mass  
l) Storage conditions   
©RSB 2017 - All rights reserved                  2 
 10 Sampling  
Sampling shall be done in accordance with the methods prescribed in RS ISO 707 . 
 DRS 51:2017  
ICS 67.100.20  
 
©RSB 2017  - All right s reserved