Reference number  
DRS 149:2018  
© RSB 2018  
 
 
 RWANDA 
STANDARD  DRS 
149 
 
Second  edition  
2018-mm-dd 
 
Cooked beans  — Specification  
  DRS 149:2018  
©RSB 2018 - 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 2018 
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 149:2018  
iii                ©RSB 2018 - All rights reserved  
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ....................  v 
1 Scope  ................................ ................................ ................................ ................................ .............  1 
2 Normative references  ................................ ................................ ................................ ...................  1 
3 Terms and definitions  ................................ ................................ ................................ ..................  2 
4 Requ irements  ................................ ................................ ................................ ................................  3 
4.1 Raw materials  ................................ ................................ ................................ ...............................  3 
4.2 Optional ingredients  ................................ ................................ ................................ .....................  3 
4.3 General requirements  ................................ ................................ ................................ ..................  4 
4.4 Process requirements  ................................ ................................ ................................ ..................  4 
4.5 Specific requirements  ................................ ................................ ................................ ..................  4 
4.6 Defects and tolerances  ................................ ................................ ................................ ................  5 
4.7 Microbiological requirements  ................................ ................................ ................................ ..... 6 
6.1 Pesticide residues  ................................ ................................ ................................ ........................  6 
6.2 Other contaminants  ................................ ................................ ................................ ......................  6 
Annex  A (normative) Determination of drained weight  ................................ ................................ .........  8 
A.1 Definition  ................................ ................................ ................................ ................................ ....... 8 
A.2 Apparatus  ................................ ................................ ................................ ................................ ...... 8 
A sieve 20 cm (check) in diameter. The meshes of such sieves are made by so weaving wire as to 
form square openings of 2.8 mm by 2.8 mm.  ................................ ................................ ............  8 
A.3 Procedure  ................................ ................................ ................................ ................................ ...... 8 
A.4 Calculation  ................................ ................................ ................................ ................................ .... 8 
Annex  B (normative)  Determination of water capacity of containers  ................................ .................  9 
B.1 Scope  ................................ ................................ ................................ ................................ .............  9 
B.1.1  This method ap plies to metals and glass containers  ................................ ...............................  9 
B.2 Definitions  ................................ ................................ ................................ ................................ ..... 9 
B.3 Procedures  ................................ ................................ ................................ ................................ .... 9 
B.3.1  Metal co ntainers  ................................ ................................ ................................ ...........................  9 
B.3.2  Glass containers  ................................ ................................ ................................ ...........................  9 
B.4 Calculation  ................................ ................................ ................................ ................................ .... 9 
B.4.1  Metal containers  ................................ ................................ ................................ ...........................  9 
B.4.2  Glass containers  ................................ ................................ ................................ .........................  10 
Annex  A (informative)  Determination of drained weight  .........................  Error! Book mark not defined.  
A.1 Definition  ................................ ................................ ..........................  Error! Bookmark not defined.  
A.2 Apparatus  ................................ ................................ .........................  Error! Bookmark not defined.  
A sieve 20 cm (check) in diameter. The meshes of such sieves are made by so weaving wire as to 
form square openings of 2.8 mm by 2.8 mm.  ...............................  Error! Bookmark not defined.  
A.3 Procedure  ................................ ................................ .........................  Error! Bookmark not defined.  
A.4 Calculation  ................................ ................................ .......................  Error! Bookmark not defined.  
Annex  B (normative)  Determination of water capacity of containers  .... Error! Bookmark not defined.  
B.1 Scope  ................................ ................................ ................................  Error! Bookmark not defined.  
B.1.1  This method applies to metals and glass containers  ..................  Error! Bookmark not defined.  
B.2 Definitions  ................................ ................................ ........................  Error! Bookmark  not defined.  
B.3 Procedures  ................................ ................................ .......................  Error! Bookmark not defined.  
B.3.1  Metal containers  ................................ ................................ ..............  Error! Bookmark not defined.  
B.3.2  Glass containers  ................................ ................................ ..............  Error! Bookmark not defined.  
B.4 Calculation  ................................ ................................ .......................  Error! Bookmark not defined.  DRS 149:2018  
©RSB 2018 - All rights reserved                  iv 
 B.4.1  Metal containers ................................ ................................ ...............  Error! Bookmark not defined.  
B.4.2  Glass containers  ................................ ................................ ..............  Error! Bookmark not defined.  
Annex C (normative)  Determination of sodium chloride content  ................................ .....................  11 
C.1 Scope  ................................ ................................ ................................ ................................ ..........  11 
C.2 Definition  ................................ ................................ ................................ ................................ .... 11 
C.3 Principle  ................................ ................................ ................................ ................................ ...... 11 
C.4 Reagents  ................................ ................................ ................................ ................................ ..... 11 
C.5 Apparatus  ................................ ................................ ................................ ................................ ... 11 
C.6 Procedure  ................................ ................................ ................................ ................................ ... 12 
Annex D (normative)  Determination of soluble solids(Brix)  ................................ .............................  13 
D.1 Definition  ................................ ................................ ................................ ................................ .... 13 
D.5 Reference  ................................ ................................ ................................ ................................ .... 14 
 DRS 149:2018  
v                ©RSB 2018 - 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 wit h 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 ratified  by me mbers of RSB Board of Director s for publication and gazettment as 
Rwanda Standards.  
DRS149 was prepared by Technical Committee RBS/TC 0 03, Cereals, Pulses, Legumes derived Products . 
In the preparation of this standard , reference was made to the following standard : 
1) CODEX STAN. 16 -1981 , Recommended international Standard for Canned Green Beans and Canned 
Wax Beans.  
2) IS 9790: 1981, Specification for canned fresh beans  
3) MS 998:1986, Canned Beans - Specification  
4) MS 997:2009, Canned baked beans in tomato sauce – specification  
The assistance derived from the above source is hereby acknowledged with thanks.  
This second  edition cancels and replaces the first edition (RS 149:2012) which has been technically revised.  
Committee membe rship  
The following organizations were represented on the Technical Committee on Cereals, pulses, legumes and 
cereal products  (RSB/TC 003) in the preparation of this standard.  
ADMA International Ltd  
FARMFRESH Ltd  
Lamane Bakery  
Rwanda Agriculture Board  
SIMBA Supermarket  
SOSOMA Industries  
Rwanda  Standards Board  (RSB) – Secretariat  DRS 149:2018  
©RSB 2018 - All rights reserved                  ii 
   DRS 149:2018  
1                ©RSB 2018 - All rights reserved  
 Cooked beans  — Specification  
1 Scope  
This Draft Rwanda Stan dard specifies the requirements, sampling and test methods for cooked beans.  
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 t his document.  For dated references, only the edition  cited applies. For undated references, the 
latest edition of the referenced document (including any amendments) applies.  
CODEX STAN 171, Codex standard for certain p ulses  
CODEX STAN  193, Codex general St andard for Contaminants and Toxins in Food and Feed  
EAS 901, Cereals and pulses —Test methods  
ISO 16050 , Foodstuffs — Determination of aflatoxin B1, and the total content of aflatoxins B1, B2, G1 and G2 in 
cereals, nuts and derived products — High-performance liquid chromatographic method  
ISO 16649 -2, Microbiology of food and animal feeding stuffs -- Horizontal method for the enumeration of beta -
glucuronidase -positive Escherichia coli -- Part 2: Colony -count technique at 44 degrees C using 5 -bromo-4-
chloro -3-indolyl beta -D-glucuronide  
ISO 5498, Agricultural food products — Determination of crude fibre content — General method  
RS 288, Mixed beans  —Specification  
RS 295,  Dry beans —Specification  
RS 362 , Fish flour —Specification   
RS CAC/RCP 1, Code of practice – General principles of food hygiene . 
RS CODEX STAN 192, Codex general standard for food additives  
RS EAS 12,  Potable water –Specification  
RS EAS 35 , Fortified edible salt  —Specification  
RS EAS 38,  Labelling of Prepackaged foods  and prepared foods   
©RSB 2018 - All rights reserved                  2 
 RS ISO 21527 -2, Microbiology of food and animal feeding stuffs -- Horizontal method for the enumeration of 
yeasts and moulds -- Part 2: Colony count technique in products with water activity less than or equal to 0,95  
RS ISO 24333 , Cer eals and cereal products — Sampling  
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  
3 Terms and definitions  
3.1  
dry beans  
dry threshed fiel d and garden beans, whole, or broken, and split, seed obtained from different variety of 
Phaseolus spp  commonly used for edible purpose.  
3.2  
drained weight  
weight of the contents of the container after draining according to the procedure set out in annex A. 
3.3 
food grade material  
material that is free from substances that are hazardous to human health and may be permitted to come in 
contact with food.  
3.4 
loose skin  
skin or portions of a skin which have become separated wholly from the cotyledons;  
3.5 
broken  
cotyledon or portions of a cotyledon which have become separated; or a bean or portions of a bean with the  
skin or portions of the skin missing;  
3.6 
mashed  
bean that is crushed or flattened to the extent that the appearance is seriously affected;  DRS 149:2018  
3                ©RSB 2018 - All rights reserved  
 3.7 
blemished  
bean that is affected or damaged by any means to the extent that its appearance or eating quality is adversely 
affected;  
3.8 
extraneous vegetable material  
vegetable material common to the bean plant or other plants that is harmless upon eating and includes, but is 
not limited to, peas, lentils, cereal grains and corn.  
4 Requirements  
4.1 Raw materials  
The following materials used in the preparation of Cooked packaged beans shall conform to the relevant 
standards:  
a) Dry beans, mixed beans and iron bio -fortified beans conforming to RS 295, RS 288 and DRS 350 
respectively; and  
b) Potable water conformin g to RS EAS 12.  
4.2 Optional ingredients  
In addition, the following optional ingredients if used shall conform to the relevant standards:  
a)  Sweetening ingredients - sucrose, invert sugar, dextrose, glucose syrup;  
b) Tomato paste/puree RS EAS 66 -3; 
c) Aromatic plants,  spices or extracts thereof;  
d) Cheese;  
e) Cooking oil;  
f)  Fish flour conforming to RS 362;  
g)  Dried vegetables; and  
h)  Fortified edible salt conforming to RS EAS 35.   
©RSB 2018 - All rights reserved                  4 
 4.3 General  requirements  
Cooked packaged beans shall:  
a)  be practically free from extraneous matter;  
b)  be free of off flavours and odours;  
c)  be practically free from any insects ; 
d)  be safe and suitable for human consumption;  
e) have uniform texture;  
f) be practically free from hard beans, mushy be ans, and beans with tough skins;  
g) be well cooked, slightly soft or s lightly firm; and their skins shall be  tender ;and 
h) be homogeneous in color and shape  of food.  
4.4 Process requirements  
The filled containers or retortable pouches shall be exhausted, sealed and sufficiently processed by heat to a 
scheduled temperature and time to ensure commercial sterility.  
4.5 Specific requirements  
4.5.1  Cooked packaged beans shall comply with the requirements specified in Table 1 when tested in 
accordance with test methods specified therein.  
Table 1 — Specific r equirements for cooked beans  
S/N  Parameter  Requirements  Methods of test  
i.  Total soluble solid in sauce, Brix, min  12 Annex D  
ii.  Salt content (as sodium chloride), % w/w 
max 1.2 Annex C  
iii.  Drained weight, % of net weight min  65 Annex A  
iv.  pH 5-6  
4.5.2   For cooked iron bio fortified beans, the levels of iron shall not exceed the limits in Table 2.  
Table 2 —Iron content in cooked bio fortified  beans  
S/N  Parameter  Requirement(mg/kg)  Test method  
i.  Class 1  ≥90 AOAC 999.10  DRS 149:2018  
5                ©RSB 2018 - All rights reserved  
 ii.  Class 2  <90 ≥80 
iii.  Class 3  <80 ≥60 
4.6 Defects and tolerances  
Cooked beans shall be reasonably free from defects and within the limit set forth herein for common defects as 
defined in Table 3. A container or product shall be considered as defective’ when it fails to meet one or more of 
the applicable quality requirem ents in colour, flavour and texture.  
Table 3 — Classification of “defects”  
S/N  
  Defects  
 Maximum limits (based  
on weight of drained 
beans)  Test method  
1.  Blemished beans (beans which are 
slightly stained or spotted)  2 % w/w  EAS 901  
2.  Severely blemished beans  
(beans which are spotted, discoloured or 
otherwise  
blemished to an extent that the 
appearance or eating quality is seriously 
affected; these shall include worm  
eaten beans)  2 % w/w  
3.  Bean fragments  
(portions of beans: separated or individual  
cotyledons; mashed, partial or broken 
cotyledons;  
and loose skins)  10 % w/w  
4.  Extraneous plant material  
(any vine or leaf or pod material from the 
bean plant, or other plant material)  0.5 % w/w  
5.  Total of the foregoing defects  12 % w/w  
6.  Minimum fill of  container  The container shall be  
filled with beans and  
the product (including  
packing medium) shall  
occupy not less than  
90% of the water  
Capacity of the  
container. The water  
capacity of the  
container is the volume  
of water at room  
temperature which the  
sealed container will  
hold when completely  
filled (see annex B).  Annex B   
©RSB 2018 - All rights reserved                  6 
 A container that fails to  
meet the requirement  
for minimum fill (90 per  
cent container capacity)  
of 3.6 shall be  
considered as fail  
4.7 Microbiological requirements  
Cooked beans shall comply with the microbiological r equirements specified in Table 4. 
Table 4 — Microbiological limits for Cooked beans  
S/N  Micro -organism  Maximum limits  Test m ethod  
I.  E .coli, CFU/g  Absent  ISO 16649 -2 
II.  Salmonella, ssp, CFU/ 25g  Absent  RS ISO 6579 -1 
III.  Yeasts and moulds, CFU/g  102 RS ISO 21527 -2 
IV.  Clostridium botulinum, CFU/g  Absent  RS ISO 7937  
5 Food additives  
Food additives which may be used in the preparation of cooked packaged beans shall comply with RS CODEX 
STAN 192.  
6 Contaminants  
6.1 Pesticide residues  
Cooked packaged beans shall conform to maximum residue limits for pesticide residues established by the 
Codex Alimentarius Commission for this commodity.  
6.2 Other contaminants  
Cooked beans shall comply with the maximum levels of contaminants and Toxins in Food as stipulated in 
CODEX STAN 193.  
7 Hygiene  
Cooked beans shall be prepared and handled in a hygienic manner in accordance with RS CAC/RCP 1  
8 Packaging  
Cooked beans shall be packaged in food grade materials made of substances which are safe and suitable fo r 
their intended use and which will not impart any toxic substance or undesirable odour or flavour to the product.  DRS 149:2018  
7                ©RSB 2018 - All rights reserved  
 9 Weights and measures  
Cooked beans shall be packaged in accordance with the Weights and Measures requirements.  
10 Labelling  
10.1 In addition to t he requirements of RS EAS 38, the following requirements shall apply and shall be legibly 
and indelibly marked:  
i) Name of the product “Cooked beans”; “cooked mixed beans”, “cooked iron -biofortified beans”;  
j)  declaration of iron content, if iron bio fortified beans have been used;  
k)  name, and physical address of the manufacturer/ distributor and /or trade name/ brand name;  
l)  date of manufacture;  
m)  lot identification;  
n)  expiry date;  
o)  country of origin;  
p)  the net weight in metric units;  
q) the statement ‘Human Food’ shall appear on the package;  
r)  storage instructions; and  
s)  Instructions on disposal of used package.  
10.2 When labelling non -retail packages, information for non -retail packages shall either be given on the  
packages or in accompanying documents, except that the name of the product, lot identification and the name  
and address of the manufacturer or packer shall appear on the packages.  
11 Sampling  
Sampling of cooked beans shall be done in accordance with RS ISO 24333.   
©RSB 2018 - All rights reserved                  8 
 Annex  A 
(normative ) 
Determination  of drained weight  
A.1 Definition  
Drained weight expresses percentage of solid content as determined by the procedure described below  
A.2 Apparatus  
A sieve 20 cm (check) in diameter. The meshes of such sieves are made by so weaving wire as to  
form square openings of 2.8 mm by 2.8 mm.  
A.3 Procedure  
Carefully weigh the clean and dry sieve. Weigh the container plus the contents. Empty the contents of the 
container into the sieve taking care to distribute the maize evenly. Without shifting the product, incline the sieve 
at an angle of approxi mately 17 % to 20° to facilitate drainage. Drain the product for two minutes and then weigh 
the sieve plus the product. Weigh the dry empty container  
A.4 Calculation  
Drained weight, as per cent of net weight =  
=100(M1−m°)
M3−M2 
Where,  
M is the weight, in Grams,  of the sieve:  
M1 is the weight, in grams, of the sieve with the product:  
M2 is the weight, in grams, of the empty container;  
M3 is the weight, in grams, of the container with the contents  
 
 
 
  DRS 149:2018  
9                ©RSB 2018 - All rights reserved  
 Annex  B 
(normative ) 
 
Determination of  water capacity of containers  
B.1 Scope  
B.1.1  This method applies to metals and glass containers  
B.2 Definitions  
The water capacity of a container is the volume of water at room temperature which the sealed container will 
hold when completely filed.  
B.3 Procedures  
B.3.1  Metal containers  
B.3.1.1  Select a container whi ch is undamaged in all respects  
B.3.1.2  Wash, dry and weigh the empty container after cutting out the lid without removing or altering the 
height of the double seam.  
B.3.1.3  Fill the container with water at room temperature to 4.8 mm vertical distance below the top level of 
the container, and weigh the container thus filled.  
B.3.2  Glass containers  
B.3.2.1  Select a container which is undamaged in all aspects  
B.3.2.2  Fill the container with water at room temperature to the level of the top thereof, and weigh  the 
container thus fi lled 
B.4 Calculation  
B.4.1  Metal containers  
Subtract the weight found in B.3.1.2 from the weight found in B.3.1.3. The difference shall be considered to be 
the weight of water required to fill the container. Results are expressed as militres of water.   
©RSB 2018 - All rights reserved                  10 
 B.4.2  Glass containers  
Subtract the weight found in B.3.2.2 from the weight found in B.3.2.3. The difference shall be considered to be 
the weight of water required to fill the container. Results are expressed as millitres of water.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 DRS 149:2018  
11                ©RSB 2018 - All rights reserved  
 Annex C  
(normative)  
 
Determination of  sodium chloride content  
C.1 Scope  
This method determines the content of chlorides  
C.2 Definition  
The chloride content corresponds to the sum of all anions (halides)calculated as sodium chloride precipitable 
with silver ions in a nitric acid solution.  
C.3 Principle  
Quantitative precipitation of the halides extracted from the ash in a nitric acid solution with AgNO 3 in excess. 
Back titration of the surplus AgNO 3 with ammonium thiocyanate, using ferric alum (ferric ammonium sulphate) 
as the indicator.  
C.4 Reagents  
C.4.1  Distilled or demineralized water  
C.4.2  AgNO3 solution, 0.1 N (16.9888 g AgNO3)  
C.4.3  NH4SCN solution, 0.1 N (7.6113 g NH4SCN). In practice a slightly higher weight is taken and the 
solution is adjusted by dilution against a 0.1 N AgNO3 solution.  
C.4.4  Cold saturated NH4Fe (SO4) 2.12H2O solution (approximately 40 %). The ensuing brown colouring is 
eliminated by adding pure nitric acid drop wise.  
C.4.5  HNO3 (approximately 30 %)  
C.4.6  Diethyl ether of nitrobenzene  
C.5 Apparatus  
C.5.1  Measur ing flask, 100 ml  
C.5.2  Burette, 50 ml  
C.5.3  Erlenmeyer flask, 200 ml   
©RSB 2018 - All rights reserved                  12 
 C.5.4  Pipettes  
C.5.5  Funnel, filtering paper  
C.6 Procedure  
The ash (residue after carbonization and incineration of the potato crisp at a maximum temperature of 550 °C 
in a muffle furnac e) obtained from 1 g – 2 g dry matter is extracted by means of 80 ml – 90 ml hot distilledwater 
acidified with a few drops of nitric acid. The washings are filtered off into a 100 ml measuring flask; after cooling 
distilled water is added until the mark is  reached (stock solution). In proportion to the expected chloride content 
aliquot part of this solution, which should preferably contain 50mg – 100 mg NaCl, taken off, distilled water being 
added to obtain a quantity of approximately 100 mlSubsequently 5 m l ferric alum solution (see C.4.4), 20 ml 0.1 
N AgNO 3 solution (see C.4.2) and 5 ml – 10 mlether or 1 ml nitrobenzene are added; titration is carried out by 
means of an ammonium thiocyanate solution0.1 N (see C.4.3), until the red coloring remains after st irring.  
C.7 Expression of results  
Report in percentage by weight to one decimal place.  
Chloride content=5.56(𝑉2−𝑉3)∗𝑉∗100
𝑉1∗𝑃 
 
where,  
P is the test portion, in mg, incinerated;  
V is the ml of the stock solution derived from the ash;  
V1 is the volume, in  ml, stock solution used from titration;  
V2 is the volume, in ml, AgNO 3 added;  
V3 is the volume, in ml, NH 4SCN necessary for back titration.  
 
 
 
 
 
 DRS 149:2018  
13                ©RSB 2018 - All rights reserved  
 Annex D  
(normative)  
 
Determination of soluble solids(Brix)  
D.1 Definition  
Determination of Total Soluble Solids (Brix)  
D.2 Scope  
All range of products with aqueous solution  
D.3 Apparatus  
Sieve No. 8 (model: BS410) 2.36 mmin diameter  
Analytical balance, capable of weighing to the nearest 0.001 g.  
Tin opener  
Stainless steel tray  
Spoon  
D.4 Procedure  
D.4.1  Adjust  the temperature of the sample to room temperature  
D.4.2  Open the cover (day light plate) at the refracting prism of the refractometer.  
D.4.3  Stir the samples thoroughly and wet the surface of the prism.  
D.4.4  Cover the prism with the day light plate.  
D.4.5 Look through the eyepiece at the opposite end of the refracting prism directly under the light source.  
D.4.6  Focus the eyepiece by turning the adjustment knob until a clear reading and a boundary line is seen.  
D.4.7  Record the reading.  
D.4.8  Flush the pr ism surface with distilled water.   
©RSB 2018 - All rights reserved                  14 
 D.4.9  Dry the surface with soft tissue.  
D.5 Reference  
At ago Hand Refractometer N Types Series Instruction Manual  
 
 
 
 
 
 
 
 
 
 
 DRS 149:2018  
ICS 67.230  
 
 
©RSB 2018  - All right s reserved