Cereals — Whole and dehulled sorghum grains for 
human consumption — Specification  BOTSWANA  STANDARD  BOS  26:2022  
Edition 3.0 BOS  26:2022  
 
BOTSWANA BUREAU OF STANDARDS   
 
 
  
 
 
 
 
 
 
 
 
 
 
 
 
 
  
 
 
 
 
 Copyright Protection Notice  
 
© BOBS [ 2022] – All rights reserved  
This Botswana standard is copyright -protected by BOBS. Unless otherwise specified, no part of this publication 
may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including 
photocopying, or posting on the Internet or an Intranet, without prior written permission. Requests for 
permission to reproduce should be addressed to BOBS at the address below.  
Botswana Bureau of Standards  
Privat e Bag BO 48  
Gaborone, Botswana  
Telephone:  +267 3903200  
Fax: +267 3903120  
E-mail:  infoc@hq.bobstandards.bw  
Website:  www.bobstandards.bw  
 
ICS 67.060  
Published in Botswana  
 
 
 BOS  26:2022  
Edition 3.0 
  
© BOBS [2023] –  All rights reserved 
i Contents  Page  
Foreword  .................................................................................................................................................. 1 
1 Scope  ........................................................................................................................................... 1 
2 Normative References  ................................................................................................................ 1 
3 Definitions  ................................................................................................................................... 2 
4 Requirements  .............................................................................................................................. 2 
4.1 Quality factors -  General  ............................................................................................................ 2 
4.2 Quality factors –  Specific  ........................................................................................................... 2 
4.2.1  Colour  .......................................................................................................................................... 2 
4.2.2  Moisture content ......................................................................................................................... 2 
4.2.3  Protein content ........................................................................................................................... 3 
4.2.4  Test weight .................................................................................................................................. 3 
4.2.5  Tannin Content ........................................................................................................................... 3 
4.2.6  Mycotoxins  .................................................................................................................................. 3 
4.2.7  Heavy metals  ............................................................................................................................... 3 
4.2.8  Pesticide Residues  ..................................................................................................................... 3 
4.2.9  Hygiene  ........................................................................................................................................ 3 
4.3 Grading and classification  ......................................................................................................... 4 
4.3.1  Food  class sorghum  (FOC) ........................................................................................................ 4 
4.3.2  Characteristics of class FOC  ..................................................................................................... 4 
4.3.3  Class FOC  .................................................................................................................................... 5 
5 Test methods  .............................................................................................................................. 5 
6 Sampling  ...................................................................................................................................... 5 
7 Labelling and packaging  ............................................................................................................ 5 
Bibliography  .............................................................................................................................................  6 
 
 
  
 
 BOS  26:2022  
Edition 3.0 
  
 
ii Foreword  
This Botswana Standard  was approved by the Technical  Advisory  Committee of the Standard  Council  on    
2022- 08-09. 
 
The Botswana  Bureau of Standards  (BOBS)  was established  under  the Standard  Act No. 16 of 1995  with a 
primary  responsibility  of preparing Botswana Standards.  
 During  the preparation of this standard,  assistance  was derived from ARS 462:2016, Sorghum  — Specification  
and Codex  Alimentarius  CXS 172-1989,  Standard for Sorghum grains.  
 This Botswana Standard is a revision  of, cancels  and replaces  BOS 26:2009.  
 
During  the preparation  of this standard the following  organizations  were  directly  represented  in the Cereals  and 
Pulses  Technical  Committee:  
 
Botswana  University  of Agriculture  Mr G Legwaila  (Chairperson)  
and Natural  Resources  – Department  of Crop  
and Soil Sciences     
Botswana Bureau of Standards  Mr O J Moje  (Technical  Secretary)  
Bokomo  Mr J Venter  
Bolux  Group  Ms G Ntope  
Botswana University  of Agriculture  
and Natural  Resources  – Department  of Crop 
and Soil Sciences  Dr. G Malambane  
Botswana University  of Agriculture  
and Natural  Resources  – Department  of 
Food Science and Technology  Prof.  G Bultosa  
Jagwa Investments  Mr J O Jagwer  
Honey  Guide  Ms T M Phiri 
Ministry of Agriculture,  
Department  of Crop Production  Mr M Khukhutha  
National  Food  Technology Research  Centre  Mr S Mpotokwane  
 
 
 
 
 
 
 
 
  
 
 
© BOBS [ 2022] – All rights reserved   
BOS  26:2022  
Edition 3.0 
 
 
© BOBS [2022] – All rights reserved 
1 Cereals — Whole and dehulled sorghum grains for 
human consumption  — Specification  
1 Scope  
This Botswana Standard applies to whole and dehulled/decorticated sorghum grains obtained from Sorghum 
bicolor (L). Moench.  
2 Normative References 
The following normative documents contain provisions which, through reference in this text, constitute provisio ns of this Standard. For dated references, subsequent amendments to, or revisions of, any of these 
publications do  not apply.  However,  parties  to agreements  based  on this Standard  are encouraged  to 
investigate  the possibility  of applying the most recent editions of the normative documents indicated below. 
For undated references, the latest  edition of the normative document  referred  to applies.  BOBS maintain  
registers  of currently  valid Standards.  
 
AOAC  Official Method 2001.04,  Determination of Fumonisins B 1 and B2 in corn and corn flakes  — Liquid 
chromatography with immunoaffinity  column clean up. 
BOS 63, Classification  and grading and classification  of sorghum grains  for sale in Botswana – Specification.  
BOS CAC/RCP1  – 1969,  Recommended International  code of practice – General  principles  of food hygiene.  
BOS ISO 13690, Cereals, pulses  and milled products – Sampling of static batches Codex Alimentarius, 
Volume 1, Cereals,  pulses, legumes,  and derived products and vegetable  proteins.  
Codex  Alimentarius,  Pesticides  residues  in food ‒ Maximum  residue  limits;  extraneous  maximum residue limits.  
ISO 605:1991 Pulses  — Determination of impurities,  size, foreign odours,  insects,  and species  and variety  — 
Test methods  
ISO 712: 1998,  Cereals  and cereal  products  ‒ Determination of moisture content  ‒ Routine reference method.  
ISO 5223:1995 Test sieves  for cereals.  
ISO 5983:  1997,  Animal feeding stuffs  ‒ Determination  of nitrogen content  and calculation of crude  protein  
content -Kjeldahl  method.  
ISO 6561- 1, Fruits, vegetables and derived products — Determination of cadmium content — Part 1: 
Method using graphite furnace atomic  absorption spectrometry  
ISO 6561- 2, Fruits, vegetables and derived products — Determination of cadmium content — Part 2: 
Method using flame atomic  absorption spectrometry  
ISO 6633, Fruits, vegetables and derived products — Determination of lead content — Flameless 
atomic  absorption spectrometric  method  
ISO 9648:1988,  Sorghum ‒ Determination of tannin content.  
ISO 16050:2003 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  
  
BOS  26:2022  
Edition 3.0 
 
 
© BOBS [2022] – All rights reserved 
2 3 Definitions  
For the purpose of  this Botswana Standard the following definitions shall apply  
3.1 Sorghum  grains: whole grains obtained from species of Sorghum bicolor (L) Moench, after a complete 
threshing without any further treatment.  
 
 3.2 Dehulled /decorticated sorghum  grain: grains  of sorghum from which all or  part of the bran and    germ 
have been removed.  
 3.3 defective grain: pieces of grain or grains of sorghum which :  
 a) is broken, rotten, mouldy, smutty, or otherwise diseased;  
b) the embryo skin is cracked;  
c) grain is immature;  
d) has been damaged by insects, heat, or any other means, but does not include weather stained sorghum; and, 
e) passes through a 1.8 mm slotted sieve.  
  3.4 weather -stained  grains: means sorghum grains of which more than one- third of the surface of the  
pericarp is distinctly discoloured by the weather, but does not include sorghum kernels with purple anthocyanic blotches in or on the pericarp.  
 
 3.5 foreign  matter: all organic or inorganic materials other than sorghum grains such as sticks, stones, clods, 
dung, chaff, other portions of the sorghum plant, other plants and seeds of other plants.  
  3.6 technological  qualities: refers to physico- chemical properties of the product.  
4 Requirements  
4.1 Quality factors -  General  
The product  shall meet  the following  quality  factors:  
 
a) safe and suitable  for human  consumption;  
 
b) free from abnormal  flavours  and odours/aroma;  
 
c) shall not have filth (impurities of animal origin, including insects) and impurities of plants in amounts which may constitute a hazard to human  health; and,  
 
d) shall not have  noxious  and toxic seeds,  or their components  including but  not limited to  crotolaria  
(Crotolaria spp.),corn cockle ( Agrostemma githago L., castor bean ( Ricinus communis L.) and jimson 
weed  (Datura spp.).  in amounts  that may constitute  a hazard tohuman health.  
 
4.2 Quality factors –  Specific  
4.2.1  Colour  
Sorghum  grains  may be white,  pink,  red, brown,  orange,  or yellow  in colour,  or a mixture  of these colours.  
 
4.2.2  Moisture content 
The moisture content of lots of sorghum grains shall not exceed 13 % by mass as determined according to 
ISO 712.  
BOS  26:2022  
Edition 3.0 
 
 
© BOBS [2022] – All rights reserved 
3 4.2.3  Protein content 
The protein content  (N x 6.25)  shall not be less than 7 % on a dry matter  basis  as determined according 
to            ISO 5983.  
 
4.2.4  Test weight 
When tested in accordance with ISO 605, density of grade 1 sorghum grains shall not exceed 71 kg/hl of 
which grade 2 sorghum grains shall not exceed 62kg/hl.  
 
4.2.5  Tannin Content 
The tannin content  shall not exceed 0.5 % for whole sorghum grains,  0.3 % on dehulled/decorticated  
grains  on a dry matter basis,  as determined according  to ISO 9648.  
 
4.2.6  Mycotoxins  
Sorghum grain shall comply with the mycotoxin limits established by the Codex Alimentarius Commission 
as given in Table 2 when tested in accordance with the test methods specified therein.  
 
Table 2 — Mycotoxins limits for Sorghum grains  
Mycotoxin  limit Test method  
Total  Aflatoxin  
(AFB1+AFB2+AFG1+AFG2),  
ppb, max 10 ISO 16050  
Aflatoxin  B1 ppb, max 5 
Fumonisins  ppm,  max 2 AOAC Official Method  
2001.04  
 
4.2.7  Heavy metals  
Sorghum grains shall comply with those maximum limits for heavy metal contaminants specified in CXS  193 
and in particular those listed in Table 1 . 
Table 1 —Heavy metal contaminants  
Parameter  Limit  (ppm  max)  Test method  
Lead  (Pb) 0.1 ISO 6633  
Cadmium  (Cd) 0.02 ISO 6561 -1 or ISO 6561 -2 
 
4.2.8  Pesticide Residues  
Sorghum grains  shall comply  with those maximum residue limits  established by the Codex  Alimentarius  
Committee on Pesticide Residues for this commodity as spelt out in Pesticide Residues in food –  Maximum  
Residue limits.  
 
4.2.9  Hygiene  
The product covered by the provision of this standard shall be handled, prepared, packed, transported and  
distributed under hygienic conditions. When tested by appropri ate methods of sampling and examination, 
the product  shall be free from microorganisms  and substances  originating from microorganisms  or other  
poisonous  or deleterious substances  in amounts,  which  may constitute a  hazard to human health.  
  
BOS  26:2022  
Edition 3.0 
 
 
© BOBS [2022] – All rights reserved 
4 It is also recommended that the products covered by the provisions of this standard be prepared and 
handled in accordance  with the appropriate sections of  the BOS CAC/RCP  1. 
 
4.3 Grading and classification  
4.3.1  Food  class sorghum  (FOC) 
Food class  sorghum  shall comprise  three sub-classes:  
 
a) Food class  sorghum - White  (FOCW);  
 
b) Food class sorghum - Red (FOCR);  
 
c) Food class  sorghum  - Other  colour  (FOCO);  
 
4.3.2  Characteristics of class FOC  
A consignment  of sorghum shall be classified  as class FOC  sorghum if it has the following  characteristics:  
 
a) consists of sorghum  that does  not have  a dark testa;  
 
b) the grains  are of intermediate to hard endosperm texture;  
 
c) consists of either  white  grains  (sub- class FOCW);  red grains  (sub- class FOCR);  or is of grain  
colour  other  than white  or red, or a mixture  of grain colours  (sub- class FOCO);  
 
d) is of a FOC  cultivar,  as specified  by the Department  of Agricultural Research of the Ministry  of 
Agriculture;  
 
e) complies  with the requirements  for one of the grades  of class FOC  sorghum as set out in Table  1. 
 
Table  1 — Permissible purity characteristics in sorghum  
 Maximum  extent  to which  defects  are permissible  in % 
 
Nature  of deviation  Grade  FOC   
Methods  of analysis  
GR 1 GR 2 
Foreign  matter  * 1.5 2.0 Visual  examination  
Unthreshed  sorghum  4.0 6.0 Visual  examination  
Defective  sorghum  ** 3.0 6.0 BOS  63 -Annex  G 
Small  kernel  4.0 8.0 ISO 5223  
Sorghum  of other  classes  2.0 4.0 Visual  examination  
Sorghum  of another  colour  2.0 4.0 BOS  63 -Annex  D 
Total  of the above  defects  8.0 10.0 BOS  63 -Annex  G 
Weather  stained  sorghum  25.0 50.0 Visual  examination  
* of which  inorganic  matter  should  not exceed  0.5 %, and filth should  not exceed  0.1 %. 
** of which  rotten, smutty, or diseased grain  should not exceed  0.5 %.  
BOS  26:2022  
Edition 3.0 
 
 
© BOBS [2022] – All rights reserved 
5 4.3.3  Class FOC  
This class consists of the following  subclasses  and grades:  
 
a) Sub-class FOCW;  
 
(1) Grade FOCW  1; 
 
(2) Grade FOCW  2; 
 
b) Sub-class FOCR;  
 
(1) Grade FOCR 1; 
 
(2) Grade FOCR 2; 
 
c) Sub-class FOCO;  
 
(1) Grade FOCO  1; 
 
(2) Grade FOCO  2. 
5 Test methods  
 Testing shall be done in accordance  with the methods  referred to in this standard.  
6 Sampling  
 Sampling  shall be done in accordance with BOS  ISO 13690.  
7 Labelling and packaging 
In addition to the requirements  of the relevant  regulation1, the following requirements  shall be met: 
a) The specific  name of the  product to be  declared on the label shall be  either  ‘Whole sorghum 
grains’  or ‘Dehulled/  Decorticated sorghum grains’;  
 
b) Sorghum grains  shall be packaged in containers  which will safeguard the hygienic, nutritional,  
technological  and organoleptic  qualities of  the product;  
 
c) The containers, including packaging material, shall be made of substances, which are safe and 
suitable for  their intended use. They  shall not impart  any toxic substance or undesirable  
odour  or flavour  to the product; and,  
 
d) When  the product  is packaged in bags,  these  shall be clean,  sturdy  and strongly  sewn  or sealed.  
 
e) Net volume in accordance with relevant  regulations2 
 
Information  for non-retail  or bulk containers  shall either  be given  on the container  or in accompanying  
documents, except that the name of the product, lot identification and name and address of the 
processor or  packer shall appear on the container. However, lot identification, the name and address 
of the processor or  packer may be replaced by an identification mark, provided that such mark is clearly 
identifiable with the source  and accompanying documents.  
 
1 For Botswana:  Labelling  of pre-packaged foods  regulations  Cap 65:05  
2 For Botswana:  Weights  and Measures  Act, Chapter  43:0 
BOS  26:2022  
Edition 3.0 
 
 
© BOBS [2023] –  All rights reserved 
6 Bibliography  
 
1) For Botswana  Food Control  Act 1993,  Labelling of prepackaged foods  regulations  Cap 65:05 
 
2) For Botswana,  Weights  and Measures  Act, 2006,  Chapter  43:06.