KENYA STANDARD                      DKS2859 : 2018  
                                                                                                       ICS  
  
 
 
 
 
 
  
 
 
 
 
 
 
 
 
 
 Sweetpotato Bread  - specification  
 
 
 
 
 
 
                         
 
 
 
 
 
 
 
 
 
    © KEBS 2018  First Edition  
 
 
 
  KENYA STANDARD                                            DKS2859: 2018  
                                                                                                                              ICS  
KEBS 2018  — All rights reserved    ii  
TECHNICAL COMMITTEE REPRESENTATION  
 
The following organizations were represented on the Technical Committee:  
 
University of Na irobi 
Agriculture and Food Authority - Food C rops directorate  
Kenya Agricultural & Livestock Research Organization  
International Potato Center  
Kenya Industrial Research & Development Institute  
Food science and Technology platform of Kenya  
National Potato Council of Kenya  
Propack Ltd.  
Graduate Africa Ltd  
Kenya Bureau of Standards — Secretariat  
 
 
 
 
 
 
 
REVISION OF KENYA STANDARDS  
 
In order to keep abreast of progress in industry, Kenya Standards shall be regularly reviewed.  Suggestions 
for improvements to publ ished standards, addressed to the Managing Director, Kenya Bureau of Standards, 
are welcome.  
 
 
 
 
 
 
 
© Kenya Bureau of Standards, 2018  
 
Copyright. Users are reminded that by virtue of Section 25 of the Copyright Act, Cap. 130 of 2001  of the Laws of Kenya, copyright 
subsists in all Kenya Standards and except as provided under Section 25 of this Act, no Kenya Standard produced by Kenya Bure au of 
Standards may be reproduced, stored in a retrieval system in any form or transmitted by any means without prior per mission in writing 
from the Managing Director . 
 
 
 
 
 
  
 KENYA STANDARD                                            DKS2859: 2018  
                                                                                                                              ICS  
KEBS 2018  — All rights reserved    iii  
 
 
 
 
 
 
 
 
 
 
 
 
 Sweetpotato Bread  - specification  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
KENYA BUREAU OF STANDARDS (KEBS)  
 
Head Office: P.O. Box 54974, Nairobi -00200, Tel.: (+254 020) 605490, 602350, Fax: (+254 020)  60403 1 
E-Mail: info@kebs.org, Web:http://www.kebs.org  
 
Coast Region     Lake Region    Rift Valley Region  
P.O. Box 99376, Mombasa -80100   P.O. Box 2949, Kisumu -40100        P.O. Box 2138, Nakuru -20100  
Tel.: (+254  041) 229563, 230939/40  Tel.: (+254 057) 23549, 2239 6       Tel.: (+254 051) 210553, 210555  
Fax: (+254  041) 229448    Fax: (+254 057) 21814  
 KENYA STANDARD                                            DKS2859: 2018  
                                                                                                                              ICS  
KEBS 2018  — All rights reserved    iv  
 
Foreword  
 
This Kenya Standard has been developed by the Tubers and Tuber  Products Technical Committee under 
the guidance of the Standards Projects Committee and it is in accordance with the procedures of the Kenya 
Bureau of Standards.  
 
The development of this standard is in response to the need to accommodate the emerging quality, 
innovation , technological and environmental issues in the sector. The implementation of  the s tandard is 
aimed at creating harmony , quality , uniformity and fair trade in the sector, thereby creating value for the 
stakeholders.  
 
In the development of this standard it was envisaged that the current paradigm of sustainable development 
shall be ensured in the context of social, economic and environmental concerns. The standard  thus intends 
to safeguard the interests of the stakeholders in the entire value chain, guarantee product quality and 
enhanced safety of the consumers.  
 
In the development o f this standard, reference was made to the following documents:  
Recommended International Code of Practice General Principles of Food Hygiene.  
EAS 43 - Bread - specification  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
 
 
 DKS2859: 2018    
 
 
KEBS 2018  — All rights reserved   
 5 Sweetpotato bread -Specification 
 
 
 
1        Scope  
 
This S tandard specifies requirements and methods of sampling and test for Sweetpotato bread  
obtaine d from the processing of sweetpotato  (ipomea batatas ) intended for hum an consumption. 
 
2        Normative references  
 
The following referenced documents are ind ispensable for the application of this documen t. For dated 
references, only the edition cited applies. For unda ted references, the latest edition of the referenced 
document  (including any  amend ments) appli es. Adopt as the puree  
 
 KS EAS 12, Potable water – Specif ication  
 
 KS EAS 35, Edible salt – Specification  
 
 KS EAS 38, General standard for the labelling of pre -packaged foods  
 
  KS EAS 39, Hygiene in the food and drink manufacturing industry – Code of practice  
 
 KS EAS 321, Edible fats and oils  
 
  KS EAS 773 , Sweet potato flour — Specification 
 
KS EAS 803,  Nutrition labelling -Requirements  
 
KS EAS 804 , Claims — General requirements  
 
KS EAS 805, Use of nutrition and health claims 
Requirements  
 
 DKS 2860  Sweet potato puree - specification  
 
  KS EAS 771 , Fresh swee t potato — Specification 
 
   KS C ODEX Stan 192,  General standard for food addi tives 
 
   KS C ODEX STAN 193,  Codex gene ral standard f or contaminants and  toxins in food and feed 
 
   KS ISO 1842,  Fruit and vegetable p roducts — Determination of  pH 
 
KS I SO 6579,  Microbiology of food and animal feeding  stuffs — Horizontal method for the 
detection of Salmonella spp. 
 
ISO 7251, Microbiology of food and animal feeding stuffs — Horizontal method for the detection and 
enumeration of presumptive Escherichia coli — Most probable number technique  
 
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 0.9  
 
ISO 24333, Cereals and cereal products — Sampling  
 
 
 DKS2859: 2018    
 
 
KEBS 2018  — All rights reserved   
 6  
3. Definitions  
 
For the purpose of this standard the following definitions apply.  
 
3.1 
Sweetpotato bread  
 
product obtained by baking fermented dough made from  at least 20 % of sweetpotato puree   or 10%  
sweetpotato f lour  
 
4.  Essential  quali ty and compositional  requirements  
 
4.1   Raw mater ials 
 
The follow ing materials shall be u sed in  the pr ocessing of sweetpotato  bread: 
 
4.1.1 flour conforming to relevant Kenyan/ East African Standards;  
  
4.1.2 sweet potato flour/ puree conforming  to the relevant Kenyan/ East 
African Standards  
 
 4.1.3  baker’s yeast conforming to relevant East African Standard;  
 
  4.1.4  edible oils and fats conforming EAS 321;  
  
   4.2.4 potable water complying with EAS 12  
 
4.2      Optional  ingredie nts 
 
   4.2.1 Food additives conforming to CODEX  STAN 192  
   4.2.2  edible  common salt EAS 35;  
   4.2.3 sugar  conforming to EAS 5;  
   4.2.4 milk or milk products;  
 
   4.2.5 gluten ; 
 
    4.2.6 oilseeds and oilseed products;  
 
   4.2.7 fruits  and fruit produ cts; and  
  4.2.8 any  food products  fit 
for human consumption.  
 
 
4.3 General Quality requirements  
 
4.3.1 Bread crust  
The crust shall have a golden brown colour and shall be free from blisters. The crust shall be not  
burned and shall be free from soot or any  other foreign matter. The bread shall be evenly baked on all  
sides including the bottom. The crust shall not be thin and break easily. It shall not be thick, tough, or  
rubbery.  
 
4.3.2 Volume  
The bread shall have volume to weight ratio of not more than 5.7 5 to 1 when tested according to Annex B  DKS2859: 2018    
 
 
KEBS 2018  — All rights reserved   
 7  
4.3.3 The crumb  
The crumb shall be springy, with small pores uniformly distributed throughout and with thin cell walls.  
It shall be free from non -porous mass, lumps of flour or salt, or any other evidence of incompl ete 
mixing.  
There shall be no hollow between the crust and the crumb.  
The crumb shall have colour characteristic of the ingredients used. When sliced, the surface of slices  
shall present a uniform shade without streaks or dark patches.  
 
4.3.4 Flavour  
The f lavour shall be characteristic of fresh, well -baked bread, free from abnormal flavour or any other  
objectionable flavour.  
 
4.3.5 Aroma  
The aroma shall be fresh and shall not be musty, metallic or sour.  
 
4.3.6 Mould or Rope  
The bread shall be free from indi cations of rope or mould.  
 
4.3.7 Internal texture  
The structure shall be uniform with thin -walled cells. The texture is soft and velvety, without  
weakness, and shall not crumble.  
 
4.3.8 Taste mastication  
The bread shall have a pleasant and acceptable taste . The loaf shall be free from doughiness and not  
dry or tough.  
 
4.3.9 Foreign matter  
The bread shall be free from any foreign matter except for a small amount of added edible grains  
dusting bran, maize flour or rice flour from the baker's shovel which may adhere to the bottom of the  
loaf. 
 
4.3.10   the premises, equipm ent and facilities for production of sweetpotato bread shall be 
located, designed and constructed to ensure that:  
a) contamination is minim ized; 
 
b) it will permit  appropriate main tenance, cleani ng and sanitizing; and 
 
c) there is e ffective pro tection against pest access and harbourage. 
   
4.3.11 s w e e t p o t a t o  b r e a d  s h a l l  b e  p r e p a r e d  a n d  h a n d l e d  i n  
a c c o r d a n c e  w i t h  t h e  requirements of EAS39  
 
 
4.4     Specific  compositional  requirements  
 
Sweetpotato  bread shall conform to the requirements specified in T able 1.  
 
 
 
 
 
 
 DKS2859: 2018    
 
 
KEBS 2018  — All rights reserved   
 8 Table 1 —  compositional Requirements for sweetpotato  bread  
 
S/N Para meter Requirements Meth od of t est 
1 Moisture content, %, by mass, max. 40 ISO 712  
4 Acid insoluble ash, %, by mass, max 0.20 Annex  A-  
5 pH of aqueous extract 5.3 – 6.0 ISO 1842  
 
 
 
 
5    Hygiene  
 
5.1       Sweetpotato  bread shall be prepared and handled in a hygienic manner in accordance with 
EAS 39 and shall conform to microbiological limits specified in Table 2.  
 
5.2       During handling, storage and transportation, effective measures must be taken to prevent cross 
contamination with chemicals, mic robial or physical contaminants  
 
 
Table 2 — Microbiological limits for sweetpotato  bread  
 
S/N Micro -organism(s)  Requirements  Method of test  
1 Escherichia coli, cfu/g.  Absent    ISO 7251  
2 Salmonella , 25g.  absent  ISO 6579  
3 Yeasts and moulds, cfu/g, max.  103 ISO 21527 -2 
 
 
6      Contaminants  
 
6.1      Pesticide  residues  
 
Sweetpotato  bread shall conform to maximum  residue limits for pesticide residues established by 
the Co dex Alimen tarius Commission for this commodi ty. 
 
6.2     Other  contaminants  
 
Sweetpotato  bread  shall comply with the maximum levels of the Codex General Standard for 
Contaminants and Toxins in Food and Feed (COD EX STAN 193).  
 
7     Packaging  
 
 Sweet potato b read shall be packaged in food grade materials that will safeguard the hygienic, nutritional 
and organoleptic qualities of the product.  The packaging material used shall comply  with the national 
regulations.  
 
 
8     Weights and measures  
 
 Sweet potato b read shall be package d in accordance with the weights and measures requirements in 
the destination country.   
 DKS2859: 2018    
 
 
KEBS 2018  — All rights reserved   
 9 9     Labelling  
 
9.1 In addition to the requirements of EAS 38 , the following specific labelling  requirements shall apply   
        and shall be legibly and indelibly marked:  
 
a)    common na me of the pro duct ‘Sweetpotato  Bread’;  
 
b)   name,  and physical address of the man ufacturer/ distributor and /or trade    name/ brand 
name ;    
 
c)      date of manu facture; 
 
d)      list of ingred ients; 
 
e)      lot identification; 
 
f)       expiry date; 
 
g)      the net  weight in me tric un its; 
 
h)      storage instructions; 
 
i)      declaration of additives used   
 
j)    instructions on disposal of used package. 
 
 
9.2   When labelling non-retail packages, information for non-retail packages shall ei ther be given on 
the packages or in accompanying documents, except that the name of the product, lot id entification 
and the na me and ad dress of the manu facturer or packer shall ap pear on the packages. 
 
9.3 Nutrition labelling  
The amount of nutrients in the sweetpotato bread  shall be declared on the label in accordance  with KS 
EAS 803 . 
9.4 Nutrition and health claims  
sweetpotato bread  may have claims on the importance of the micronutrients in nutrition and heal th. Such 
claims when declared shall be in compliance with KS EAS 804 and KS EAS 805.  
 
 
10      Sampling  
 
 Sampling shall be done in accordance with ISO 24333.  
 
11     Criteria  for conformi ty 
A lot shall be de clared as conforming to this standard if samples inspected or analyzed for quali ty 
requirements conform to the pro visions of this standard.DKS2859 : 2018  KENYAN STANDARD  
 
 1 B
1
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Annex A  
(normative)  
Determination of acid insoluble ash  
 
A.1 Reagents  
Dilute hydrochloric acid, prepared by diluting concentrated hydrochloric acid with water in a ratio of 
2:5. 
 
A.2 Apparatus  
A.2.1 Muffle furnace at 600°C ± 20°C  
A.2.2 Water bath  
 
A.3 Procedure  
Weigh accurately 5 g -10 g of finely powdered bread in a porcelain or platinum dish. Ignite the material 
in the dish with a suitable flame until it chars. P lace the ignited bread in the muffle furnace.  
  Heat at 600°C C ± 20°C for at least 1 h. Remove the dish from the furnace and cool.  
 
Wet the ash with a suitable amount of hydrochloric acid, and place on a water bath for 10 min. Filter 
through a No. 1 sinte r glass crucible. Wash the crucible with water until the washings are free from 
acid. Dry the crucible in an air -oven for 2 h. Cool in a desiccator and weigh. Repeat the process until 
the difference between two successive weighings is less than 1 mg. Take the lowest mass.  
 
A.4 Calculation  
Acid insoluble ash, percent by mass (on dry basis) = M2   X 100 /M1 
 where,  
 
M1 is the mass of sample, and  
 
M2 is the of insoluble matter.DKS2859 : 2018  KENYAN STANDARD  
 
 
 
 
 
 Annex B  
(normative)  
Determination of volume/weight ratio  
 
B1. Apparatus  
B1.1 Rigid c ontainer  
B1.2 Rape seeds  
B1.3 Weighing scale  
B1.4 Measuring cylinder  
B1.5 Loaf volumeter  
B1.6 Plate  
B2 Determination of volume/weight ratio by displacement method  
B2.1 Procedure  
Weigh the loaf after it is cooled to room temperature and record the weight. F ill the container with  
rape seeds and level the top of seeds with a plate. Empty out the seeds leaving a layer at the bottom  
of the container. Place the loaf on the layer of seeds. Fill the rest of the container with seeds and level  
the top surface with a plate. Pour the remaining rape seeds into the measuring cylinder and measure  
the volume.  
B2.1.1     Volume   (V)   /weight ratio for the bread  ( W)  = ---------  
where,  
V is the volume in ml of the remaining seeds after displacement;  
W is the weight in g of t he loaf.  
NOTES  
1. Do not press the loaf while keeping in the box.  
2. For sliced bread, test before bread is sliced.  
 
 
B3 Determination of volume of loaf by loaf volumeter  
B3.1 Procedure  DKS2859 : 2018  KENYAN STANDARD  
 
 
 
 
 
 B3.1.1 Calibration of volumeter with dummy loaf  
Open the container and  place a dummy loaf into it. Close the container and open the gate.  
Remove the hopper lid and fill the calibrated column with rape seeds. Tap the column three  
times to ensure maximum use of seeds around the dummy loaf. Empty all excess seeds by  
closing the  gate and swinging down the column. Return the column to upright position and  
secure the lid to the container. Open the gate and swing down the volumeter to allow rape  
seeds to empty from bottom pan. When it is completely empty, close the gate and swing th e 
volumeter to upright position.  
B3.1.2 Measurement of the volume of loaf  
Weigh the loaf after it is cooled to room temperature and record the weight. Place the loaf in the 
volumeter  
and repeat the procedure as that for dummy loaf. The volume of the loaf w ill be indicated by the level  
of seeds in the calibrated column.  
NOTE: The loaf must be larger than the dummy loaf.  
B3.1.3 Volume  ( V)  /weight ratio for the bread  ( W) = --------  
where,  
V is the volume in ml of the loaf;  
W is the weight in g of the loaf.