KENYA STANDARD                                           DKS  2816 :2023 
     ICS 65.120  
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Feed grade yeast products — 
Specification  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
© KEBS 2023 First Edition , 2023 
 
 
  DKS  2816:20 23 
ii  © KEBS 20 23 — All rights reserved   
TECHNICAL COMMITTEE REPRES ENTATION  
 
The following organizations were represented on the Technical Committee:  
 
Ministry of Agriculture and Livestock  Development — State Department for Livestock Development  
Kenyatta University  
Kenya Agricultural Research Institute (KARI)  
Kenya Marine and Fisheries Research Institute (KMFRI)  
Unga Farm Care EA Ltd.  
Diamond V Ltd.  
Depa rtment of Veterinary Services  
Association of Kenya Feed Manufacturers — AKEFEMA  
Government Chemist Department  
Pioneer Feeds Ltd.  
Animix Ltd.  
Pembe Flour Mills Ltd.  
Eaglevet (K) Ltd.  
Polucon K Ltd  
Alltech Products  
Agro  Chemical and Food Company  
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 published standards, addressed to the Managing Director, Kenya Bureau of Standards, 
are welcome.  
 
 
 
 
© Kenya Bureau of Standards, 201 8 
 
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                                                                 DKS  2816 :2023 
         ICS 65.120  
© KEBS 20 23 — All rights reserved    iii  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Feed grade yeast products — Specification  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
KENYA BUREAU OF STANDARDS (KEBS)  
 
Head Office: P.O. Box 54974, Nairobi -00200, Tel.: (+254  020) 605490, 602350, Fax: (+254 020)  604031  
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, 22396        Tel.: (+254 051) 210553, 210555  
Fax: (+254  041) 229448    Fax: (+254 057) 21814  
 
  DKS  2816:20 23 
iv  © KEBS 20 23 — All rights reserved   
Foreword  
 
This standard  was prepared by Animal Feeds Technical Committee comprising of Key Stakeholders under 
the guidance of the Standards Projects Committee, and it is in accordance with the procedures of the Kenya 
Bureau of Standards.  
 
The most common yeast species used in the feed industry is Saccharomyces Cerevisiae . It is typically 
incorporated  in animal  rations to improve perf ormance.  
 
Research has demonstrated that yeast product preparations can stimulate specific groups of beneficial 
bacteria in the gut and has provided mechanistic models that can explain their effects on animal 
performance . 
 
During the preparation of this standard, assistance was derived from the following document s: 
 
Association of American Feed Control Officials (AAFCO) -2018 Publication  
 
Scientific opinion on the Safety and Efficacy of Yea -Sacc as a Feed Addi tive for cattle sheep and 
goats  (Journal )  2014 . 
 
Acknowledgement is hereby made for assistance derived from these sources . 
  
KENYA STANDARD                                                              DKS  2816 :2023 
 
© KEBS 2018 — All rights reserved    1  
 
Feed grade yeast products — Specification  
 
 
 
1 Scope and field of application  
 
This Kenya standard  specifies  requirements and methods of test for feed grade yeast products used in 
animal feeds.  
 
This standard  covers live yeast, inactive yeast (hydrolyzed/ autolyzed yeast)  yeast cell wall  and yeast 
culture . 
 
2 Normative references  
 
The following referenced documents are indispensable for the application 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.  
 
ISO 5983 -1, Animal  feeding stuffs — Determination of nitrogen content and calculation of crude protein 
content — Part 1: Kjeldahl method   
 
ISO 5985, Animal feeding stuffs — Determination of ash insoluble in hydrochloric acid   
 
ISO 6490 -1, Animal feeding stuffs — Determinati on of calcium content — Part 1: Titrimetric method  
 
ISO 6491, Animal feeding stuffs — Determination of phosphorus content — Spectrometric method   
 
ISO 6492, Animal feeding stuffs — Determination of fat content  
 
ISO 6496, Animal feeding stuffs — Determination of moisture and other volatile matter content  
content   
ISO 6865, Animal feeding stuffs — Determination of crude fibre content — Method with intermediate filtration  
 
ISO 6869, Animal feeding stuffs — Determination of the contents of calcium, copper, iron, magnesium, 
manganese, potassium, sodium and zinc — Method using a tomic absorption spectrometry  
  
ISO 5984:2022 Animal feeding stuffs — Determination of crude ash  
 
 
KS 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.  
 
KS ISO 6579 , Microbiology of food and animal feeding stuffs — Horizontal method for the detection of 
Salmonella spp.  
 
3 Terms and definitions  
 
For  the purposes of this standard  the following definitions shall apply:  
 
3.1 
active dry yeast  
 
yeast which has been dried in such a manner as to preserve a large portion of its fermenting power. It 
contains no added cereal or filler /carrier  DKS  2816 :2023 
 
2  © KEBS 20 23 — All rights reserved   
3.2 
active dry yeast with a carrier  
 
yeast which has been dried in such a manner as to preserve a large portion of its fermenting power  into 
which a base material (carrier)  has been added.  
 
3.3 
yeast culture  
 
dried product composed of yeast and the media on which it was grown, dried in such a manner as to 
preserve the fermenting activity of the yeast  
 
3.4 
autolyzed/hydrolyzed yeast  
a concentrated , non extracted,  partially soluble yeast digest   
 
5 Requirements  
 
5.1 General requirements  
 
Feed grade yeast  shall be ;  
 
a) a fine powder meal, granular or in liquid form;  
 
b) of characteristic  colour;  
 
c) free from harmful constituents, metallic objects, a dulterants, moulds, pathogenic  bacteria or insect 
infestation and free from, musty, rancid or uncharacteristic odour ; and  
 
d) free flowing without clumps , 
 
5.2  Specific requirements  
 
5.2.1 Active dry yeast  
 
The active dry yeast  shall meet  the requirements  stipulated in Table 1 when tested in accordance with the 
methods given therein . 
Table 1 — Active dry yeast requirements  
 
SL 
No. Parameter  Active dry 
yeast (with 
carrier)  
 Active dry y east 
(without carrier)  
 Test method  
i) Viable yeast cells 
(CFU)/g min.  5 x 108 1.5 x  1010 AOACa 
ii) Moisture %, max.  11 9  ISO 6496  
iii) Crude protein,% 
,min.  10 35 ISO 5983 -1 
iv) Crude fat,%, max.  13 1 ISO 6492  
v) Crude fibre,%, max .  10 Nil ISO 6865  
vi) Ash, %, max.  10 8 ISO 598 4 
a Association of Official Analytical Chemists Methods.  
 
5.2.2 Autolyzed yeast  requirements  DKS  2816 :2023 
 
© KEBS 20 23 — All rights reserved    3  
The autolyzed /hydrolyzed  yeast  shall meet the requirements stipulated in Table 2. 
 
Table 2 — Autolyzed yeast requirements  
 
SL No.  Parameter  Limit  Test method  
i) Nucleic acid %, min . 3.0 AOAC  
ii) Glucan,% , min. 20 AOAC  
iii) Mannanoligosaccharide , (MOS), %, min . 14 AOAC  
iv) Crude protein, (%), min . 35 ISO 5983 -1 
v) Moisture content,  max. 8.0 ISO 6496  
a Association of Official Analytical Chemists Methods.  
 
 
 
 
5.2.3 Yeast cell wall requirements  
 
Yeast cell wall shall meet the requirements stipulated in Table 3. 
 
Table 3 — Yeast cell wall requirements  
 
SL No. Parameter  Limit  Test 
method 
i) β-glucan, %, min . 20 AOAC  
ii) Mannanoligosaccharide , (MOS), %, min. 20 AOAC  
iii) Crude protein, (%) , min. 35 ISO 5983 -1 
iv) Total carbohydrates  40 AOAC  
v) Moisture, (%) , max.  6.0 ISO 6 496 
a Association of Official Analytical Chemists Methods.  
 
5.2.4 Yeast culture nutrient requirements  
 
The Yeast culture shall meet the requirements stipulated in Table 4 when tested in accordance with the 
methods given therein  
 
Table 4 — Yeast culture nutrient requirements  
SL No.  Yeast culture nutritional values  (dry matter basis)  Test Method  
i) Protein (%) , min. 13 ISO 5983 -1 
ii) Crude fat (%) , min. 0.4 ISO 6492  
iii) Crude fiber (%) , max. 35 ISO 6865  
iv) Ash (%) , max. 25 ISO 5984 
v) Lysine (%) , min. 0.5 ISO 139 03 
vi) Methionine (%) , min.  0.1 ISO 13903  
vii) Calcium (%) , min.  0.1 ISO 6490 -1 DKS  2816 :2023 
 
4  © KEBS 20 23 — All rights reserved  viii) Phosphorus (%) , min.  0.3 ISO 6491  
ix) Magnesium (%) , min.  0.2 ISO 6869  
x) Potassium (%) , min.  1.0 ISO 6869  
 
6 Microbiological limits  
 
Feed grade yeast shall comply with the microbiological requirements stipulated in Table 5 when tested in 
accordance with the methods given therein.  
 
Table 5 — Microbiological limits for feed grade yeast  
 
SL No. Micro -organism  Limit  Test method  
i) E. coli max  10 CFU / gram  KS ISO 16649 -2 
ii) Salmonella   Absent  in 25 g KS ISO 6579  
 
 
7  Packaging  
 
7.1  Feed grade yeast for sale shall be packed in airtight containers which are of sufficient strength and 
adequately  sealed so as to withstand reasonable handling without tearing, bursting or falling open during 
normal handling and transportation.  
  
7.2  Each  container for feed grade yeast shall be clean and free from visible indications of contamination, 
and insect infestation.  
  
8 Labelling  
 
The packages shall be securely closed and marked with the following information:  
 
a) Name of product;  
 
b) Category of animals for which it is intended;  
 
c) Net weight of the product;  
 
d) Batch number;  
 
e) Name and physical address of the manufacturer;  
 
f) Date of manufacture and expiry;  
 
g) Inclusion /feeding rate ; and 
 
h) Storage instructions.  
 
  DKS  2816 :2023 
 
© KEBS 20 23 — All rights reserved    5  
Annex A  
(informative)  
 
Possible yeast carriers  
 
The following are some of the possible yeast carriers available in the market.  
 
a) Rice bran  
b) Maize bran  
c) Maize flour  
d) Maize germ  
e) Maize grain  
f) Sunflower cake  
g) Wheat bran  
h) Wheat pollard  
i) Cotton seed meal