KENYA STANDARD  KS 1172:2022  
ICS 67.140.10  
Second  Edition  
  
 © KEBS 2022   
  Chicken eggs - Specification   
 
 
KS 1172 : 2022  
ii © KEBS 2022  – All rights reserved  
 TECHNICAL COMMITTEE REPRESENTATION  
The following organizations were represented on the Technical Committee:  
Ministry of Health - food safety unit  
Kenya Industrial Research and Development Institute  
National Public Health Laboratory  
Government Chemist’s Department  
Farmer’s Choice (K) Ltd.  
University of Nairobi — Department of Food Science, Nutrition and Technology  
Consumer Information Network  
Kenchic (K) Ltd.  
Kenya Meat Commission  
Directorate of Livestock Production  
Directorate of Veterinary Services  
Kenya Nut Company - Morendat farm  
Meat Training institute  
Choice Meats limited  
XXX 
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, 2022  
Copyrigh t. 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 Bureau of Sta ndards 
may be reproduced, stored in a retrieval system in any form or transmitted by any means without prior permission in writing f rom the 
Managing Director.   KENYA STANDARD  KS 1172 :2022  
ICS 67.140.10  
Second  Edition  
 
© KEBS 2022  – All rights reserved  iii 
   Chicken eggs - Specification   
 
Kenya Bureau of Standards,  Popo Road, Off Mombasa Road,  
P.O. Box  54974 - 00200,  Nairobi, Kenya  
 +254 020 6948000, + 254 722202137, + 254 734600471  
 info@kebs.org  
 @KEBS_ke  
 kenya bureau of standards (kebs)  
  
KS 1172 : 2022  
iv © KEBS 2022  – All rights reserved  
 Foreword  
This Kenya Standard was prepared by the Meat  and Poultry  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  
Chicken eggs are a major so urce of animal protein for human consumption in Kenya. They are not graded  prior 
to being offered for sale and consumers ae not assured of  their quality.  The Kenya Standard prescribes general 
requirements for grading fresh chicken eggs. It will assist the  producer to maintain production of good quality 
(grade) eggs. It is hoped that it wi ll also create price  ‘stratificaiton’ for eggs of different grades.  
During the preparation of this Kenya standard, reference was made to the following publications:  
Malaysian Standard: MS 680: 1980 Spification for chicken eggs.  
KS 05 -220: Methods for the m icrobiological examination of foods.  
Acknowledgement is hereby made for the assistance derived from this (these) source (s)  
 KS 1172 : 2022    
 
© KEBS 2022 – All rights reserved   
 Chicken egg s - Specification  
1 Scope  
This standard prescribes requirements and grading edible  chicken eggs  in-shell intended for human  
consumption  
2 Normative references  
The following referenced documents referred to in the text in such a way that some or all of their content 
constitutes requirements of this document. For dated references, only the edition cited applies. For undated 
references, the latest edition of the re ferenced document (including any amendments) applies , see ISO/IEC 
Directives, Part  2). 
I. KS EAS 38, Labelling of pre -packaged foods  
II. KS EAS 39, Hygiene in the food and drink manufacturing industry — Code of practice  
III. CAC/RCP 1 -1969, Rev. 4 -20031:  Recommended International Code of Practice General Principles of Food 
Hygiene  
3 Terms and definitions  
For the purposes of this document, the following terms and definitions apply.  
3.1  
air cell  — The air space between the inner and outer shell membranes found at the larger end of the  
egg. 
candling  — The process of determining the interior quality and soundness of the shell of an egg by  
the use of candling apparatus.  
check  — An egg that has a bro ken shell or crack in the shell but with its shell membrane still intact,  
and its contents do not leak.  
clean — An egg whose shell must be unbroken and is free from foreign material and from stains and  
discolorations that are readily visible.  
dirty  — An eg g whose shell must be unbroken and has adhering dirt and/or stains covering more  
than  of the shell surface.  
egg grading  — The grouping of eggs into lots having similar characteristics such as colour, weight  
and quality  
egg white or albumen  — The jelly -like substance surrounding the yolk in the egg.  
leaker — An egg that has a break or crack in the shell and shell membrane to the extent that the  
contents are exuding, or free to exude, through the shell. An egg which has a portion of the shell  
missing (in exc ess of an area 0.5 cm2) is considered a leaker even though the membrane is intact.  
loss — An egg that is inedible, smashed or broken so that the entire contents are leaking,  
contaminated or containing bloody whites, large blood spots, large unsightly meat spots or other  
foreign material.  
smashed egg — An egg whose shell is crushed or shattered,  
sound — An egg whose shell is unbroken and whose internal qualities are fit or human  
consumption.  
yolk — The yellowish spheroidal mass of food material surrounded by the white in the egg. systematic and 
functionally independent examination to determine whether quality and food safety activities and results comply  
© KEBS 2022  – All rights reserved  iii 
  with planned procedures and whether these procedures are implemented effectively and are suitable to achieve  
objectives.  
 
4 General requirements  
4.1 Classification  
For the purposes of this standard, e ggs shall be classified into two classes:  
1. Class A or “fresh” eggs are for direct human consumption and for use in food industries.  
2. Class B  eggs are for use in food industries.  
 
4.2 Minimum requirements  
The eggs shall be sound  and fit for human consumption  and shall not:  
(a) Be damaged (cracked or broken);  
(b) Have a soiled shell,  
(c) Contain visible foreign matter at candling  
(d) Have an odour  
(e) Have surface moisture  
(f) musty or mouldy  
(g) have been in an incubator  
(h) be adulterated.  
4.3 Quality Requirements  
4.3.1  Internal quality of eggs  
The candling process can be used for examining the internal quality of eggs  when required . 
The eggs shall be free from meat spots, blood spots  (aggregating not more than 0.3 cm in diameter), diffused 
blood, foreign substances and  abnormalities.  
Each egg shall have space translucent, or faintly visible, yolk in the center of the e gg when viewed  through 
candling apparatus.  
Each egg shall have a translucent and firm white, and an air space whose depth depends on the  grade of the 
egg. 
4.3.2 External Quality of eggs  
The shells of the eggs shall not be misshapen, rough, thin, cracked or broken, and shall be  reasonably free from 
stains, dirt and other foreign matter.  
4.4 Storage of eggs  
The eggs shall be freshly laid, unsoiled and stored under recommended temperatures and humidity.    
iv © KEBS 2022  – All rights reserved  
 Fresh eggs shall be eggs that are of recent pr oduction. They shall not have been held in excess of  30 days if 
kept at 15 °C and below and 14 days if kept at between 15 °C and 25 °C, and shall have  been handled under 
temperature and humidity conditions which will maintain their quality.  
 
5. Safety Requ irements  
The eggs shall be free from any pathogenic microbial organisms and from harmful contamination.  
Chicken eggs shall comply with  microbial limits given in Table 1.  
TABLE 1: MICROBIAL LIMITS TABLE  
Sl No.  Microorganism  Limits  Test Method  
n c m M  
I.  Total plate counts  5 2 5x104 106 KS ISO 4833  
II.  Coliforms  5 2 10 103 KS ISO 21528  
III.  Salmonella  10 0 0  KS ISO 6579  
 
NOTES:  
n = No. of samples  
c = the maximum  
m the value at, or below, which no concern is recognized  
M= the value below which the lot is rejected  
 
6. GRADING  
The eggs may be classified into categories based on the weight, internal quality and shell colour.  
6.1 Weight  — The eggs shall be graded as shown in Table 2.  
Table 2: Weight classification of eggs  
Category  Weight per egg (g)  
Extra large (I)  More than 61  
Large (II)  55 to 61  
Medium (III)  48 to 54  
Small (IV)  41 to 47  
Very small (V)  Less than 41  
 
6.2 Internal Quality  — There shall be four (4) major standards of quality, A, B, C and D of individual eggs   
© KEBS 2022  – All rights reserved  v 
  based on interior factors such as condition of the white and yolk, the size and condition of the air cell  and 
exterior factors of cleanliness and soundness of the shell (see Table 3).  
 
6.3 Shell Colour  
(a) White — All eggs shall b of the standard chalky white colour.  
(b) Brown — All eggs shall be brownish, including the dark cream browns, and any  
variation in the shade of brown eggshell . 
Tinted — Egg shell shall be white with brown or black spots; or brown with white or black spots.  
Eggs may be clean, dirty, check, leaker or loss, which are also descriptive terms for quality.  
Table 3: Standards or Quality of individual eggs  
Quality factor  Specification for each quality factor  
A B C D 
Shell  Clean,  
Unbroken  
Practically 
normal  Clean,  
Unbroken  
Practically 
normal  Clean to 
slightly  
Stained,  
Unbroken,  
May be slightly  
abnormal  Clean to  
moderately 
stained,  
Unbroken,  
May be 
abnormal  
Air cell  0.30 cm or less 
in 
depth, 
Practically  
regular  0.5 cm or less 
in 
depth,  
Practically 
regular  1 cm or less in  
depth  
May be 
free/loose  
bubbly  May be over 1 
cm 
in depth,  
May be free, 
loose  
or bubbly  
White  Clear,  
Clear  Clear,  
May be 
reasonably  
firm Clear,  
May be slightly  
weak  May be weak 
and 
watery,  
Shall blood 
clots or  
spots may be  
present.  
Yolk  Outline slightly  
defined 
Practically  
free from 
defects  Outline may be  
fairly well 
defined,  
Practically free  
from defects  Outline may be 
well 
defined,  
May be slightly  
enlarged and  
flattened,  
May show 
definite  
but not serious  
defects.  Outline may be  
plainly visible,  
May be 
enlarged  
and flattened,  
may show 
clearly  
visible germ  
development 
but no  
blood, May 
show  
other serious  
defects.  
 
Eggs for wholesale shall be grouped and graded in accordance with the specification given in Table  
4.  
vi © KEBS 2022  – All rights reserved  
 TABLE 4. GRADE CLASSIFICATION FOR EGGS  
GRADE  QUALITY AT LEAST  
80 % (LOT AVERAGE  
SHALL BE …)  
 TOLERANCE PERMITTED  
 
%  
 Quality  
A  
 A Not over 7  B 
B  
 B or better  Not over 7  C 
C  
 C or better  Not over 5  D Dirty or check  
 
D  D or better  Not over 5  Dirty or check  
 
The final grading of eggs shall be as shown in Table 5  
TABLE 5: Aggregate classification of eggs  
Grade  Grade Description  
AI, AII, AIII, AIV, AV  Extra Large, Large, Medium, Small,  
Very Small, with internal quality A,  
respectively.  
BI, BII, BIII, BIV, BV Extra Large, Medium, Small, very  
Small, with internal quality B,  
respectively.  
CI, CII, CIII, CIV, CV Extra Large, Large, Medium, Small,  
Very Small, with internal quality C.  
DI, DII, DIII, DIV, DV Extra Large, Large, Medium, Small,  
Very Small, with internal quality D.  
 
7. PACKING  
7.1 Eggs shall be packed with their small ends facing down. They shall be packed in cartons, cases or  
any other appropriate containers.  
7.1.1 Inner packing cartons — The cartons shall be new, standard, commercial plastic, or paper, cartons  
(or moulded trays) to suit size of grade.  
7.1.2 Outer Packing Cases — Eggs numbering 360 (30 dozens) shall be packed in nailed wooden boxes  
or fibreboard boxe s. The boxes shall be furnished with a divider forming two internal compartments.  
7.1.3 Small Packaged — Eggs shall be packed in moulded paper or plastic trays, each tray holding ½  
dozen, 1 dozen or 2½ dozen eggs.  
8. MARKING/LABELLING  
8.1 Large Packages — Each carton or case shall be suitably marked so as to give the following   
© KEBS 2022  – All rights reserved  vii 
  information.  
(i) Standard grade of the eggs;  
(ii) Number of the eggs;  
(iii) Net weight in kilograms;  
(iv) Date of collection;  
(v) Date of packing;  
(vi) Name and address of producer;  
vii) Declaration use not later than (date) if stored at 25 °C (room temperature).  
8.2 SMALL PACKAGE — Each egg tray shall have a label attached to a suitable conspicuous side so  
as to give the following information:  
(i) Standard grade of the eggs;  
(ii) Number of the eggs;  
(iii) Date of collection;  
(iv) Declaration use not later than (date) if stored 25 °C (room temperature).  
8.3 Cases for distant markets shall be marked with the declaration “EGGS HANDLE WITH CARE” in  
bold letters with an arrow pointing to the top of the case. In addition, the container shall have the  
words ‘THIS SIDE UP’ in letters 2.5 cm high.   
viii © KEBS 2022  – All rights reserved  
 Annex  A 
 APPENDIX  A 
DESCRIPTION FOR INDIVIDUAL EGGS  
A1. EXTERIOR QUALITY DESCRIPTION  
A1.1 Shell Shape and Text ure 
(i) Normal eggs shall have an oval shape with one end larger than the other.  
(ii) There shall be three (3) degrees of variation in the shape of an egg as follows:  
(a) Normal — A shell that approximates the usual shape and is of good even tester and  strength, and free 
from rough areas or this spots. Slight ridges and rough areas that  do not materially affect the shape, texture 
and strength of the shell are permitted.  
(b) Slightly abnormal — A shell that is unusual in shape or that may be slightly faul ty in texture or strength. It 
may show definite ridges but not pronounced thin spots or  rough areas.  
(c) Abnormal — A shell that is decidedly misshapen or faulty in texture or strength, or  that may show 
pronounced thin spots, ridges or rough areas.  
A1.1.1 Shell Cleanliness — The following terms shall be descriptive of shell cleanliness:  
(a) Clean — A shell that is free from foreign materials and from stains or discolourations that are  readily 
visible. An egg may be considered clean if it has only very small  specks or stains   and if such specks or stains 
are not of sufficient number or intensity to detract from the  generally clean appearance of the egg.  
(b) Moderately stained — A shell that is free from adhering dirt, but which has stains of  moderate degree 
covering not more than _ of the shell surface.  
INTERIOR QUALITY DESCRIPTION  
A2.1 Air Cell — The following terms shall be descriptive of the air cell:  
(i) Practically regular — An air cell that maintains a practically fixed position in the egg and  shows a fa irly oval 
outline with not more than 0.05 cm movement in any direction when the  egg is viewed through a candling 
apparatus.  
(ii) Free loose air cell — An air cell that moves freely towards the uppermost point if the egg is  rotated slowly. 
The shell membran es are intact by the air cell moves freely in any direction  between them.  
(iii) Bubbly air cell — A ruptured air cell resulting in one or more small separate air bubbles,  usually floating 
beneath the main air cell.  
A2.1.1 Meaning Air Cell Depth — The air cell is the air space between shell membrane, normally in the  
large end of the egg.  
Depth is the only quality factor considered for the air cell. The depth of the air cell is the distance   from its top 
to the bottom when the egg is held air cell upwards. It is measured using an official air  cell gauge at the point 
of greatest distance bet ween the top of the cell and an imaginary plane  passing through the egg at the lower 
edge of the air cell where it touches the shell (see Appendix B).  
Candling may be used together with a micrometer to measure the air cell depth.  
A2.2 Yolk — There shall be  3 factors to be considered in judging egg quality by the yolk. These are:   
© KEBS 2022  – All rights reserved  ix 
  A2.2.1 Distinctness of Yolk Shadow Outline — The term that shall be used to describe the three (3) degrees  
of distinctness of the yolk shadow outline in the standards of quality for  eggs are as follows:  
(a) Outline slightly defined — A yolk outline that is indistinctly indicated and appears to blend   into the 
surrounding white when the egg is viewed through a candling apparatus.  
(b) Outline fairly well -defined — A yolk outline that i s discernible but not clearly outlined when  the egg is 
viewed through a candling apparatus.  
(c) Outline well -defined — A yolk outline that is quite definite and distinct when the egg is  viewed through a 
candling apparatus.  
A2.2.2 Size and Shave of Yolk — The terms that shall be used to describe yolk size and shape in the  
standards of quality for eggs are as follows:  
(a) Round and firm — A yolk having the quality characteristics of newly laid eggs.  
(b) Slightly enlarged and slightly flattened — A yolk in whi ch the membranes and tissues have  weakened, 
causing it to appear slightly flattened.  
(c) Enlarged and flattened — A yolk in which the yolk membrane and tissues have weakened  and moisture 
has been absorbed from the white to such an extent that it appears definitely  enlarged and flat.  
(d) Defects and embryonic development — The terms that shall be used to describe yolk  defects are as 
follows:  
Practically free from defects — A yolk that may show no embryonic development,  but may show other very 
slight defects on its surface.  
(ii) Definite but no serious defects — A yolk that may show definite spots or areas on its  surface, but with only 
slight indications of embryonic development or other  pronounced or serious defects.  
(iii) Serious defects — A yolk t hat shows well -developed spots or areas, and other  serious defects, that do not 
render the egg inedible.  
(iv) Clearly visible embryonic development — Development of the blastodorm on the  yolk that has progressed 
to the point where it is plainly visible as a circular area or  spot but with no blood evident.  
(v) Blood due to embryonic development — Blood caused by development of the  embryo in a fertile egg to the 
point where it is visible as a definite line or as a blood  ring. 
A2.3 Egg White — The following te rms shall be descriptive of egg white:  
(i) Clear — A white that is free from discolourations or from any foreign bodies flatting  in it. 
(ii) Firm — A white that is sufficiently thick or viscous to prevent the yolk outline from  being more than slightly 
defined, or indistinctly indicated, when the egg is viewed  through a candling apparatus.  
(iii) Reasonably firm — A white that is less thick or viscous than a firm white. A  reasonably firm white permits 
the yolk to approach the shell closely, which results in  fairly well -defined yolk outline when the egg is viewed 
through a candling apparatus.  
(iv) Slightly weak — A white that is lacking in thickness or viscosity to an extent that  causes the yolk outline to 
appear well -defined when the egg is viewed through a  candling apparatus.  
(v) Weak and watery — A white that is thin and generally lacking in viscosity. A weak  and watery white 
permits the yolk to approach the shell closely, his causing the yolk  outline to appear plainly visible and dark 
when the eg g is viewed through a candling  apparatus.   
x © KEBS 2022  – All rights reserved  
 (vi) Blood clots and spots —Blood clots or spots, commonly called meat spots, may be  found on the surface of 
the yolk or floating in the white. If they are small)  aggregating not more than 0.30 cm in diameter) the egg may 
be classed as ‘D  Quality’. If larger, or showing diffusion of blood in the white surrounding them, the  egg shall 
be classed as ‘loss’.  
I.   
© KEBS 2022  – All rights reserved  xi 
  Bibliography  
[1] ISO ##### -#, General title — Part #: Title of part  
[2] ISO ##### -##:20##, General title — Part ##: Title of part  
A Bibliography , if present, shall appear after the last annex.  
The bibliography may include  
— documents that are not publicly available,  
— documents whic h are only cited in an informative manner, and  
— documents which have merely served as bibliographic or background material in the preparation of the 
document.  
For online referenced documents, information sufficient to identify and locate the source shall be provided. 
Preferably, the primary source of the referenced document should be cited, in order to ensure traceability. 
Furthermore, the reference should, as far as possible, remain valid for the expected life of the document. The 
reference shall include the method of access to the referenced document and the full network address .