UGANDA STANDARD
 
  US ISO 5559
     First Edition
        2009-09-04
 
Reference numbe r 
     US ISO 5559:1995
 © UNBS 2009
  
Dehydrated onion (Allium cepa  Linnaeus) — Specification 
 US ISO 5559:1995 
 
© UNBS  2009 – All rights reserved ii Compliance with this standard does not, of itself confer immunity from legal obligations 
A Uganda Standard does not purport to include all necessary provisions of a contract. Users are 
responsible for its correct application  
© UNBS 2009 
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilised in any 
form or by any means, electronic or mechanical, in cluding photocopying and microfilm, without prior written 
permission from UNBS. 
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The Executive Director 
Uganda National Bureau of Standards 
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Uganda 
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E-mail: unbs@infocom.co.ug
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   US ISO 5559:1995  
© UNBS  2009 - All rights rese rved                iii National foreword 
Uganda National Bureau of Standards (UNBS) is a parastatal under the Ministry  of Tourism, Trade and 
Industry established under Cap 327, of the Laws of U ganda. UNBS is mandated to co-ordinate the elaboration 
of standards and is  
(a) a member of International Organisation for Standardisation (ISO) and  
(b) a contact point for the WHO/FAO Codex A limentarius Commission on Food Standards, and  
(c) the National Enquiry Point on TBT/SPS Agr eements of the World Trade Organisation (WTO). 
The work of preparing Uganda Standards is carried out through Technical Committees. A Technical 
Committee is established to deliberate on standards in a gi ven field or area and consists of representatives of 
consumers, traders, academician s, manufacturers, governme nt and other stakeholders. 
Draft Uganda Standards adopted by the Technical Committ ee are widely circulated to stakeholders and the 
general public for comments. The committee reviews the comments before recommending the draft standards 
for approval and declaration as Uganda Standards by the National Standards Council. 
This Uganda Standard, US ISO 5559, Dehydrated onion (Alliu m cepa Linnaeus) — Specification,
is identical with and has been reproduced from an International Standard, ISO 5559:1995,  Dehydrated 
onion (Allium cepa Linnaeus) — Specification, and adopted as a Uganda Standard.
  This standard was developed by the Food and agricu lture Standards Technical Committee (UNBS/TC 2).  
Wherever the words, "International Standard" a ppear, they should be replaced by "Uganda Standard." 
 INTERNATIONAL 
STANDARD ISO 
5559 
Third edition 
1995-09-01 
Dehydrated onion (Allium cepa 
Linnaeus) - Specification 
Oignon dbshydrat6 (Allium cepa Linnaeus) - Spkifications 
Reference number 
ISO 5559: 1995(E) ISO 5559: 1995(E) 
Foreword 
ISO (the International Organization for Standardization) is a worldwide 
federation of national Standards bodies (ISO member bodies). The work 
of preparing International Standards is normally carried out through ISO 
technical committees. Esch member body interested in a subject for 
which a technical committee has been established has the right to be 
represented on that committee. International organizations, governmental 
and non-governmental, in liaison with ISO, also take part in the work. ISO 
collaborates closely with the International Electrotechnical Commission 
(IEC) on all matters of electrotechnical standardization. 
Draft International Standards adopted by the technical committees are 
circulated to the member bodies for voting. Publication as an International 
Standard requires approval by at least 75 % of the member bodies casting 
a vote. 
International Standard ISO 5559 was prepared by Technical Committee 
lSO/TC 34, Agricultural food products, Subcommittee SC 7, Spices and 
condimen ts. 
This third edition cancels and replaces the second edition 
(ISO 55599 983), which has been technically revised. 
Annex A forms an integral part of this International Standard. Annexes B, 
C, D and E are for information only. 
0 ISO 1995 
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced 
or utilized in any form or by any means, electronie or mechanical, including photocopying and 
microfilm, without Permission in writing from the publisher. 
International Organization for Standardization 
Case Postale 56 l CH-l 211 Geneve 20 l Switzerland 
Printed in Switzerland 
ii INTERNATIONAL STANDARD 0 ISO ISO 5559: 1995(E) 
Dehydrated onion (ANium cep Linnaeus) - 
Specification 
1 Scope 
1 .l This International Standard specifies require- 
ments for dehydrated onion (Allium cepa Linnaeus) in 
its various commercial forms. 
NOTE 1 The main commercial forms are given in 
annex B, for information only. 
1.2 Recommendations relating to microbiological 
requirements are given in annex C, without prejudice 
to the national legislation applicable in different 
countries. 
1.3 Recommendations relating to storage and trans- 
port are given in annex D. 
2 Normative references 
The following Standards contain provisions which, 
through reference in this text, constitute provisions 
of this International Standard. At the time of publi- 
cation, the editions indicated were valid. All Standards 
are subject to revision, and Parties to agreements 
based on this International Standard are encouraged 
to investigate the possibility of applying the most re- 
cent editions of the Standards indicated below. 
Members of IEC and ISO maintain registers of cur- 
rently valid International Standards. 
ISO 927: 1982, Spices and condiments - Determi- 
nation of extraneous matter tonten t. 
ISO 928:1980, Spices and condiments - Determi- 
nation of total ash. 
ISO 930:1980, Spices and condiments - Determi- 
nation of acid-insoluble ash. 
ISO 948: 1980, Spices and condimen ts - Sampling. ISO 1026:1982, Fruit and vegetable products - De- 
termination of dry matter content by drying under re- 
duced pressure and of water content by azeotropic 
dis tilla tion. 
ISO 1208:1982, Spices and condiments - Determi- 
na tion o f filth. 
ISO 5498: 1981, Agricultural food products - Deter- 
mination of crude fibre con ten t - General method. 
3 Definitions 
For the purposes of this International Standard, the 
following definitions apply. 
3.1 dehydrated onion: Finished product obtained 
on dtying the bulbs of any onion cultivars (Allium cepa 
Linnaeus) without any bleaching or precooking, the 
bulbs being Sound and practically free from moulds, 
diseases, soil, outer skins, Sterns, leaves and roots. 
3.2 extraneous matter: Vegetable matter originat- 
ing exclusively from plants, such as particles from 
skins and roots. 
4 Requirements 
4.1 Organoleptic specifications 
4.1.1 General 
The dehydrated onion shall conform to the require- 
ments of this International Standard and on rehy- 
dration shall regain characteristics similar to those of 
fresh onion. 
4.1.2 Colour 
The colour of the dehydrated onion shall be charac- 
teristic of the cultivar used, that is, between white ISO 5559: 1995(E) 
and cream when the product has been prepared from 
white and yellow onions, and between pink and red 
when red onions have been used. 
The product shall be practically free from scorched, 
toasted and baked particles. 
4.1.3 Odour 
The odour of the dehydrated onion shall be charac- 
teristic, and free from foreign odours and off odours. 
4.1.4 Flavour 
Since the flavour of the dehydrated onion tan be as- 
sessed only after rehydration, apply the method de- 
scribed in annex A, and then proceed with the 
sensory evaluation. 
The flavour shall be characteristic of parboiled onions 
and free from foreign flavours and off flavours. 
4.2 Freedom from insects, moulds, etc. 
Dehydrated onion shall be free from living insects, and 
practically free from moulds, dead insects, insect 0 ISO 
fragments and rodent contamination visible to the 
naked eye (corrected, if necessary, for abnormal vi- 
sion) or with such magnification as may be necessary 
in any particular case. If the magnification exceeds 
x 10, this fact shall be mentioned in the test report. 
In cases of dispute, the contamination of onion in 
powder form shall be determined by using the 
method specified in ISO 1208. 
4.3 Extraneous matter 
The total percentage of extraneous matter, as defined 
in 3.2 and determined in accordance with ISO 927, 
shall not exceed the value given in table 1. 
4.4 Classification 
Dehydrated onion is classified according to its colour, 
presentation and extraneous matter content in ac- 
cordante with the requirements given in table 1. 
4.5 Chemical requirements 
Dehydrated onion shall comply with the requirements 
specified in table 2. 
Table 1 - Classification of dehydrated onion 
Type of onion 
Characteristic 
Extraneous matter, 
% (d..), max. White 
Extra 
0,5 Extra 
1 Yellow 
1 
2 Categories 
2 
5 Extra 
1 Red 
1 
2 2 
5 
Table 2 - Chemical requirements 
Characteristic Requirement Test method 
Moisture content, % (m/m), max. 6 ISO 1026 1) 
Total ash, % (m/m), on dry basis, max. 5 ISO 928 
I Acid-insoluble ash, % (m/m), dry basis, max. I 015 ISO 930 I 
Crude fibre content, % (m/m) max. 30 ISO 5498 
1) This method to determine the moisture content is used because of the high sugar content of onions; a magnetic stirrer 
should be used to keep the test Portion suspended in the liquid and thus avoid the danger of frothing and caramelization. I 0 ISO ISO 5559: 1995(E) 
5 Sampling 
5.1 Dehydrated onion powder, grits, flakes 
or granules 
Sample the product in accordance with ISO 948, us- 
ing a conical Sampler or other suitable implement to 
remove aseptically a representative Sample. 
5.2 Dehydrated onion slices 
Certain Problems arise as a result of the friability of 
the product and the danger of settling within the 
Container. lt may therefore be necessary to take the 
entire contents of a Single Container because, during 
transport, the onion may settle with larger pieces 
towards the top and smaller pieces towards the bot- 
tom. 7 Packing and marking 
7.1 Packing 
Dehydrated onion shall be packed in clean, Sound and 
dry Containers made of a material which does not af- 
fett the product but which protects it from light and 
from the ingress of moisture. 
7.2 Marking 
b) 
The principles of the method described in ISO 948 
apply with the modifications given in 5.2.1 and 5.2.2. The following particulars shall be marked directly on 
each package or shall be marked on a label attached 
to the package: 
a) name of the product and botanical name and 
tradename, if any; 
name and address 
trademark, if any; of the Producer or packer, or 
c) code or batch number; 
5.2.1 Number of Containers to be taken 
d) net mass; 
Take from the lot between 0,5 % and 1,O % of the 
Containers, using a table of random numbers agreed 
between the interested Parties. If no table of random 
numbers is available, take every nth Container. 
5.2.2 Preparation of bulk Sample 
Sieve the contents of each Container according to the 
commercial form considered (see annex B). Prepare 
the bulk Sample by mixing portions of the different 
sieved fractions in the proportions determined by 
sieving. The size of the bulk Sample shall be at least 
three times the quantity of product necessary to carry 
out all the tests required by this International Stan- 
dard. 
6 Test methods e) producing country; 
f) any other information requested by the purchaser, 
such as year of production and date of packing, if 
known; 
g) reference to this International Standard; 
h) whether the product contains additives, and 
which ones, in the case of countries where they 
are permitted. 
Samples of dehydrated onion shall be tested for con- 
formity with the requirements of this International 
Standard using the test methods specified in 4.2, 
4.3, 5.1, 5.2 and table 2. 
3 ISO 5559:1995(E) 
Annex A 
(normative) 
Method of rehydration for sensory evaluation of dehydrated onion 
A.1 Apparatus 
A.l.l Vessel, of about 500 ml capacity, which will 
not impart a foreign taste or affect the colour of the 
preparation. 
A.1.2 Dish, made of porcelain or white earthen- 
Ware. 
A-l.3 Stainless steel spoon 
A.2 Water 
Use natura1 potable water, as neutral as possible. 
A.3 Preparation 
Weigh 5 g + 0,l g of the Sample and transfer it to the - vessel (A.l .l) containing 250 ml of cold water (A.2). 
Bring to the boil and immediately turn off the 
heat Source. Leave to Simmer in this way for 
IO min + 1 min. Re-adjust the volume to about 
250 ml with water (A.2) and pour into the dish 
(A.1.2). 
Immediately carry out sensory evaluation by evaluat- 
ing the different characteristics in the following Order: 
- appearence of the cooking water (colour, clarity); 
- colour of the preparation; 
- odour; 
- tenderness (in the case of onion in pieces); 
- Overall flavour. ISO 5559: 1995(E) 
Annex B 
(informative) 
Commercial forms of dehydrated onion 
B.1 General information B.2.1 
The various commercial forms of dehydrated onion 
are all produced by slicing peeled Sound onions into 
flat slices (of a thickness agreed between the 
interested Parties), which are dehydrated, graded and 
further processed as necessary. Product 
moving 
B.2.2 
n I I obtained by cutting onions into slices and re- 
broken pieces smaller than 4 mm by sieving. 
Dehydrated grits, flakes or granules 
B.2 Commercial forms sizel) from 400 Pm to 4 mm according to the case. 
The particles do not have any definite shape. uenyarated onion passing through a sieve of aperture Dehydrated onion slices or rings 
The following broad categories are recognized in the 
trade, although commercial contracts may include re- 
quirements for particle size. B.2.3 Dehydrated onion powder 
Dehydrated onion of which 99 % Passes through a 
sieve of aperture sizel) 400 Pm. 
1) For determining particle size, see ISO 565. 
5 ISO 5559: 1995(E) 
Annex C 
(informative) 
Recommendations related to microbiological characteristics 
C. 1 Microbiological characteristics 
Tests conducted in the laboratories representing the Producers and the users of this product have shown that the 
microbiological characteristics given in tables Cl.1 and C.2 tan be considered as acceptable. They are given for in- 
formation only. 
C.2 Interpretation 
Take five samples. 
a) The lot shall be considered as satisfactory if: 
- all the results are < m, or 
- if two results at most are between m and 3m. 
b) The lot shall be considered as acceptable if: 
- two results at most are between 3m and M (the others being < m). 
c) The lot shall be considered as not acceptable if: 
- more than two results out of five are between m and M (the others being < m), or 
- if values above M are observed. 
Table C.1 - Microbiological characteristics of white, yellow and red dehydrated onions, 
categories Extra and 1 
Characteristic Recommended specification 
I Test method 
I m I it4 I 
Microorganisms at 30 “C, 
per gram, max. 105 106 ISO 4833 
Presumptive Escherichia 
coli, per gram, max. 10 102 ISO 7251 
Yeasts and moulds at 25 “C, 
per gram, max. 103 104 ISO 7954 
Clostridium perfringens, per 10 102 ISO 7937 
gram, max. 
Staphylococcus aureus, 
in 1 g Absent ISO 6888 
Salmonella, in 25 g Absent ISO 6579 0 ISO ISO 5559: 1995(E) 
Table C.2 - Microbiological characteristics of yellow and red dehydrated onions, category 2 
Characteristic Recommended specification 
Test method 
m A4 
Microorganisms at 30 “C, 3 x 105 3 x 106 ISO 4833 
per gram, max. 
Presumptive Escherichia 
CO/;, per gram, max. 10 102 ISO 7251 
Yeasts and moulds at 25 "C, 
per gram, max. 103 104 ISO 7954 
Clos tridium perfringens, per 
gram, max. 10 102 ISO 7937 
Staphylococcus aureus, 
in 1 g Absent ISO 6888 
Salmonella , in 25 g Absent ISO 6579 
7 ISO 5559:1995(E) 
Annex D 
(informative) 
Recommendations relating to storage and transport conditions 
D.l Storage D.2 Transport 
Packages of dehydrated onion should be stored in 
covered premises, well protected from the sun, rain 
and excessive h\eat. The storeroom should be dry, 
free from unpleasant odours and protected against 
the entry of insect.s and other vermin. The Containers should be clearly marked with a 
warning against careless handling which might lead 
to Perforation of the Containers. They should be kept 
dry and cool and stored well away from ships’ boilers 
or bilges. ISO 5559: 1995(E) 
Annex E 
(informative) 
Bibliography 
Cl] ISO 565:1990, Test sieves - Adetal wire cloth, 
perforated metal plate and electroformed sheet 
- Nominal sizes of openings. 
[2] ISO 4833: 1991, Microbiology - General guid- 
ante for the enumeration of micro-organisms 
- Colony count technique at 30 “C. 
[3] ISO 6579: 1993, Microbiology - Genera/ guid- 
ante on methods for the detection of 
Salmonella. [S] ISO 7251 :1993, Microbiology - General guid- 
ante for enumeration of presump tive 
Escherichia coli - Most probable number tech- 
nique. 
[6] ISO 7937:1985, Microbiology - Genera/ guid- 
ante for enumeration of Clostridium perfringens 
- Colon y count technique. 
[7] ISO 7954: 1987, Microbiology - General guid- 
ante for enumeration of yeasts and moulds - 
Colon y count technique at 25 o C. 
[4] ISO 6888: 1983, Microbiology - General guid- 
ante for enumeration of Staphyococcus aureus 
- Colon y coun t technique. ISO 5559:1995(E) 
ICS 67.220.10 
Descriptors: agricultural products, vegetables, dried foods, onions, classification, specifications, organoleptic properties, Chemical 
properties, marking, packaging. 
Pwe based on 9 pages