ICS 67.080.20                     DMS 879:2020  
 Second edition  
 
 
 
 
 
DRAFT MALAWI STANDARD  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Fresh ware potatoes – Specification  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
NOTE: This is a draft Malawi standard and it shall neither be used or regarded as a Malawi standard  
 
__________________  
 Published by  
MALAWI STANDARDS BOARD   
 ICS 67.080.20           DMS 879:2020 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Fresh ware p otatoes  – Specification  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Obtainable from the  
Malawi Bureau of Standards  
P O Box 946  
BLANTYRE  
 
Tel: +265 870 488  
Fax: +265 870 756  
       E-mail: mbs@malawi.net  
    Website: www.mbsmw.org  
Price based on 7 pages  
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i TABLE OF CONTENTS  
 
Contents                     Page  
 
Foreword  ................................ ................................ ................................ ................................ ..............................  i 
Technical Committee  ................................ ................................ ................................ ................................ ...........  i 
Notice  ................................ ................................ ................................ ................................ ................................ ... i 
Scope  ................................ ................................ ................................ ................................ ................................ . 1 
Normative reference  ................................ ................................ ................................ ................................ ..........  1 
Terms and d efinition s ................................ ................................ ................................ ................................ ........  1 
Quality requirements  ................................ ................................ ................................ ................................ ..........  2 
Classification of fresh ware potatoes  ................................ ................................ ................................ .................  3 
Provisions  concerning s izing ................................ ................................ ................................ .............................  4 
Provisions concerning tolerances  ................................ ................................ ................................ .....................  5 
Food additives  ................................ ................................ ................................ ................................ ...................  6 
Contaminant s ................................ ................................ ................................ ................................ .....................  6 
Hygiene  ................................ ................................ ................................ ................................ ..............................  6 
Packaging  and labelling  ................................ ................................ ................................ ................................ ..... 6 
Sampling  ................................ ................................ ................................ ................................ ............................  7 
 
FOREWORD  
 
This draft Malawi standard was  prepared by MBS/TC 53, the Technical Committee on Root and tuber crops 
and their products , to provide the requirements and methods of sampling and test for fresh ware potato tuber s.  
 
This draft standard  is a result of the first review of MS 879:2013 . The revision of this standard is being done in 
order to align it with the changes which have been made to  the requirements of fresh ware potatoes.  
 
In prepar ing this draft Malawi standard, reference was made to the following standard : 
 
East African  Standard , EAS 748 :2016, Fresh ware potatoes  – Specification . 
 
Acknowledgement is made for the use of the information.  
 
 
TECHNICAL COMMITTEE  
 
This draft Malawi standard was  prepared by MBS/TC 53, the Technical Committee  on Root and tuber crops 
and their products and the following companies, organizations and institutions we re represented : 
 
Blantyre City Council;  
International Potato Center Malawi;  
Lilongwe University of Agriculture and Natural Resources;  
Malawi Bureau of  Standards;  
Ministry of Agriculture, Irrigation and Water Development – Bvumbwe Agricultural Research Station;  
Ministry of Industry – Department of S mall and Medium Enterprise s and Cooperatives  
Peoples Trading Centre;  
Shoprite Trading Limited;  
Tehilah Bake ry; and  
University of Malawi – The Polytechnic.  
 
 
NOTICE  
 
This standard shall be reviewed every five years, or earlier when it is necessary, in order to keep abreast of 
progress. Comments are welcome and shall be considered when the standard is being reviewed.  1 
                  DMS 879:2020 
 
DRAFT MALAWI STANDARD  
 
Fresh ware p otatoes  – Specification  
 
1 SCOPE  
 
This draft Malawi standard  specifies the requirements and methods of sampling and test for fresh  ware potato 
tuber of varieties (cultivars) grown from ( Solanum tuberosum L.) of the family Solanaceae  for human 
consumption. It does not cover the requirements for seed potato tuber . 
 
 
2 NORMATIVE  REFERENCE  
 
The following standards contain provisions, which through reference in this text, constitute provisions of this 
draft standard . All standards are subject to revision and, since any reference to a standard is deemed to be a 
reference to the latest edition of that standard, parties to agreements based on this draft standard  are 
encouraged to take steps to ensure the use of the most  recent edition of the standard s indicated below. 
Information on current valid national and international standards can be obtained from the Malawi Bureau of 
Standards.  
 
MS 19 : Labelling of prepackaged foods – General standard;  
 
MS 237 : Food additives – General standard;  
 
MS 302 : Contaminants and toxins in foods – General standard;  
 
MS 1520 : Fresh fruits and vegetables – Sampling ;  
 
MS 1 603: Production and handling of fresh ware potatoes – Code of practice; and  
 
ISO 7558: Guide  to the prepacking of fruits and vegetables . 
 
 
3 TERMS AND DEFINITION S 
 
For the purpose s of this draft Malawi standard , the following terms d efinitions shall apply . 
 
3.1 
black heart   
blackening of tissues in the centre  of the potato  
 
3.2   
badly misshapen   
potato tuber that is seriously deformed relative to the varietal shape   
 
3.3   
clean   
practically free from dirt or staining and practically no loose dirt or other foreign matter present in the container   
 
3.4 
damaged  
any defect or inj ury which is readily apparent upon examination ,or which affects the edible quality  of the potato 
tuber  
 
 
  
2 3.5 
defects  
defects which can be detected externally. However, cutting may be required to determine the extent of the   
injury.  
 
3.6 
firm 
not soft, flabby or shrivelled  
 
3.7 
food grade material  
one that will not transfer non -food chemicals into the food and contains no chemicals which would be  
hazardous to human health  
 
3.8 
foreign matter  
any material other than that originating from the potato tuber  
 
3.9 
hollow heart  
cavities of various sizes in the centre of the tuber  
 
3.10 
intact  
not having any part removed or damaged such that it makes the potato tuber incomplete  
 
3.11 
similar varietal characteristics  
potato tuber that are of the same variety and t ype. 
 
3.12 
sprout  
new shoot emerging from the tuber  
 
3.13 
sound  
free from disease, serious deterioration (such as but not limited to decay, breakdown, freezing damage, or soft 
or shriveled specimens) or adulteration/contamination, that appreciably affects their appearance, edibility  
 
 
4 QUALITY REQUIREMENTS  
 
4.1 General requirements  
 
4.1.1  The fresh ware potato tubers should be carefully harvested after reaching an appropriate degree of 
physiological development  and maturity  taking into account the characteristics of the variety and the area in 
which they are grown.   
 
4.1.2  The development and condition of the fresh ware potato tuber shall be such as to enable it to:  
 
4.1.2.1  Withstand normal transport and handling condition;  and 
 
4.1.2.2  Arrive in a satisfactory condition at the place of destination.  
 
4.2 Specific requirements  
 
All fresh ware potato tubers to be supplied to the market , subject to tolerance s allowed , shall be: 
 
4.2.1 Practically clean, sound, firm and intact;  
 
4.2.2  Of normal appearance for similar varietal characteristics , according to the producing area ; 
 
4.2.3  Free of abnormal external moisture, i.e. adequately “dried” if they have been washed;   
3 4.2.4  Free of any foreign smell and/or taste;  
 
4.2.5  Practically unsprouted, i.e. sprouts may be no longer than 3 mm;  
 
4.2.6  Free of loss of colour such as browning in flesh;  
 
4.2.7  Be free from pest damage affecting the general appearance of the produce;  
 
4.2.8  Practically free from mechanical damage;  
 
4.2.9  Covered with well -formed skin, i.e. the skin has to be fully developed and mature and cover the whole 
surface of the tuber;  
 
4.2.10  Free from waste, i.e. attached or loose earth, detached growth shoots, extraneous matter.  
 
4.2.11 Free of external or internal defects detrimental to the general appearance of the  produce, the quality, 
the keeping quality and presentation in the package, such as:  
 
4.2.11.1 Brown stains due to heat ; 
 
4.2.11.2 Cracks (including growth cracks), cuts, bites, bruises or roughn ess (only for  varieties of which the skin 
is not normally rough) exceeding 4 mm in depth;   
 
4.2.11.3 Green colouration; pale green flush not exceeding one eighth of the surface  area and which can be 
removed by normal peeling does not constitute a  defect ; 
 
4.2.11.4 Serious deformities (i.e., malformation, `bad misshape ); 
 
4.2.11.5 Grey, blue or black sub -epidermal stains; exceeding 5 mm in depth ; 
 
4.2.11.6 Rust stains, hollow or black hearts and other internal defects ; 
 
4.2.11.7 Deep common potato scab and powdery potato scab, of a depth of 2 mm or  more ; 
 
4.2.11.8 Superficial common potato scab, i.e. scab spots in all must not extend over  more than a quarter of 
the surface of the tuber ; and 
 
4.2.11.9 Rost damage and freezing injuries . 
 
 
5 CLASSIFICATION OF FRESH WARE POTATOES  
 
5.1 Types of classes   
 
Fresh ware potatoes may be classified before marketing. Where classification is done the following grades 
shall be used in accordance with the requirements of each class and the quality tolerances in clause 7.  
 
5.1.1  Extra class;  
 
5.1.2  Class I; and  
 
5.1.3  Class II.  
 
5.2 Class requirements  
 
5.2.1  Extra class  
 
5.2.1.1  Fresh ware potato tuber s shall be tubers that meet specific requirements in clause 4.2 and are:  
 
a) Of superior quality ; and  
b) Characteristic of the variety  and /or commercial type  
5.2.1.2  Fresh ware potato tubers shall be free of defects with exception of very slight superficial bruises   
4 provided that this will not affect the general appearance of the produce, the keeping quality and the 
presentation in the package.   
 
5.2.2  Class I  
 
5.2.2.1  Fresh ware potato tuber s shall be tubers that meet specific requirements in clause 4.2 and are  
 
a) Of good quality ; and  
 
b) Characteristic of the variety and commercial type.  
 
5.2.2.2  The following slight defects however may be allowed provided that this will not affect the general 
appearance of the produce, the keeping quality and the presentation in the pack age:  
a) Slight defects in shape and colour ; 
b) Slight skin defects such as scratches, scars, scrapes and blemishes and shall not exceed 5 % of the 
surface area of an individual tuber ; 
c) Defects shall not in any case affect the flesh of the produce ; 
d) Bruising, not exceeding 10 % of the surface area of the tubers ; and  
e) The deep common potato tuber scab and powdery tuber scab should not extend more than 3 % of the 
surface area and intrusion not exceeding 2 mm .  
 
5.2.3  Class II  
 
This class shall compris e fresh potato tuber of marketable quality, which do not qualify for inclusion in the other 
classes. The following defects may occur provided the fresh potato tuber retain their essential characteristics 
as regards to quality, keeping quality and presentat ion:   
 
5.2.3.1  Defects in shape not exceeding 10  % of the tubers ; 
 
5.2.3.2  Cured bruises, not exceeding 20 % of the surface area of the tubers ; 
 
5.2.3.3  Lesions not more than 2 mm in depth and covering not more than 5% of the surface area of the tuber;   
 
5.2.3.4  Sub-epidermal stains not more than 2 mm in depth; and 
 
5.2.3.5  Internal defects in not more than 3 % by number or mass of the tubers . 
 
 
6 PROVISIONS CONCERNING SIZING  
 
6.1 Fresh ware potato tuber may be designated by size in accordance with Table 1. The size of the tuber 
shall be determined by use of an appropriate square mesh.  
 
Table 1 – Scale for sizing fresh ware potato tubers  
 
1 2 3 4 
S/N Size Minimum (mm)  Maximum (m/m)  
1 Small  31 x 31  50 x 50  
2 Medium  51 x 51  80 x 80  
3 Large  51 x 51  81 x 81 
  
5 6.2 Fresh ware potatoes exceeding the maximum size shall be allowed, provided the maximum difference 
in size between the smallest and the largest tuber is not more than 30 mm and they are marketed under a 
specific denomination.  
 
6.3 Tubers of a size range between 18 mm and 35 mm can be marketed under the denomination of "mids" 
or an equivalent denomination.  
 
6.4 Uniformity in size is not compulsory. However, in sales packages up to 5 kg net weight, the maximum 
difference allowed between the smallest a nd the largest tuber must not exceed 30 mm.  
 
6.5 The sizing requirements do not apply to long varieties of irregular shape (e.g. Stella, Ratte , Rosetta or 
Violet ). 
 
 
7 PROVISIONS CONCERNING TOLERANCES  
 
At all marketing stages, tolerances in respect of quality , class , size and variety  shall be allowed in each lot for 
produce not satisfying the specific  requirements.  
 
7.1 Quality tolerances  
 
The following are the quality tolerances that shall be allowed:  
 
7.1.1  6 % by weight of tubers of fresh ware potato t ubers not satisfying the specific  requirements shall be 
allowed . However, within this tolerance, a maximum of 1 % by weight of tubers affected by dry or wet rot shall 
be allowed.  
 
7.1.2  In addition , fresh ware potatoes with  2 % by weight of waste,  of which a maximum of 1 % is attached 
earth, s hall be allowed.  
 
7.2 Class tolerances  
 
7.2.1  Extra class  
 
Fresh  ware  potato tuber of extra class may have a maximum of 5 % by number or mass of potato tuber not  
satisfying the requirements of the class, but meeting those of Class I or exceptionally coming within the 
tolerances of that class.  
 
7.2.2  Class I  
 
Fresh ware potato tuber of class I may have a maximum of 10 % by number or mass of potato tuber not 
satisfying the quality requirements of Class II, but meeting those of Class III or exceptionally coming within the  
tolerances of that class.  
 
7.2.3  Class II 
 
Fresh  ware  potato tubers of Class II shall satisfy the specific  quality requirements.  They m ay have a  maximum 
of 10 % by number or mass of potato tuber  not satisfying the quality requirements.  
 
7.3 Size tolerances  
 
A total tolerance of 10 %, by weight of tubers, not satisfying the requirements as regards sizing shall be  
allowed.  
 
7.4 Tolerances of other varieties  
 
A tolerance of 2 % by weight of other varieties shall be allowed.   
6 8 FOOD ADDITIVES  
 
Fresh ware potatoes may be preserved by use of food additives in accordance with MS 237.  
  
 
9 CONTAMINANTS  
 
9.1 Pesticide residues  
 
Fresh ware potatoes shall comply with the maximum residue limits for pesticides established by the Codex 
Alimentarius Commission for this commodity.  
 
9.2 Heavy metals  
  
Fresh ware potatoes shall comply with those maximum levels for heavy metal contaminants established by the 
Codex Alimentarius Commission for this commodity.  
 
 
9.3 Other contaminants  
 
Fresh ware potatoes shall comply with the maximum levels of contaminants and toxins in MS 302. 
 
 
10 HYGIENE  
 
Fresh ware potatoes shall be handled a hygienic manner complying with MS 1603.   
 
 
11 PACKAGING AND LABELLING  
 
11.1 Packaging  
 
11.1.1  In addition to requirements of the packaging section in MS 1 603, the following specific requirements 
should be met:  
 
11.1.2  Fresh potato tubers shall be packed in containers in accordance with ISO 7558.  
 
11.1. 3 When packed, the contents of each package shall be uniform and consist exclusively of potato tubers 
of the same origin, variety and/or commercial  type, and quality. The visible part of the content of the package 
shall be representative of the entire contents.  
 
11.1.4  For uniformity, the  contents of each package (or lot for produce presented in bulk in the transport 
vehicle) must be uniform and contain only early or ware potatoes of the same origin, variety, quality, colour of 
the skin, colour of the flesh and size (if sized) . 
 
11.1.5  The visible part of the contents of the package must (or lot for produce presented in bulk in the transport 
vehicle) be representative of the entire contents.  
 
11.2 Labelling  
 
11.2.1  In addition to the requirements of MS 19, the following specific requirements shall apply and shall be 
legibly and indelibly marked : 
 
11.2.1. 1 Name, postal and physical address of the producer/packer or dispatcher ;  
 
11.2.1.2  Name of the produce as " Fresh ware potatoes " ; 
 
11.2.1 .3 Name of the variety ; 
 
11.2.1 .3 Specific denomination for ware potatoes exceeding maximum size, where appropriate ; 
 
11.2.1 .4 “Mids” or an equivalent denomination, where appropriate ; 
  
7 11.2.1.5  Place  of origin  and, optionally, district where grown, or national, regional or local place name ; 
 
11.2.1.6  Harvest date  
 
11.2.1. 7 Commercial identification shall be declared by:  
 
11.2.1. 7.1 Grade only when classified;  
 
11.2.1. 7.2 Variety /cultivar or type;  
 
11.2.1. 7.3 Size (if sized) expressed as minimum size followed by the words “and over” or as minimum and 
maximum size ; 
 
11.2.1.7.4  Class;  
 
11.2.1.7.5  Optional indications: colour of flesh (e.g., yellow or white), colour of skin, shape of tuber (round or 
long) and cooking type (e.g., floury or firm) ; and  
 
11.2.1. 7.6 Net weight (in metric system) . 
 
11.2.1.8   Identification code and/or batch number ; and  
 
11.2.1.9   Storage instructions . 
 
11.2.2 When labelling non -retail packages, information for non -retail packages shall either be given on the 
packages or in accompanying documents, except that the name  of the product, lot identification and the name 
and address of the manufacturer or packer shall appear on the package.  
 
 
12 SAMPLING  
 
Representative samples of fresh ware potatoes shall  be sampled in accordance with MS 1520.  
 
 
 
  
 
 
ICS 67.080.20                                        DMS 879:2020  
 
 
 
 
 
 
THE MALAWI BUREAU OF STANDARDS           CERTIFICATION MARK  SCHEME  
The Malawi Bureau of Standards is the 
standardizing body in Malawi under the aegis 
of the Ministry of Industry and Trade.  Set up 
in 1972 by the Malawi Bureau of Standards 
Act (Cap: 51:02), the Bureau is a parastatal 
body whose activities aim at formulating and 
promoting the general adoption of standards 
relating to structures, commodities, materials, 
practices, operations and from time to time 
revise, alter and amend the same to 
incorporate advanced technology.  To bring the adva ntages of standardization 
within the reach of the common consumer, the 
Bureau operates a Certification Mark Scheme. 
Under this scheme, manufacturers who 
produce goods that conform to national 
standards are granted permits to use the 
Bureau’s “Mark of Quali ty” depicted below on 
their products.  This Mark gives confidence to 
the consumer of the commodity’s reliability.