AFDC 16 (6177)P3                                       
 
  DRAFT TANZANIA STANDARD  
 
 
Biofortified sweet potato - Specification  
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
TANZANIA BUREAU OF STANDARDS   
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 0. Foreword 
Bio fortification  is one among the interventions strategy  proposed to combat micronutrient deficiencies 
among the society. It i s a process of increasing the density of vitamins and minerals in a crop through 
conventional plant breeding, modern biotechnology,  or agronomic practices. The identified staple 
crops include maize, beans, sweet potatoes, cassava, wheat, rice and pearl mil let. Thus when bio 
fortified products are consumed  regularly, will   improve human  health and nutrition  significantly .  
This standard of bio fortified  sweet potato has been developed to keep up with advancements of the 
bio fortification  food crops and to e nsure the safety and quality of the product traded in the markets in 
order to safeguard the heal th of the consumers.  
In reporting the result of a test or analysis made in accordance with the Tanzania standard, if the final 
value observed or calculated is t o be rounded off, it shall be done in accordance with TZS 4  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
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 1 Scope  
This  Tanzania standard specifies the requirements and methods of sampling and test for beta 
carotene bio fortified  sweet potatoes [ Ipomoea batatas (L.) Lam.]  through con ventional plant breeding  
intended for human consumption.  
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 la test edition of the referenced 
document (including any amendments) applies.  
TZS 538/EAS 38, General standard for labeling of prepackaged foods  
TZS 109, Food processing unit – Code of hygiene  
CODEX STAN 192,  General standard for food additives  
CAC/RCP 44 , Code of practice for packaging and transport of fresh fruit and vegetables  
 
CAC/RCP 53, Code of Hygienic Practice for Fresh Fruits and Vegetables  
CODEX STAN 193, Codex general standard for contaminants and toxins in food and feed  
ISO 874, Fresh fruits and v egetables – Sampling   
TZS 4 , Rounding off numerical values . 
3 Terms and definitions  
For the purposes of this standard, the following terms and definitions shall apply.  
3.1  
biofortification  
is a process that enhances the nutritional value of staple food c rops by increasing the density of 
selected micronutrients  in a crop through either conventional plant breeding,  biotechnology, or 
agronomic practices.  
Define biotechnology  
3.2 
conventional plant breeding  
is the process  of crop development that entails sc reening germplasm for available genetic diversity, 
pre-breeding parental genotypes, developing and testing micronutrient dense germplasm, conducting 
genetic studies, and developing molecular markers to lower the costs and quicken the pace of 
breeding.  
3.3  
orange fleshed sweet potato   
storage roots biofortified with beta-carotene ( provitamin A ) obtained from a plant of the species 
(Ipomoea batatas (L.) Lam ), primarily used for human consumption.  
3.4 
beta- carotene  
 an organic, strongly  coloured red -orange  pigment abundant in plants and fruits; that gives biofortified 
sweet potato  deep yellow to deep orange colour.  
  
3 
 3.5  
pro-vitamin A  
is a form  of beta -carotene that can be converted within the body into a vitamin A  
 
 
3.6 
firm 
not soft, shrivelled or flabby  
3.7 
fresh   
orange fleshed storage roots obtained from a plant of the species (Ipomoea batatas (L.),Lam)  having 
visual characteristics of colour, texture and firmness typical of just harvested sweet potato at the time 
of sale.  
3.8 
whole  
fresh storage root s which have not been subjected to any mechanical damage or peeling of its initial 
harvested mass with the exemption of trimming.  
3.9 
sound/wholesome  
free from pests, diseases, serious deterioration (such as but not limited to decay, breakdown, freezing 
damage, or softness) or adulteration/contamination, that appreciably affects their appearance, edibility 
and the keeping quality of the produce or market value.  
3.10 
practically free  
produce without defects in excess of those that can be expected to result f rom, and be consistent with 
good cultural and handling practices employed in the production and marketing of the fresh orange 
fleshed sweet potatoes.  
3.11 
clean  
practically free from dirt or staining or other foreign matter or extraneous matter  
3.12 
food g rade packaging material  
material, made of substances which are safe and suitable for their intended use and which will not 
impart any toxic substance or undesirable odour or flavour to the product.  
3.13 
extraneous matter  
organic matter of plant origin othe r than the fresh orange fleshed sweet potato  
3.14 
foreign matter  
organic and inorganic materials (such as sand, soil, glass) other than extraneous matter in the orange 
fleshed sweet potato  
4 Quality requirements  
4.1 General requirements  
Orange fleshed  swee t potatoes shall have reached an appropriate degree of physiological 
development taking into account the characteristics of the variety and the area in which they are 
grown. The biofortified sweet potatoes shall have been carefully harvested.   
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 4.2 Minimum r equirements  
Fresh orange fleshed sweet potatoes supplied to the market shall be:  
a) firm; 
b) whole;  
c) fresh;  
d) wholesome/sound;  
e) not affected by rot, mould or deterioration  as to make it unfit for consumption ; 
f) clean, and practically free of any visible extraneous mat ter or foreign matter, except permitted 
substances used to prolong its shelf life;  
g) of colour, taste and texture  characteristic of variety;  
h) practically free of pests and damage caused by pests;  
i) free of excess external moisture, adequately surface dried if  they have been washed ;  
j) free of any foreign smell and/or taste with exception of preservation agents allowed under clause 
5;  
k) free from greening   
l) free from genetic modified materials  
4.3    Biofortification requirements  
Biofortified sweet potatoes  shall comply with given limits in Table 1 when tested in accordance with 
the test methods specified therein.  
Table 1 — Requirements for Fresh Orange fleshed sweet potato  
S/N Characteristic    Baseline 
micronutrient 
content (ppm)  
 Minimum Limits 
(ppm) on dry basi s Test Method  
1 Pro vitamin A  2 32  AOAC 2001.13  
 
4.4 Quality tolerances  
Tolerances for the quality requirements shall be such that:  
a) no more than 3 % of the orange fleshed sweet potatoes may be affected by rot, mould or 
deterioration  as to make it unfit for consumption;  
b) no more than 3 % of the orange fleshed sweet potatoes may be affected by damage caused by 
pests; and  
c) no more than 3 % of the orange fleshed sweet potatoes may be affected by rot, mould or 
deterioration;  and  damage caused by pests in comb ination.   
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 5 Classification of fresh orange fleshed sweet potatoes  
5.1 Types of classes  
Fresh orange fleshed sweet potatoes may be classified before marketing.  
Where classification is done the following grades shall be used in accordance with the requireme nts 
of each class and the quality tolerances in Clause 7.  
 extra class;  
 class I; and  
 class II.  
5.2 Class requirements  
5.2.1 Extra class  
Extra class orange fleshed sweet potatoes shall meet the minimum requirements in Clause 4.2 and 
shall be:  
a) of superior qua lity in terms of texture and appearance; and  
b) characteristic of the variety and uniform in shape and size.  
Extra class orange fleshed sweet potatoes shall be free from defects, with the exception of defects on 
the surface  affecting not more than 2 % of the  orange fleshed sweet potatoes.  
5.2.2 Class I  
Class I orange fleshed sweet potatoes shall meet the minimum requirements in Clause 4.2 and shall 
be;   
a) of good quality; and  
b) uniform in shape and size that are characteristic of the variety.  
The following sligh t defects may be allowed, provided these do not affect the general appearance, the 
quality, the keeping quality and presentation of orange fleshed sweet potatoes:  
a) defects in shape not exceeding 5% of the orange fleshed sweet potatoes;  
b) bruising, not exceed ing 10% of the surface area of the orange fleshed sweet potatoes;   
c) scraped areas, not exceeding 20% of the surface area of the orange fleshed sweet potatoes; and  
d) scarred and healed damage, not exceeding 5% of the surface area of the orange fleshed sweet 
potatoes.  
5.2.3 Class II  
Class II orange fleshed sweet potatoes shall meet the minimum requirements in Clause 4.2 but may 
not qualify for inclusion in the higher classes.  
The following defects may be allowed:  
a) defects in shape not exceeding 10% of the ora nge fleshed sweet potatoes;   
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 b) bruising, not exceeding 20% of the surface area of roots  
c) scraped areas, not exceeding 30% of the surface area of orange fleshed sweet potatoes and  
d) scarred and healed damage, not exceeding 10% of the surface area of the orange f leshed sweet 
potatoes.  
6 Provisions concerning tolerances  
6.1 Quality tolerances  
Tolerances in respect of quality and size shall be allowed in each package for produce not satisfying 
the requirements of the class indicated.  
The following tolerance limits m ay be allowed for specific classes:  
(a) Extra class: 5% by weight of orange fleshed  sweet potatoes not satisfying the requirements 
of extra class, but meeting those of Class I or exceptionally coming within the tolerances of class I.  
(b) Class I: 10% by w eight of orange fleshed  sweet potatoes not satisfying the requirements of class I, 
but meeting those of Class II or exceptionally, coming within the tolerances of class II.  
(c) Class II: 20% by weight of orange fleshed  sweet potatoes not satisfying the min imum 
requirements,  with the exception of produce affected by rotting or any other deterioration rendering it 
unfit for consumption.  
6.2 Size tolerances  
For all classes, 10% by number or weight of orange fleshed sweet potatoes corresponding to the size 
abov e and/or below that indicated on the package.  
7 Size designation of fresh orange fleshed sweet potatoes  
 Fresh orange fleshed  sweet potatoes may be designated by size  and weight  as specified in  Table 2.   
Table 2 — Size for fresh orange fleshed sweet pota toes 
Size code  Size Weight, g  
A Large  >  650  
B Medium  450 - 650 
C Small  < 450  
8 Food additives  
Biofortified sweet potatoes may be preserved by use of food additives in accordance with Codex Stan 
192. 
9 Contaminants  
9.1 Pesticide residues  
Fresh orang e fleshed sweet potatoes shall conform to those maximum residue limits for pesticide 
residues established by Codex Alimentarius Commission for this commodity.   
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 9.2 Other contaminants   
Fresh orange fleshed sweet potatoes shall conform to those maximum  of lead and cadnium  levels as 
specified in  Codex General Standard for Contaminants and Toxins in Food and Feed (CODEX STAN 
193).  
10 Hygiene  
Fresh orange fleshed sweet potatoes shall be handled in hygienic manner in accordance with the 
appropriate sections TZS  109 and CAC/RCP 53.   
11 Packaging  
   Fresh orange fleshed  sweet potatoes shall be packaged in such a way to protect the produce from 
mechanical, heat and frost damage.  
Fresh orange fleshed  sweet potatoes shall be packaged in food grade packaging materia ls that will 
safeguard the hygienic, nutritional, and organoleptic qualities of the produce.  
In order to maintain produce quality during transportation and marketing, fresh orange fleshed  sweet 
potato shall be packaged and transported in accordance with th e appropriate sections CAC/RCP 44.  
12 Weights and measures  
Fresh orange fleshed  sweet potatoes shall be packaged in accordance with the weights and 
measures requirements in the destination country.  
13 Labelling  
13.1In addition to the requirements of TZS 5 38/EAS 38, the following specific requirements shall 
apply and shall be legibly  and indelibly marked:   
a) name of the produce to be shown on the label shall be “pro -vitamin A ( orange fleshed)  sweet 
potatoes”;  
b) name and location address of the vendor  and/or p acker shall be declared;  
c) country of origin of the produce;  
d) place of origin such as district, or region;  
e) commercial identification shall be declared by:  
 grade (only when classified);  
 variety;  
 size (size code); and  
 net weight (in metric system).  
f) lot ident ification (batch number);  
g) declaration of preservatives, if used;  
h) date of harvest;   
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 i) packing date;  
j) storage conditions; and  
k) Indication “for human food”.  
l) declaration that biofortified sweet potato is not genetically modified  
13.2  When labelling non -retail pack ages, information for non -retail packages shall either 
be given on the packages or in accompanying documents, except that the name of the produce, lot 
identification and the name and address of the producer or packer shall appear on the package.  
14 Samplin g and test  
Sampling shall be done in accordance with ISO 874. Tests for pesticide residues, contaminants and 
toxins shall be conducted in accordance with the recommended methods of the Codex Alimentarius 
Commission.  
15 Criteria for conformity  
A lot shall be declared as conforming to this standard if samples inspected or analysed for quality 
requirements conform to the provisions of this standard.