AFDC 19  (1127) DTZS  
                               
 
DRAFT TANZANIA STANDARD  
 
                 Raw Walnut  Kernels  – Specification  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
TANZANIA BUREAU OF STANDARDS   
                                                                                                             AFDC 19  (1127) DTZS  
 Raw walnut  kernels – Specification  
 
0 Foreword  
 
Walnut ( Juglans regia  L.) is consider ed as a high -quality food with human health benefits because 
walnut kernels are rich in proteins, unsaturated fatty acids, phospholipids, vitamins, minerals, essential 
fatty acids, and other nutrients. Walnuts are most often eaten on their own as a snack b ut can also be 
added to salads, pastas , breakfast cereals, soups, baked goods  and other different food products.  
 
This Tanzania standard lays down specifications aiming at ensuring the safety and quality of raw 
walnut  kernels  produced  or traded in  and out side the country for human consumption.  
 
In preparation of this Tanzania standard considerable help was derived from:  
UNECE STANDARD DPP -02  Walnut  kernels  published by the United Nations,  New York and 
Geneva,2019 .   
In reporting the results of a test or analysis made in accordance with this Tanzania Standard, if the 
final value observed or calculated is to be rounded off, it shall be done in accordance with TZS 4.  
1 Scope  
 
This Tanzania Standard specifies requirements , methods of sampling and test ing for raw walnut  
kernels obtained from walnut  tree (Juglans regia L .) intended  for human consumption  or to be used 
in the food industry.  
 
2 Normative  references  
 
The following documents are referred to in the text in such a way that some or all of their conte nt 
constitutes requirements 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 ;  
 
Codex Stan 193, General Standard for Contaminant s and Toxins in Food and Feed  
 
TZS 4, Rounding off numerical values  
TZS 109, Food  processing units – Code of hygiene – General  
TZS 122,  Microbiology of food and feeding Stuffs  – Horizont al method for the detection of S almonella 
spp 
 
TZS 538, Packaging and labeling of foods  
TZS 731,  Microbiology of food and feeding Stuffs -Horizon tal method for the detection and 
enumeration of presumptive Escherichia Coli –  Most Probable Number Technique  
TZS 742, O leaginous seeds – Sampling   
TZS 799 ,  Foodstuffs – Determinat ion of aflatoxin B1, and the total content of aflatoxins  B1, B2, G1 
and G2 in cereals, nuts and derived products – High-performance liquid chromatographic method  
TZS 1314  – 1, Oilseeds  – Determination of content of impurities  
TZS 1314  – 2, Oilseeds  – Deter mination of moisture and volatile matter content  
TZS 1314  – 4, Oilseeds  – Determ ination of acidity of oils  
  
                                                                                                             AFDC 19  (1127) DTZS  
 TZS 2426  - 2, Microbiology of food and animal feeding stuffs - Horizontal method for the enumeration 
of yeasts and moulds - Part 2: Colony count tec hnique in products with water activity less than or 
equal to 0.95  
 
3 Terms and d efinitions   
 
For the purposes of this Tanzania Standard, the following terms and definitions  shall apply:  
  
3.1 walnut  
edible nuts obtained from varieties of the species Juglan s regia L  
 
3.2 raw walnut  kernels  
product obtained by deshelling nuts of varieties (cultivars) grown from Juglans regia L. and which 
have not been subjected to roasting and/or various forms of chemical treatment . 
 
3.3 foreign matters  
any organic or inorgan ic matter other than raw walnut  kernels.  
 
3.4 damaged kernels  
walnut kernel which are  damaged mechanically, or by mould or weevils, or those showing internal 
discoloration of kernels material ly affecting the ir quality.  
 
4. Requirements  
 
4.1 General require ments  
 
4.1.1  Raw walnut s kernels  shall be sound, clean, matured   and dry.  
 
4.1.2  Raw walnut kernels shall be free from rancidity, mould, foreign smell and/or taste, living insects 
and mites.  
  
4.1.3  Raw walnut kernels shall be free from dead insects, rod ent contamination, insect fragments and 
damage caused by insect pests visible to the naked eye . 
 
4.2 Specific requirements  
Raw walnut  kernels  shall comply with specific requirements given in Table 1 when tested in 
accordance with the methods specified ther ein; 
                        
Table 1- Specific requirements for raw walnut  kernels  
 
S/N 
 Characteristic  Requirement  Test method s 
i) Moisture content,% (m/m) max.  5 
 TZS 1314  – 2  
ii) Free fatty acids  as oleic %, m/m,  
max. 1.25 TZS 1314  – 4  
iii) Damaged  kernels  % by mass, max . 2 
 TZS 1314 – 1 
iv) Foreign matters , % by mass, max.  0.1 
 TZS 1314  – 1  
 
 
 
 
5. Contaminants  
  
                                                                                                             AFDC 19  (1127) DTZS  
 5.1 Heavy Metal contaminats  
Raw walnut  kernels  shall comply with those maximum metal contaminants st ipulated in CODEX STAN 
193. 
 
5.2 Pes ticide residues  
Raw walnut  kernels  shall comply with those maximum residue limits established by th e Codex 
Alimentarius Commission.  
 
5.3 Mycotoxin  
 
Raw walnut kernels  shall conform to those maximum mycotoxin limits established by the Codex 
alimentarius Co mmission.   
 
5.3.1 Aflatoxin  
 
In particular aflatoxin level for raw walnut kernels shall not exceed ma ximum limits as given in Table 2  
when tested in accordance with test method specified therein:  
 
 
                         Table 2 - Aflatoxin  limits for raw walnut  kernels  
S/N Aflatoxin  Maximum limit  (µg/kg ) Method of test  
i) Total aflatoxin  10  TZS 799  
 ii) aflatoxin B1  5  
 
6 Hygiene  
6.1 Raw walnut  kernels  shall be processed, handled and stored in accordance with TZS 109.  
 
6.2 Raw walnut  kernels  shall c omply with microbiological limits specified in Table 3 when tested in 
accordance wit h the methods specified therein;  
 
Table 3 - Microbiological limits for raw walnut  kernels  
 
S/No  Microorganism   limit Method of test  
 
i) Yeast and Moulds cfu/g,max  103 TZS 2426  - 2 
ii) Escherichia coli , MPN /g   absent  TZS 731  
iii) Salmonella per 25  g absent  TZS 122  
 
7 Sampling and methods of test  
7.1 Sampling  
 
Sampling of raw walnut  kernels  shall be done in accordance with TZS 742.  
 
7.2 Methods of test  
 
Raw walnut  kernels shall be tested in accordance with the methods specified  in table 1,2 and 3 in this 
standard.  
 
 
  
                                                                                                             AFDC 19  (1127) DTZS  
 8 Packing, Marking a nd Labeling  
8.1 Packing   
 
Raw walnut  kernels  shall be packed in suitable and hygienic food grade packaging materials which 
ensure that  the saf ety and quality requirements specified in this standard are maintained throughout 
the shelf life of the product.  
 
8.2 Marking and labeling  
 
8.2.1 The product shall be marked and labeled in accordance with TZS 538 . In addition each 
container/packet of product shall be legibly and indelibly marked with the following information :  
 
a) Name of the product  as ‘R aw walnut  kernels”  
b) Trade name or brand, if any;  
c) Name, address of the processor and/or packer;  
d) Batch  or lot number;  
e) Date of packing;  
f) Expiry date;  
g) Net weight  in metric unit ; 
h) Country of origin;  
i) Storage condition s 
j) Instruction on d isposal of used packages  
 
8.2.2  Language on the label shall be in Kiswahili or Kiswahili and English. A second language may 
be used depe nding on the designated market  
 
8.2.3  The containers shall also be marked with TBS Standards Mark of Quality.  
 
NOTE - The TBS Standards Mark of Quality shall be used by the manufacturers only under license from TBS. 
Particulars of conditions under which the licenses are granted, shall be obtain ed from TBS.