  AFDC 27 (552) DTZS  
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                DRAFT TANZANIA STANDARD  
 
 
 
General S tandard for food safety   
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
TANZANIA BUREAU OF STANDARDS  
   
 
 
 
  
 
 
 
 
 
 
 
 
   AFDC 27 (552) DTZS  
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0 Foreword  
Supply of safe food  contributes to protection and promotion of health of consumer. It als o support s national 
economies, trade and tourism, and contribute s to food and nutrition security  for sustainable development.  
Unsafe  food poses  consumer  health threats  and may create a vicious cycle of diarrhoea and malnutrition . It 
also may adversely affe ct nutritional status of the most vulnerable groups  such as infants, young children, 
pregnant women, elderly and the immuno -compromised  consumers . In view of this, control  and monitoring of 
physical, chemical and microbiological  food safety hazards  across the food value chain is of the utmost 
importance .  
This Tanzania S tandard has been prepared  as a generic  standard  to address  requirements  of food additives, 
chemical and microbiological contaminants in food products to help stakeholders (food industry, Government  
and consumers) along the food supply chain to make proper decision for the purpose of ensuring consumers ’ 
health  and fair trade . It is therefore expected that th is generic standard among other things will help food law 
enforcers to make decision s on the safety of all food products . 
In the preparation of this Tanzania Standard , profound assistance was drawn from Tanzania National 
Standards , East African Community Standards , Codex  General S tandards for C ontaminants and Toxins in food 
and feed (Codex S tan 193 -1995), China’s National Food Safety Standard for Maximum Levels of Mycotoxin in 
Foods (GB 2761 -2012), Chin a’s National Food Safety Standard for Maximum Levels of Contaminants  (Metal 
contaminants)  in Foods, (GB 2762 -2012), Chin a’s National Food safety Standard of Pathogen Limits for Food 
(2014) , and Indian food  Safety Standards (Contaminants, Toxins and Residues) Regulations , EC No 
1441/2007 - amending Regulation (EC) No 2073/2005 on microbiological criteria for foodstuffs and The 
Prevention of Food A dulteration Rules, 1955, I ndia. 
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 round ed off, it shall be done in accordance with TZS 4 : (See clause 2) .  
 
 
 
 
 
 
 
 
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 1 Scope  
This Tanzania  Standard specifies permissible  limits  for food additives , toxins, and contaminants  including 
heavy metals , pathogenic  microorganisms, pesticide residues, and veterinary  drug residues in food s. This 
general standard applies  to   all foods intended for direct human consumption and further processing in 
particular where there is no a specific product standard  or the  specific product standard  doesn’t specify the 
limits.  
  
2 Normative  references  
 
The following referenced documents are in dispensable for the application 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.  
 
TZS 4, Rounding off of Numerical Values  
    
Codex Pesticides Residues in Food Online Database  
 
CXM 2 , Maximum Residue Limits (MRLs) and Risk Management Recommendations (RMRs) for Residues of 
Veterinary Drugs in Foods  
 
CXS 192  -1995 , General Standard for Food additives  
 
TZS 538 - Packaging and l abelling of foods  
 
TZS 109 , Code of hygiene for food processing unit — General  
 
TZS 472, Cassava and cassava products — Determination of total cyanogen’s — Enzymatic assay method  
ISO 2590  - General method for the determination of arsenic - Silver diethyldithioca rbamate photometric 
method  
TZS 1335/ ISO 8294 , Animal and vegetable fats and oils - Determination of copper, iron and nickel contents - 
Graphite furnace atomic absorption method  
TZS 799/ISO 16050 ,  Foodstuffs  - Determination of aflatoxin B1 and the total cont ent of aflatoxins B 1, B2, G 1 
and G 2 in cereals, nuts and derived products - High-performance liquid chromatographic method   
ISO 14501 - Milk   and   milk   powder - Determination of aflatoxin M 1 content, Clean -up by immunoaffinity 
chromatography  and determina tion   by   high -performance   liquid   chromatography  
TBS/AFDC 27 (6732)  Foodstuffs - Determination of fumonisin B 1 and B 2 in maize based foods - HPLC 
method with immunoaffinity column clean -up and fluorescence detection  
TBS/AFDC 27 (6733)  Foodstuffs - Determination of fumonisin B 1 and fumonisin B 2 in processed maize - 
containing foods for infants and young children - HPLC method with immunoaffinity column clean -up and 
fluorescence detection after pre -column derivatisation  
 
TZS 2648 /ISO 8128 -1- Apple juice , apple juice concentrates and drinks containing apple juice. De termination 
of Patulin content, Part 1: Method using high -performance liquid chromatography  
 
TBS/AFDC 27 (6738)  Foodstuffs - Determination of patulin in fruit juice and fruit -based puree for i nfants and 
young children - HPLC method with liquid/liquid partition clean  up and solid phase extraction and UV detection    AFDC 27 (552) DTZS  
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TZS 2615  Foodstuffs - Determination of ochratoxin A - HPLC method with immunoaffinity column clean  up and 
fluorescence detection  
 
TZS 118/ ISO 4833 -1, Microbiology of the food chain - Horizontal method for the enumeration of 
microorganisms - Part 1: Colony count at 30 degrees C by the pour plate technique  
TZS119/ISO 4831, Microbiology of food and animal feeding stuffs - Horizontal method for the detection and 
enumeration of coliforms - Most probable number technique  
TZS 2426 -1: 2019/ISO 21527 -1, Microbiology of food and animal feeding stuffs  - Horizontal method for the 
enumeration of yeasts and moulds - Part 1: Colony count technique in pr oducts with water activity greater 
than 0.95  
TZS 2426 -2: 2019/ISO 21527 -2, Microbiology of food and animal feeding stuffs - Horizontal method for the 
enumeration of yeasts and moulds - Part 2: Colony count technique in products with water activity less tha n 
or equal to 0.95  
TZS 122 / ISO 6579 -1, Microbiology of the food chain - Horizontal method for the detection, enumeration and 
serotyping of Salmonella - Part 1: Detection of Salmonella spp.  
TZS 852 - 1/ISO 11290 -1, Microbiology of the food chain - Horizo ntal method for the detection and 
enumeration of Listeria monocytogenes and of Listeria spp. - Part 1: Detection method  
TZS 125 /6888 -1, Microbiology of food and animal feeding stuffs - Horizontal method for the enumeration of 
coagulase -positive staphylococ ci (Staphylococcus aureus and other species) - Part 1: Technique using 
Baird-Parker agar medium  
TZS 730/ ISO 16649 -1, Microbiology of the food chain - Horizontal method for the enumeration of beta -
glucuronidase -positive Escherichia coli -- Part 1: Colony -count technique at 44 degrees C using membranes 
and 5 -bromo -4-chloro -3-indolyl beta -D-glucuronide  
TZS 2279 /ISO 10272 -1, Microbiology of the food chain  - Horizontal method for detection and enumeration of 
Campylobacter spp.- Part 1: Detection method  
TZS 127/ISO 21872 -1, Microbiology of the food chain  - Horizontal method for the determination of Vibrio spp. 
- Part 1: Detection of potentially enteropathogenic Vibrio parahaemolyticus, Vibrio cholerae and Vibrio 
vulnificus  
TZS 403: 2019 /ISO 21567 , Microbiology o f food and animal feeding stuffs - Horizontal method for the 
detection of Shigella spp. 
TZS 2427: 2019 /ISO 21871 , Microbiology of food and animal feeding stuffs - Horizontal method for the 
determination of low numbers of presumptive Bacillus cereus - Most probable number technique and 
detection method  
TZS 2422: 2019 /ISO 22964 , Microbiology of the food chain - Horizontal method f or the detection of 
Cronobacter spp. 
 
 
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 3. Terms and definitions  
For the purposes of this document, the following terms and defini tions shall apply . 
3.1 contaminant   
any substance not intentionally added to food, which is present in such food as  a result of the production 
(including operations carried out in crop and animal husbandry and veterinary drugs ), manufacture, 
processing, p reparation, treatment, packing, packaging, transport or holding of such food  or as a result of 
environmental contamination. The term does not include insect fragments, rodent hairs and other extraneous 
matter  
 
3.2 extraneous matter  
any foreign substances in f oods that are associated with objectionable conditions or practices in production, 
storage, or distribution of foods  
 
3.3 edible part  
part of food material fit  for human consumption , which remain s after manual or mechanical process  to 
remove the non -edible pa rts such as grain husk, fruit peeling, nut shell, bones in meat/fish, shell of shellfish    
 
3.4 limit  
maximum amount of a contaminant or  additive in  food and/or the edible part of the finished food products  
 
3.5 heavy metal  
any metallic chemical element that has a relatively high density and is toxic at  low concentrations, e.g., 
mercury, lead, arsenic, and cadmium  
 
3.6 toxins  
naturally occurring toxicants including toxic metabolites of toxigenic fungi that are not intentionally added to 
food  
3.7 mycotoxi n   
toxic secondary metabolite produced by toxigenic  fungi    
 
3.8 pesticide residues  
refer to the pesticides   or their metabolites that  remain on or in food after they are applied to  crops before 
and/ or after harvest or get into the food due to environmental sources  
 
3.9 veterinary drug residues  
refer to the remains of veterinary drugs or their metabolites in animal food products  
 
3.10 food additive  
food additive means any substance not normally consumed as a food by itself and not normally used as a 
typical ingredient of the food, whether or not it has nutritive value, the intentional addition of which  to food for 
a technological (including organoleptic) purpose in the manufacture, p rocessing,  preparation, treatment, 
packing, packaging, transport or holding of such food results, or may be  reasonably expected to result   AFDC 27 (552) DTZS  
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 (directly or indirectly), in it or its by -products becoming a component of  or otherwise affecting the 
characteristics of such foods. The term does not include contaminants or  substances added to food for 
maintaining or improving nutr itional qualities  
 
3.11 foodborne pathogens  
mainly bacteria, viruses, fungi or even parasites that are present in the food and are the cause  of major 
diseases such as food poisoning  
 
3.12 packaging material  
substance used to hold a product securely to prevent leakage and breakage  and protect  it from different 
hazard s such as germs, heat, moisture loss or moisture pick up 
 
 
 
4. Requirements  
4.1 Ge neral requirements  
4.1.1  Food product intended  for human consumption  shall not exceed the set permissible limits of additives,  
toxins, and contaminants as per this standard . 
4.1.2 Levels of toxins and contaminants in food  product  shall be determined based on the edible part of the 
food unless otherwise specified.  
4.1.3 When a permissible  limit is applied to a certain food category  all types of food  product  in that category  
are subject to the limit unless otherwise specified.   
4.1.4 When codex maximum leve ls are referred, the current version shall apply.  
  
4.2 Specific requirements  
4.2.1 Contaminants  
Contaminants in this  standard include heavy metals and residues of pesticide and veterinary drug s   
4.2.1 .1 Heavy m etal contaminants  
Food product  intended for human consumption shall  not contain heavy metals  (i.e. l ead, mercury, cadmium, 
arsenic, nickel , and tin)  in amount s that pose risks  to human health  and shall comply with the limit s as 
specified in the following tables : 
 
4.2.1.1 .1 Lead (Pb) 
 Limits of Lead in food  product  shall be as specified in Table 1.   
 
  
 
 
 
 
 
 
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 Table 1: Limits of Lead in food  product s in mg/kg unless specified  
Food Category (name)  Maximum Limit Lead 
(Pb) mg/kg  
1. Cereal s and cereal products excluding starches and baked products  0.2 
2. Roots, tubers and their products (excluding    starches  and baked products ) 0.1 
3. Banana and its products  (including rip e banana ) 0.1 
4. Vegetable and vegetable products (excluding beverages)  
Fresh vegetables, and canned vegetables (excluding, leafy v egetables, 
leguminous vegetables, tuberous vegetables , fruiting vegetables )   
Leafy vegetables  
Leguminous vegetables, tuberous vegetables  
Vegetable products (excluding canned vegetables)  
Fruiting vegetables   
0.1 
0.3 
0.2 
1.0 
0.05 
5. Fruits and Fruits pro ducts (excluding beverages)  
Fresh fruit s (excluding berries and other small fruits)   
Berries and other small fruits  
Fruit products (excluding juice and concentrates), canned strawberries and 
raspberries  
Canned fruits                         
                       0.1 
0.2 
1.0 
 
0.1 
6. Edible fungi and their products   0.3 
7. Pulses and their products  
Pulses  
Pulses products (excluding soy milk)    0.2 
0.5 
8. Nuts, oil seeds and their products    0.1 
9. Meat and meat products (including game meat)  
Meats (exc luding viscera of livestock)   
Viscera of livestock   
Meat products   
0.1 
0.2 
0.1 
10. Edible insects  0.2  
11. Aquatic animals and their products  
Fresh, frozen and smoked aquatic animals (excluding, crustaceans, bivalves, and 
Cephalopods )  
Crustacean  
Bivalves  
Cephalopods   
Aquatic products (excluding jellyfish products)   
Jellyfish products   
 
0.3 
0.5 
1.5 
1.0 
1.0 
2.0 
 
12. Dairy and dairy products  0.02 
13. Food intended for special dietary uses         
Infants formula, formula for special medical purpose  intended for infants  
Follow -up formula   
Complementary foods for infants and young children  
Sports nutritional foods  
Formulas for special medical purposes (excluding varieties related to formulas for 
special medical purposes intended for infants)   
0.01 
0.01 
0.2 
0.5 
                      0.5 (in solid 
product basis)  
14. Egg and egg products     0.1 
15. Edible fats and oils               
Vegetable f ats and oils  (excluding animal fats)  
Spreads    
Animals’  fats   
0.08 
0.04 
0.1   AFDC 27 (552) DTZS  
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 16. Condiment s, spices and herb s  0.3 
 
17. Starch and its products          0.2 
18. Baked products and confectioneries  0.5 
19. Non-alcoholic beverages  0.03 mg/L  
20. Alcoholic beverages     0.2 mg/L  
21. Tea, coffee, cocoa, and  their substitutes  (e.g. Ice tea, ice coffee, etc.  
Tea 
Cocoa 
Coffee   
1.0 
1.0 
0.1 
22. Bee products                                                               0.1 
23. Edible ices  0.01 
24 Sugar and its products  0.5 
Testing method:   See Annex A  
 
 
 
4.2.1. 1.2 Cadmium (Cd) 
 
 Limits of cadmium in food  products  shall be as  specified  in Table  2.  
                           
           Table 2: Cadmium limits in foods in mg/kg unless  specified  
Food category (name)  Maximum Limit (in Cd basis) 
mg/kg  
1. Cereals and cereal products  
Cereals and cereal products (excluding  rice) 
Rice  
0.1 
0.4 
2. Roots, tubers and their pr oducts (excluding starches  and baked products  0.1 
3. Banana and its products excluding ripe banana  NA 
4. Vegetable and vegetable products (excluding beverages)  
Fresh vegetables (excluding leafy vegetable s, leguminous vegetables, root and 
tuberous vegetables, stem vegetables , fruiting vegetable )   
Leafy vegetables and celery  
Leguminous vegetables, root, stem vegetables (excluding celery)   
Fruiting vegetable  and tuberous vegetables  0.05 
 
0.2 
0.1 
0.2 
0.05 
5. Fruit and fruit products excluding beverages  0.05 
6. Edible fungi and its products  
Fresh edible fungi   
Edible fungi products   
0.2 
0.5 
7. Pulses and their products  
Pulses excluding soybeans  
Soybeans   
0.1 
0.2 
8. Nuts, oil seeds, and their products ex cluding peanut  
Peanut  0.1 
0.5 
9. Meat and meat products  including game meat  
Meats (excluding viscera of livestock and poultry)   
Liver of the livestock and poultry  
Kidney of the livestock and poultry  
Meat products (excluding liver, kidney , and dried pr oducts )   
Liver products  
Kidney products  
Dried meat products   
0.1 
0.5 
1.0 
0.1 
0.5 
1.0 
0.05   AFDC 27 (552) DTZS  
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10. Edible insects  0.03 
11. Aquatic animals and their products   
Fresh, frozen and smoked aquatic animals (excluding, crustacean, bivalves, 
molluscs, and cepha lopods)   
Crustacean s      
Bivalves, molluscs, and cephalopods    
0.3 
 
0.5 
2 
12. Dairy and dai ry products  NA 
13. Food intended for special dietary uses  
 
Powdered formula manufactured from cow’s milk proteins or protein hydrolyses  
 
Liquid formula manufact ured from cow’s milk proteins or protein hydrolyses  
 
Powdered formula manufactured from soya protein isolates alone or in mixture with 
cow’s protein  
 
Liquid formula manufactured from soya protein isolates alone or in mixture with 
cow’s protein  
 
Processed cereal -based foods for infants and young children   
0.01 
 
0.005  
 
 
0.02 
 
 
0.01 
0.04 
14. Egg and egg products  0.05 
15. Edible fats and oils   0.1 
16. Spices, condiments, and herbs  NA 
17. Starch and its products  0.1 
18. Baked products and confectioneries  0.1 
19. Non-alcoholic beverages  NA 
20. Alcoholic beverages  NA 
21. Tea, coffee, cocoa and their substitute e.g. ice tea, ice coffee, etc.  
Tea 
Products with more than 70% cocoa  
Products with 50% -70% cocoa   
0.1 
0.9 
0.8 
22. Bee products  0.01 
23. Edible ice  0.03 
24. Sugar and its products  NA 
 
Testing method : See Annex B  
  
 
 
 
 
 
 
 
 
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4.2.1.1.3 Mercury  (Hg)  
 Limits of mercury in  food products  shall be as specified in Table  3.  
 
 
Table 3: Limits of m ercury   in food  products  in mg/kg unless 
otherwise specified  
 
Testin g method : see Annex C  
  
 
 
 
 Food Category (name)  Maximum Limit (in Hg basis) 
mg/kg  
Total mercury  Methyl mercury   
1. Cereals and cereal products excluding starch es and baked 
products  NA  
2. Roots, tubers and their pr oducts (excluding starches  and baked 
products  NA  
3. Banana and its  products               NA  
5. Fruit and fruit products  (excluding beverages)  NA  
6. Edible fungi and its products   0.01 — 
7. Pulses and their products  NA  
8. Nuts, oil seeds, and their products  NA  
9. Meat and meat products  (including  game meat ) 0.01  
10. Edible insects  NA  
11. Aquatic animals and their products  
Fish and their products (excluding carnivorous fishes and their 
products)   
Carnivorous fishes and their products  — 
 
— 0.5 
 
1.5 
12. Dairy and dai ry products  NA  
13. Food intended for infa nts, young children and special dietary 
uses  NA  
14. Egg and egg products  NA  
15. Edible fats and oils  NA  
16. Spices, condiments  and herbs  0.1  
17.  Starch and its  products  NA  
18.  Baked products and confection eries NA  
19. Non-alcoholic beverages  NA  
20.  Alcoholic beverages  NA  
21. Tea, coffee, cocoa and their substitutes  e.g. ice tea, ice coffee,  NA  
22.  Bee products                                         0.03  
23. Edible ices  0.001   
24. Sugar and its products  NA  
NOTE For aquatic animal a nd its products, total mercury could be tested first; if the total mercury level 
is lower than the limit of methyl mercury, it is not necessary to test the methyl mercury; otherwise, the 
methyl mercury shall be tested.                                AFDC 27 (552) DTZS  
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4.2.1.1.4 Arsenic (As) 
Limits of arsenic limits in food  products  shall be as  specified  in Table 4  
 
Table 4: Limits of  arsenic in food  products  in mg/kg unless  
specified          
 
Testing method :  ISO 2590  
  
 
 Food Category  (name)  Maximum Limit (in As basis) 
mg/kg  
Total arsenic  Inorganic arsenic  
1. Cereal s and cereal products (particularly rice)  
Paddy  
Rice    
0.35 
0.2  
— 
— 
1. Roots, tubers and their products (excluding  baked products ) NA  
2. Banana and its products  0.2  
4. Vegetables and their products (ex cluding beverages)  
Fresh vegetable and vegetable   products  0.5 
 — 
5. Fruits and fruit products (excluding beverages)  
Fresh fruit pulp  
Fruit juices  
Dried fruits   
0.1 
0.2 
0.2  
6. Edible fungi and their products  0.2  
7. Pulses and their products  NA  
8. Nuts, oil seeds , and their products  0.1  
9. Meat and meat products (including game meat)   0.1 — 
10. Edible insects  NA  
11. Aquatic animals and their products       0.1  
12. Dairy and dairy products  
Raw milk, heat treated milk, fermented  milk  
Whole and  skimmed milk powder   
0.1 
0.5 — 
— 
13. Food intended for special dietary uses  
Processed cereal -based foods for infants and young children  0.1  
14. Eggs and eggs products  NA  
15. Edible fats and oils  0.1 — 
16. Spices, condiments and herbs  0.2  
17.  Baked produc ts and confection eries 1  
18. Non-alcoholic beverages  NA  
19. Alcoholic beverages  NA  
20.  Tea, coffee, cocoa and their products and substitutes  
Tea 
Cocoa  
Coffee   
0.15 
1.0 
0.5  
— 
21. Bee products  0.1  
22. Edible ices  0.01  
23. Sugar and its products  1     AFDC 27 (552) DTZS  
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 4.2.1.1.5 Tin (Sn) 
 
Test method :  see Annex D  
 
 
4.2.1.1.6 Nickel (Ni) 
Limit s of nickel in food  products  shall be as  specified  in Table 6.   
 
    Table 6: Limits of nickel in  food  products  in mg/kg unless 
specified  
 
 
  
4.2.2 Toxins  
The toxins, which are covered by this standard,  includ e cyanogenic glycosides and natural toxins produced by 
living organisms such as mycotoxins.  
 
4.2.2.1  
Mycotoxins  
The mycotoxin s covered by this  standard  includ e aflatoxins ( aflatoxin B 1, aflatoxin total (B 1+ B 2+ G 1+G 2) and  
aflatoxin  M1), fumonisins  (B1, B2 alone or in combination) , patulin,  and ochratoxin A  
 
4.2.2.1 .1 Aflatoxin   
Limits of aflatoxin in food  product  shall be as specified  in Table 7. 
     
 
Table 7: Limits of Aflatoxins B 1, Total Aflatoxins and Aflatoxin M 1 in foods  Limits of t in in food  products  shall be as  specified  in Table 5. 
 
 
Table 5: Limits of t in in food  products  in mg/kg unless specified  
Food Category (name)   Maximum 
Limit ( in Sn 
basis) mg/kg   
Foods in tin -plated containers (excluding beverages, formula for infants and young 
children, complementary foods for infants and young children)   250 
Canned beverages, including fruit juices and vegetable juices  
Canned infants and follow -up formula, a nd complementary foods for infants and young 
children  
Canned dietary foods for special medical purposes  
Food products including canned foods in non -tin-plated containers  150 
5 
 
5 
50 
Bee products  5 
Food Category (name)    Maximum Limit 
(in Ni basis) 
mg/kg  Test 
method  
Fats and their products  
Products mainly produ ced of hydrogenated 
vegetable oil   
0.1  
TZS 1335/ ISO 8294    AFDC 27 (552) DTZS  
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Test method: For aflatoxin B 1 and aflatoxin total, TZS 799/ ISO 16050 ; for aflatoxin  M1, ISO 14501  
 
 
     
 
Food Category (name)  
 Maximum Limit (μg /kg)    
Aflatoxin B 1 Total Aflatoxin 
(B1+B2+G 1+G 2)  Aflatoxin M 1 
Cereal s and cereal products  including  starch and baked 
products  
Cereals and all products derived from cereals, including processed 
cereal products, with the exception of processed cereal -based 
foods and baby foods for infants and young children, dietary foods 
for special medical purposes intended specifically for infants  
Cereal -based breakfast and cereal -based snacks   
5 
 
 
 
  
10 
 
 
 - 
Dietary foods intended for infants and young children  
Processed cereal -based foods and baby foods for  
infants and young children  
Infant formulae and follow -on formulae, including  
infant milk and follow -on milk 
Dietary foods for special medical purposes intended specifically for 
infants   
0.5 
 
        - 
 
0.5  
- 
 
 -                  
 
                -  
- 
 
0.25 
Nuts, oil seeds, and their products  5 10  
Roots, tubers,  and their products  
Dried roots and tubers (e.g . cassava, potatoes, and yams) and 
processed products thereof, intended for human cons umption or 
use as an ingredient in foodstuffs   
5  
10  
- 
Fruits and their products  (excluding beverages ) 
Dried fruit /seed  and processed products thereof, intended  
for human consumption or use as an ingredient in foodstuffs  5 10  
 Vegetables and their prod ucts (including dried vegetable 
seeds  and excluding beverages ) 
Dried vegetables  and processed products thereof, intended  
for human consumption or use as an ingredient in foodstuffs   
5  
10  
- 
Spices   
Spices including Capsicum spp . (dried fruits thereof, wh ole or 
ground,  chillies, chilli powder, cayenne and paprika); Piper spp . 
(fruits thereof, including white and black pepper); Myristica 
fragrans  (nutmeg); Zingiber officinale  (ginger); Curcuma longa  
(turmeric), cinnamon, cardamom, clove, and their mixtures    
 
5  
 
10  
 
- 
Dairy and dai ry products  
Raw milk, powdered milk, heat -treated milk and milk for the  
manufacture of milk -based products   
-  
-  
0.5 
Starch and its  products  5 10  
Alcoholic and non - alcoholic beverages (only for cereal -based)  5 10    AFDC 27 (552) DTZS  
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 4.2.2.1.2 Fumonisin s (B1 and B 2) 
Limits of f umonisin s in food  product s shall be as specified  in Table  9.  
 
 Table 9: Limits of fumonisins  (B1, B2, alone  or in co mbination)  in food products  
Food Category (name)   maximum 
limit (μg /kg)  Test method  
Cereals and all products derived from cereals, including processed 
cereal products  and starches , with the exception of processed cereal -
based foods and baby foods for in fants and young children, dietary 
foods for special medical purposes intended specifically for infants   
2000  TBS/AFDC27 (6733) P3  
Cereal -based breakfast and cereal -based snacks  1000  
Processed cereal -based foods and baby foods for  
infants and young chil dren 200 TBS/AFDC27 (6733) P3 
Dietary foods for special medical purposes intended specifically for 
infants  200 
 
4.2.2.1.3 Ochratoxin A  
Limits of ochratoxin A in food products shall be as specified in Table 1 0. 
 
 
Table 1 0: Limits of Ochratoxin A in food products  
Food Category (name)  Maximum Limit μg /kg  Test method  
Fruits and fruit products (excluding beverages)  
Grape juice, concentrated grape juice, grape nectar  
Dried vine fruits (currants, raisin and sultanas)   
2.0 
10.0 
 TZS 2615  
Coffee and coffee p roducts (excluding soluble coffee)  
Soluble coffee (instant coffee)  5.0 
10.0  
 
 
4.2.2.1.4  Patulin  
Limits of patulin in food products shall be as specified in Table 1 1.  
 
                     Table 1 1: Limits of patulin in food products  
 
 
 
 
 
 
 
 
 
 
4.2.2.2 Hydrocyanic Acid  
Applies only to foods containing cyanogenic glycoside s as the main source of cyanide . 
 
The limits of Hy drocyanic acid in food products shall be as speci fied in Table 1 2 
        
 Food Category (name )   Maximum Limit (μg /kg)  Test method  
Fruits and their products (excluding beverages)  
Apple fruit products including liquor (with the exception of solid 
apple products)   
Solid apple products   
50 
 
25  
TZS 2648 
/ISO 8128 -1 
 
Foods for infants and young child ren 
Apple juices and apple -based  products  
  
10 TZS 2648 
/ISO 8128 -1   AFDC 27 (552) DTZS  
15 
 Table 1 2: Limit s of Hydrocyanic acid in food products  
Food Category (name)  Maximum limit mg/kg  
Cassava and its products  
Cassava and its products excluding gari  
 
Gari  10 
2 
 
Test method: TZS 472  
 
4.2.3 Other chemical contaminan ts 
 
4.2.3.1 Vinyl Chloride/ Chloride of Vinyl  
 
Limits of Vinyl Chloride in food products shall be as specified in Table  13. 
 
Table 13: Limits of Vinyl Chloride in food products in mg/kg unless specified  
 
4.2.3.2 Acrylonitrile/ vinyl cyanide (VCN)  
Limits of Acrylonitrile in food products shall be as specified in Table 1 4. 
 
Table 14: Limits of Acrylonitrile/ vinyl cya nide (VCN) in food products in mg/kg unless specified  
 
4.2.3.3 Chloropropanols  
 
The limits of Chloropropanols in food products shall be as specifi ed in Table 1 5 
 
    
 
Table 15: Limits of Chloropropanols in food products in mg/kg  
 
 
 
4.2.3.4 Melamine  
The limits of Melamine in food products shall be as specified in Table 16. 
 Food Category (n ame)  Maximum 
Limit mg/kg  
 Foods in contact with materials with migrant Vinyl Chloride such as Plastic (PVC) 
containers  0.01 
Food Category (n ame)  Maximum 
Limit mg/kg  
 Foods in contact with materials with migrant Acrylonitrile  0.02 
Food Category (n ame)  Maximum   
Limit  mg/kg  
 Liquid condiments containing acid hydrolyzed vegetable proteins  
 
NOTE: The Maximum limit does not apply to naturally fermented soy sauce.  0.4   AFDC 27 (552) DTZS  
16 
    Table 1 6: Limits of Melamine in food products  
  
  
4.2.4 Pesticide residues  
Food of plant and/or animal origin intended for human consumption shall not exceed maximum residue s limits 
of pesticide as established by Codex  Alimentarius Commission.   
 
4.2.5 Veterinary drug residues  
Food and f ood products of animal origin  intended for human consumption shall not exceed maximum residues 
limits of veterinary drugs as established by Codex  Alimentarius Commission.  
 
4.2.6 Foodborne pathogenic m icroorganisms  
Food  products covered  by this standard sh all be prepared in accordance with TZS 109  and other Codes of 
Practice recommended by the Codex Alimentarius Commission, which  are relevant to th ose products . 
  
Food and food product s intended for human consumption shall comply with the microbiological limi ts provided 
in Table 17. 
 
                               
Table 17: Microbiological limits in foods  
 
Food Category  Microorganisms  Limits  Test method  
Meat and meat products  (including game meat)  
 
Processed meat products  
 
Ready to eat raw meat product s Salmonella spp. Not detected/25g  TZS 122 / ISO 6579 -1 
Clostridium botulinum (for 
canned meat products)  Not detected/25g  TZS 121  
Clostridium perfringens  Not detected/25g  TZS/ISO 7937  
Listeria monocytogenes (for 
products that support their 
growth ) Not detected/25g  TZS 852 -1/ISO 11290 -1 
Coagulase positive  
Staphylococcus aureus  102 cfu/g  TZS 125/6888 -1 
Escherichia coli (cfu/g)  Absent  TZS 730/ ISO 16649 -1 
Poultry and poultry products with 
exception to egg and their products Campylobacter spp. Not detected/ 25g  TZS 2279:2018/ ISO 
10272 -1:2017  Food Category (n ame)  Maximum 
Limit  mg/kg  
Food with exception to  infant formulae  2.5* 
Powdere d infant formula  1 
Liquid infant formula  
 0.15 
* The M aximum limit  applies to levels of melamine resulting from its non -intentional and unavoidable 
presence in food.  
The M aximum limit  does not apply to  food for which it can be proven that the level of m elamine higher than 
2.5 mg/kg is the consequence of:  
-Authorised use of cyromazine as insecticide. The melamine level shall not exceed the level of cyromazine. 
-Migration from food contact materials . The melamine level shall not exceed the acceptable  migration  limit.    AFDC 27 (552) DTZS  
17 
 and canned poultry meat  Salmonella spp. Not detected/ 25g  TZS 122/ ISO 6579 -1 
E. coli (cfu/g)  Absent   TZS 730/ ISO 16649 -1 
Coagulase positive  
Staphylococcus aureus  102cfu /g TZS 125/ISO 6888 -1 
Clostridiu m perfringens  Not detected/ 25g  ISO 7937  
Canned poultry meat  Clostridium botulinum  Not detected/ 25g  TZS 121  
E. coli (cfu/g)  Absent  TZS 730/ ISO 16649 -1 
Salmonella spp. Not detected/25g  TZS 122 / ISO 6579 -1 
Coagulase positive  
Staphylococcus aureus   102 cfu/g  TZS 125/ISO 6888 -1 
Egg and egg products  
 Salmonella spp. Not detected/25g  TZS 122 / ISO 6579 -1 
E. coli  (cfu/g)  Absent  TZS 730/ ISO 16649 -1 
Coagulase positive  S. 
aureus  102 cfu/g  TZS 125/ISO 6888 -1 
Aquatic animals and their  products  
Processed fish products  
Ready -to-eat raw fish   
Ready -to-eat algae products  Salmonella spp. Not detected/25g  TZS 122/ISO 6579 -1 
Vibrio parahaemolyticus 
(For marine products)  Not detected/25g  TZS 127: 2018/ 
ISO/21872 -1:2017  
Vibrio cholerae (For fresh 
water products)  Not detected/25g  TZS 127: 2018/ 
ISO/21872 -1:2017  
Coagulase positive  S. 
aureus  102cfu/g  TZS 125 /ISO 6888 -1 
 
E. coli (cfu/g)  Absent  TZS 730/ ISO 16649 -1 
Shigella spp. Not detected/25g  TZS 403:2019/ISO 
21567:2004  
C. perfringens  Not dete cted/25g  TZS/ISO 7937  
Dried fish/salted fish/dried salted fish  Salmonella spp. Not detected/25g  TZS 122/ISO 6579 -1 
V. parahaemolyticus  Not detected/25g  TZS 127: 2018/ 
ISO/21872 -1:2017  
Coagulase positive  S. 
aureus  102cfu/g  TZS 125 /ISO 6888 -1 
 
Shige lla spp. Not detected/25g  TZS 403:2019/ISO 
21567:2004  
E. coli (cfu/g)  Absent  TZS 730/ ISO 16649 -1 
Vibrio cholerae (For fresh 
water products)  Not detected/25g  TZS 127: 2018/ 
ISO/21872 -1:2017  
Canned fish  Clostridium botulinum  Not detected/25g  TZS 121  
C. perfringens  Not detected/25g  TZS/ ISO 7937  
 
Cereals and cereal products excluding starches and baked products  
 
Cereals and cereal products 
excluding starch and baked products  
  
 Salmonella spp. Not detected/25g  TZS122/ISO 6579 -1 
E. coli (cfu /g)  Absent  TZS 730/ ISO 16649 -1 
Coagulase positive  S. 
aureus  102cfu/g  TZS 125 /ISO 6888 -1 
Bacillus cereus  Not detected/25g  TZS 2427:2020/ISO 
21871:2006    AFDC 27 (552) DTZS  
18 
  
Pulses and their products  
    Salmonella spp. Not detected/25g  TZS 122 /ISO 6579 -1 
E. coli  (cfu/g)  Absent  TZS 730/ISO 16649 -1 
Coagulase positive  S. 
aureus  102cfu/g  TZS.125 -1 /ISO 6888 -1 
Tea, cocoa, coffee and their substitutes    
 Salmonella spp. Not detected/25g  TZS 122/ISO 6579 -1 
E. coli  (cfu/g)  Absent  TZS 730/ISO 16649 -1 
Vegetable and vegetable  products (excluding beverages)  
Vegetables and their products 
(including preserved vegetables)  Salmonella spp. Not detected/25g  TZS 122/ISO 6579 -1 
Coagulase positive  S. 
aureus  102cfu/g  TZS 125/ISO 6888 -1 
E. coli  (cfu/g)  Absent  TZS 730/ISO 16649 -1 
Fruits and fruits products (excluding beverages)  
 Salmonella spp  Not detected/25g  TZS 122/ISO 6579 -1 
Coagulase positive  S. 
aureus  102cfu/g  TZS 125/ISO 6888 -1 
E. coli  (cfu/g)  <101 /cfu/g  TZS 730/ISO 16649 -1 
Edible fungi and their products  
 Salmonella sp p Not detected/25g  TZS 122/ISO 6579 -1 
Coagulase positive  S. 
aureus  102cfu/g  TZS 125/ISO 6888 -1 
E. coli  (cfu/g)  <101 /cfu/g  TZS 730/ISO 16649 -1 
Spices, Condiments and herb s 
Soy sauce   
Sauce and sauce products   
Aquatic dressing  
Composite seasonings  Salmonella spp. Not detected/25g  TZS 122/ISO 6579 -1 
Coagulase positive S. 
aureus  102cfu/g  TZS 125/ISO 6888 -1 
V. parahaemolyticus (only 
applies to seasonings 
containing marine 
ingredients ) Not detected /25g  TZS 127: 2018/ 
ISO/21872 -1:2017  
V. cholera e (applies 
seasoning containing fresh 
water ingredients)  Not detected/25g  TZS 127: 2018/ 
ISO/21872 -1:2017  
E. coli  (cfu/g)  Absent  TZS 730 -2:2007/16649 -1 
Spices  B. cereus  Not detected/25g  TZS 2427:2020/ISO 
21871:2006  
Coagulase positive  S. 
aureus  102cfu/g 
 TZS 125/ISO 6888 -1 
E. coli  (cfu/g)  <101  TZS 730 -2:2007/16649 -1 
Salmonella  spp.  Not detected/25g  TZS 122/ISO 6579 -1 
Nuts, oil seeds, and their products  
Nuts, oil seeds and their products  Salmonella spp. Not detected/25g  TZS 122/ISO 6579 -1 
E. co li (cfu/g)  Absent  TZS 730/ISO 16649 -1 
Coagulase positive S. 
aureus  102cfu/g  
 TZS 125/ISO 6888 -1   AFDC 27 (552) DTZS  
19 
 Foods for infants and young children and foods for special dietary needs or medical purposes  
Cereal -based formula for infants, 
young children and foods for special 
dietary needs or medical purposes  
 Salmonella spp. Not detected/25g  TZS 122/ISO 6579 -1 
E. coli (cfu /g)  Absent  TZS 730 -2:2007/16649 -1 
Coagulase positive  S. 
aureus  102cfu/g  TZS 125/ISO 6888 -1 
Bacillus cereus  Not detected/25g  TZS 2427:2020/ISO  
21871:2006  
 
Dairy -based formula for infants, 
young children and foods for special 
dietary needs or medical purposes  
 Salmonella spp. Not detected/25g  TZS 122/ISO 6579 -1 
Cronobacter spp. Not detected/25g  TZS 2422:2020/ISO 
22964  
Total coliforms  Not det ected/25g  TZS 119/ISO 4831  
E. coli  (cfu /g)  Absent  TZS 730/ ISO 16649 -1 
L. monocytogenes  Not detected / 25g  TZS 852 -1/ISO 11290 -1 
Coagulase positive S. 
aureus  102cfu/g  TZS 125/ISO 6888 -1 
Clostridium perfringens  Not detected/25g  TZS/SO 7937  
Formul a for infants, young children 
and foods for special dietary needs 
or medical purposes containing 
vegetable, nuts or legumes 
ingredients  Salmonella spp. Not detected/25g  TZS 122./ISO 6579 -1 
E. coli  (cfu/g)  Absent  TZS 730/ISO 16649 -1 
Coagulase positive  S. 
aureus  102cfu/g  TZS 125/ISO 6888 -1 
Fruit-based formula for infants, 
young children and foods for special 
dietary needs or medical purposes  Salmonella  spp. Not detected/25g  TZS 122/ISO 6579 -1 
E. coli  (cfu/g)  Absent  TZS 730/ISO 16649 -1 
Coagulase posit ive S. 
aureus  102cfu/g  TZS 125/ISO 6888 -1 
Formula for infants, young children 
and foods for special dietary needs 
or medical purposes containing fish 
ingredients  
 Salmonella  spp. Not detected/25g  TZS 122/ISO 6579 -1 
Vibrio parahaemolyticus 
(applies to pr oduct 
containing fish ingredient 
from marine water  Not detected/25g  TZS 127: 2018/ 
ISO/21872 -1:2017  
Vibrio cholerae (applies to 
product containing   fish 
ingredient from fresh water)  Not detected/25g  TZS 127: 2018/ 
ISO/21872 -1:2017  
Coagulase positive S. 
aureus  102cfu/g  TZS 125 /ISO 6888 -1 
 
Shigella spp. Not detected/25g  TZS 403:2019/ISO 
21567:2004  
E. coli (cfu/g)  Absent  TZS 730 -2:2007/16649 -1 
 
Roots, tubers and their products (excluding starches and baked products)  
 Salmonella spp. Not detected/25 g TZS122/ISO 6579 -1 
E. coli (cfu/g)  Absent   TZS 730/ ISO 16649 -1 
Yeasts/Moulds  103cfu/g. max  TZS 2426 -2:2020/ISO 
21527 -2:2008  
 
Dairy and dairy products  
Raw milk, powdered milk, heat -
treated milk and other  
milk products   Total coliforms  Not detected/ 25g TZS119/ISO 4831  
E. coli  (cfu/g)  <101cfu/g  TZS 730/ ISO 16649 -1 
L. monocytogenes  Not detected /25g  TZS 852 -1/ISO 11290 -1   AFDC 27 (552) DTZS  
20 
 Coagulase positive  S. 
aureus  102cfu/g  TZS 125 /ISO 6888 -1 
 
Salmonella spp. Not detected/25g  TZS 122/ISO 6579 -1 
Clostridiu m perfringens  Not detected/25g  TZS/SO 7937  
Edible ices  
 Salmonella spp. Not detected/25g  TZS 122/ISO 6579 -1 
E. coli  (cfu/g)  Absent  TZS 730/ISO 16649 -1 
Coagulase positive  S. 
aureus  102cfu/g  TZS 125/ISO 6888 -1 
Baked products and confectionaries  
 Salm onella spp. Not detected/25g  TZS122/ISO 6579 -1 
E. coli (cfu/g)  <101cfu /g  TZS 730/ ISO 16649 -1 
Non-alcoholic beverages  
 Salmonella spp. Not detected/25g  TZS 122./ISO 6579 -1 
E. coli  (cfu/g)  Absent  TZS 730/ISO 16649 -1 
Coagulase positive  S. 
aureus  102cfu/g  TZS 125/ISO 6888 -1 
Alcoholic beverages  
 Total coliforms  Not detected/25g  TZS119/ISO 4831  
   
Bee products  
 Total coliforms  Not detected/25g  TZS119/ISO 4831  
Salmonella spp. Not detected/25g  TZS 122./ISO 6579 -1 
E. coli  Absent  TZS 730/ISO 1664 9-1 
Coagulase positive  S. 
aureus  102cfu/g  TZS 125/ISO 6888 -1 
Sugar and its products  
 Salmonella spp. Not detected/25g  TZS 122/ISO 6579 -1 
E. coli  Absent  TZS 730/ ISO 16649 -1 
Banana and its products (excluding ripe banana)  
 Salmonella spp. Not detect ed/25g  TZS 122/ISO 6579 -1 
Coagulase positive  S. 
aureus  102cfu/g  TZS 125 /ISO 6888 -1 
 
E. coli  (cfu/g)  Absent  TZS 730/ ISO 16649 -1 
Bacillus cereus  Not detected/25g  TZS 2427:2020/ISO 
21871:2006  
Edible insects  
  Salmonella spp. Not detected/25g  TZS 122 /ISO 6579 -1 
Coagulase positive  S. 
aureus  102cfu/g  TZS 125 /ISO 6888 -1 
 
E. coli  (cfu/g)  Absent  TZS 730/ ISO 16649 -1 
Starch and its products  
 Salmonella spp. Not detected/25g  TZS122/ISO 6579 -1 
E. coli  Absent   TZS 730/ ISO 16649 -1 
Coagulase positiv e S. 
aureus  102cfu/g  TZS 125 /ISO 6888 -1 
Bacillus cereus  Not detected/25g  TZS 2427:2020/ISO   AFDC 27 (552) DTZS  
21 
 21871:2006  
 
 
5 Food Additives  
The use of food additive(s) in all food products intended for human consumption shall be in conformance with 
Codex Stan 192.  The f ood additives shall be used singly from each functional class or category of additives in 
order to serve a similar technological application; unless it is technologically justified to apply as such in 
combination and proven through risk assessment that suc h application shall not end up into creating something 
else chemically that could become a health hazard to the consumer.  
 
 
6 Packaging  and Labelling  
Packaging and labelling  of foods intended for human consumption shall be in accordance with TZS 538 .   AFDC 27 (552) DTZS  
22 
 ANNE X A (Normative)  
DETERMINATION OF LEAD IN FOOD BY ATOMIC ABSORPTION 
SPECTROPHOTOMETRIC (AAS) METHOD  
A. Principle  
Organic matter is digested and Lead ( Pb) released co -precipitates with Strontium sulphate ( SrSO 4). 
Soluble sulphate salts are decanted, and prec ipitate is converted to carbonate salt, dissolve d in acid, and 
determined by AA  at 217.0 or 283.3nm.  
 
B. Apparatus  
(a) Atomic absorption spectrophotometer - Operated at 217.0  nm or 283. 3nm 
(b) Stirring motor . - With eccentric coupling for stirring centrifug e tubes.  
 
C. Reagents  
(Age all new glassware and all glassware which has contained high Pb concentration in boiling HNO 3 
before washing. Never let used glassware dry before washing, and always include final HNO 3, rinse 
followed by deionized H 2O rinse ). 
 
(a) Strontium solution.  – 2 %. Dissolve 6  g SrCl 2.6H 2O in 100 ml  H2O. 
 
(b) Ternary acid mixture . - Add 20 ml  H2O4 to 100 ml  H2O, mix, add 100 ml  HNO 3 and 40 ml  70% 
HCLO 3, and mix.  
 
(c) Nitric acid  1M. – Add 128 ml  redistilled HNO 3 to 500 - 800 ml  distilled o r deionized H 2O and dilute 
to 2L . Redistilled HNO 3 may be diluted and used without re -distllation.  
 
(d) Lead standard solutions . - (1) Stock solution . – 1000 µg/ml. Dissolve 1.5985 g Pb (NO 3)2, 
recrystallized, in ca 500 ml  1M HNO 3 in 1L volumetric flask and  dilute to volume with 1M HNO 3. (2) 
Working solutions. - Prepare 100 µg Pb/ml by diluting 10 ml stock solution to 100 ml  with 1M HNO 3. Dilute 
1, 3, 5, 10, 15, and 25 µg Pb/ml , respectively).  
 
D. Separation of Lead  
Accurately weigh test portion containing ≤ 10 g dry matter and ≥3 µg Pb. Place in 500 ml boiling Kjeldahl 
flask and add 1 ml 2 % Sr solution, C (a) , and several glass beads. Prepare a reagent blank and carry 
through same operations as test portion. Add 15 ml ternary acid mixture, C (b) , for each g dry matter and 
let stand ≥ 2  h. Heat under hood or H 2O vacuum manifold system until flask contains only H 2O4 and 
inorganic salts. ( Note:  Take care to avoid material loss from foaming when heat is first applied, and when 
foaming occurs soon after material c hars. Remove heat and swirl flask before continuing digestion. Add 
HNO 3, if necessary) . 
   AFDC 27 (552) DTZS  
23 
 Cool digest few min. (Digest should be cool enough to add ca 15 ml H 2O safely, but hot enough to boil 
when H 2O is added).  Wash while still hot 40 – 50 ml tapered -bottom centrifuge tube and swirl. Let cool, 
centrifuge 10 min at 350 × ɡ, and decant liquid into waste beaker. (Film -like precipitate on surface may be 
discarded).  Dislodge precipitate by vigorously stirring with eccentric -coupled stirring motor. To compare 
transfer, add 20 ml H 2O and 1ml 0.5M H 2SO 4 to original flask and hea t. Do not omit this step even though 
it appears transfer was complete in first wash. Wash hot contents of original digestion flask into centrifuge 
tube containing precipitate. Swirl to mix, cool, centrifuge, and decant liquid into waste beaker.  
Dislodge pr ecipitate by stirring vigorously, add 25 ml saturated (NH 4)2CO 3 solution (ca 20%), and stir until 
all precipitate is dispersed. Let stand 1 h, centrifuge, and decant liquid into waste beaker.  
After decanting, invert centrifuge tube on paper towel and drain  all liquid. Add 5 ml 1M HNO 3 (use large 
volume 1 M HNO 3 in both test solution and blank if ˃25 µg Pb is expected), stir vigorously to expel CO 2 or 
use ultrasonic bath 2 -3 min, let stand 30 min, and centrifuge if precipitate remains.  (Use same technique 
for all test solution.)  
 
E. Determination  
Set instrument to previously established optimum conditions, using air - C2H2 oxidizing flame and 217.0 or 
283.3 nm resonant wavelength. Determine A of test and blank solutions and ≥ 5 standards within 
optimum workin g range (10 – 80 %T) before and after test readings. Flush burner with 1M HNO 3 and 
check 0 point between readings. Determine Pb from standard curve of A against µg Pb/ml:  
 
          
    
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
   AFDC 27 (552) DTZS  
24 
 ANNEX B ( Normative ) 
DETERMINATION OF CADM IUM IN FOOD BY ATOMIC ABSORPTION 
SPECTROPHOTOMETRIC METHOD  
A. Principle  
Material is digested with HNO 3, H 2SO 4, and H2O2; all reactive metals are extracted from solution, after 
adjustment to ca pH 9, with dithizone - CHCl 3. Cd is removed by stripping CHCl 3 solution with dilute HCl  
and determined by AA Spectrophotometry at 228.8nm.  
 
B. Reagents and Apparatus  
(Thoroughly wash all new glassware and glassware, which  contained high Cd concentration with 8M 
HNO 3, and rinse with H 2O. Cover beakers with watch glasses during all operations.)  
 
(a) Nitric acid - Low in Pb and Cd  
 
(b) Hydrogen peroxide - 50%  
(c) Citric acid - Monohydrate, fine crystal.  
 
(d) Thymol blue indicator .  
 
(e) Dithizone solutions. - (1) concentrated solution.  - 1 mg/ml. Prepare 200 ml in CHCl 3. (2) Dilute 
solution . - 0.2 mg/ml. Dilute concentrated solution 1+ 4 with  CHCl 3. Prepare fresh daily.  
 
(f) Cadmium standard solutions . - (1) stock solution - 10mg/ml. Dissolve 1.00g Cd (Fischer Scientific 
certified 99.9% p ure or equivalent) in 165 ml HCl  in 1L volumetric flask. Dilute to volume with H 2O. (2) 
Intermediate solution.  - 10µg/ml. Dilute 10 ml stock solution with 2N HCl  to 1L. Prepare just before use. 
(3) Working solution . –Dilute 0,1,5,10, and 20 ml intermediat e solution to 100 ml with 2N HCl  (0, 
0.1,0.5,1.0, and 2.0µg Cd/ml).  
 
(g) Atomic absorption spectrophotometer - With hollow -cathode Cd lamp and 10 cm burner head for 
air – C2H2 flame; wavelength 228.8 nm, range 0 -2.0 µg/ml.  
 
C. Digestion  
Weigh 50.0 g test portion into 1.5 L beaker. Add several bo iling chips or beads, and cover. Carefully add 
25 ml HNO 3, cover, and warm gently with flame to initiate reaction. (Meker - type burners are preferred 
throughout for their versatility and speed). When reaction subsides, add 25 ml HNO 3, warm again, and 
conti nue until 100 ml HNO 3 has been added. (Alternatively, add 100 ml HNO 3 all at once, with caution, 
and let stand at room temperature overnight).  Heat until most NO fumes have evolved; control excessive 
frothing by cooling or quenching with H 2O from wash bot tle. Only some cellulose and fatty materials, if 
any remain undissolved.    AFDC 27 (552) DTZS  
25 
  
To remove any fat visible in hot solution, proceed as follows: Cool beaker in ice, and decant clear, 
aqueous solution from coagulated oils and solids through glass wool pad into 1L b eaker. Add 100 ml H 2O 
to 1.5 L beaker with fat, heat, swirl vigorously to rinse fat, chill, and filter as before. Wash funnel and glass 
wool pad with ca 20 ml H 2O. 
 
Add 20 ml H 2SO 4 to test solution, dilute to ca 300 ml with H 2O, and evaporate over flame un til charring 
begins. When charring becomes extensive, cautiously add 50 % H 2O2, 1 ml at time. Let reaction subside 
before addi ng next portion of oxidant, and never add ˃1 ml at time. Continue additions of H 2O2 until 
solution is colourless . Heat vigorously to SO 3 fumes, adding more H 2O2 as required to remove char. Heat 
vigorously to expel excess H 2O2. Cool colourless  digest to room temperature.  
 
Prepare reagent blank of 100 ml HNO 3, 20 ml H 2SO 4, add same amounts of H 2O as added to test portion. 
Cautiously add same amounts 50 % H 2O2, as above, and remove all HNO 3 from blank. Carry blank 
through same operations as test portion.  
 
D. Extraction  
Add 2 g citric acid to  cooled digest and cautiously dilute to ca 25 ml with H 2O. Add 1 ml thymo blue 
indicator and adjust to ca pH 8.8 by slowly adding NH 4OH while cooling in ice bath, until solution charges 
from yellowish green to greenish blue. Transfer quantitatively to 250 ml separator, using H 2O, dilute to ca 
150 ml.  
 
Cool solution, and extract with two 5 ml portions concentrated dithizone solution, portion shaking 1 - 2 min 
each time. Continue extraction with 5 ml portions dilute dithizone solution until last 5 ml portion d ithizone 
extract shows no change in colour. Combine dithizone extracts in 125 ml separator. Extract H 2O wash 5 
ml CHCl 3 and add this to dithiz one extracts. Add 50 ml 0.2M HCl  to combined dithizone extracts, shake 
vigorously 1 min, and l et layers separate; discard CHCl 3. Quantitatively transfer aqueous solution to sides 
of 400 ml beaker, add boiling chips, and evaporate carefully to dryness. Carefully rinse down of beaker 
with 10 - 20 ml H 2O and again evaporate to dryness.  
 
E. Determination  
Set instrument to  previously established optimum conditions, using air - C2H2 oxidizing flame and 228.8nm 
resonant wavelength. Disso lve dry residue in 5.0 ml 2M HCl  and determine A of test and standard 
solution a gainst 2M HCl  as blank. Flush burner with H 2O between readings . Use scale expansion controls 
to obtain 4 - 10 × expansion, as convenient. Determine Cd from curve of A against µg Cd/ml:  
 
  
 
For concentration˃  2.0 µg Cd /ml, dilute solution with 2M HCl . 
 
   AFDC 27 (552) DTZS  
26 
  
ANNEX C ( Normative ) 
DETERMINATION OF MERCURY IN FOOD BY FLAMELE SS ATOMIC ABSORPTION 
SPECTROPHOTOMETRIC METHOD   
(Rinse all glassware before use with HNO 3 (1+9)  
 
A. Apparatus  
 
(a) Atomic absorption spectrophotometer . Operating conditions: wavelength 253.7 nm, slit width 160 
µm, lamp current 3 ma, and sensitivity scale 2 .5. 
 
(b) Diaphragm pump.  Coat diaphragm and internal parts of pump with acrylic -type plastic spray.  
 
(c) Water condenser . - 12- 18 (id) × 400 mm borosilicate, 24/40 standard taper joint, modified to hold 
6 mm Rasching rings. Fill condenser with Rasching ri ngs to height of 100 ml; then place 20 mm layer of 4 
mm diameter glass beads on top of rings.  
 
(d) Gas inlet adapter . - 24/40 standard taper,  
 
(e) Digestion flask . – 250 ml boiling flask with 24/40 standard taper joint.  
 
B. Reagents  
 
(a) Reducing solution . –Mix 50 ml H 2SO 4 with ca 300 ml H 2O. Cool to room temperature and dissolve 
15 g hydroxylamine sulphate, and add 25 g SnCl 2 in solution. Dilute to 500 ml.  
 
(b) Diluting solution.  To 1 L volumetric flask containing 300 - 500 ml H 2O, add 58 ml HNO 3 and 67 m l 
H2SO 4. Dilute to volume with H 2O. 
 
(c) Magnesium perchlorate . - Drying agent placed in filter flask. Replace as needed. ( Caution : Mg 
(ClO 4)2 is explosive when in contact with organic substance).  
 
(d) Mercury standard solutions.  - (1) Stock solution. – 1000 µg/ml. Dissolve 0.1354 g HgCl 2 in 100.0 
ml H 2O. (2) Working solution . -1 µg/ml. Dilute 1 ml stock solution to 1 L with 0.5M H 2SO 4. Prepare fresh 
daily.  
   AFDC 27 (552) DTZS  
27 
  
 
C. Determination  
Weigh 5.0g test portion into digestion flask; add 25 ml 9M H 2SO 4, 20 ml 7M HNO 3, 1 ml 2% sodium 
molybdate solution, and 5 - 6 boiling chips. Connect condenser (with H 2O circulating through it) and apply 
gentle heat ca 1h. Remove heat and let stand 15 min. Add 20 ml HNO 3-HClO 4 (1+1) through condenser. 
Turn off H 2O circulating through c ondenser and boil vigorously until white fumes appear in flask. Continue 
heating 10 min. Cool cautiously and add 10 ml H 2O through condenser while swirling liquid in flask. Again 
boil solution 10 min. Remove heat and wash condenser with three 15 portions H 2O. 
 
Cool solution to room temperature. Completely transfer digest with H 2O to 100 ml volumetric flask and 
dilute to volume with H 2O. Transfer 25.0 ml aliquot from each test solution to another digestion flask. 
Adjust volume to ca 100 ml with diluting solu tion, B (b) . 
 
Adjust output of pump to ca 2 L air/min by regulating speed of pump with variable transformer. Connect 
apparatus, except for gas inlet adapter. With pump working and spectrophotometer zeroed, add 20 ml 
reducing solution to diluted aliquot. Im mediately connect gas inlet adapter and aerate ca 3 min. (Adjust 
aeration time to obtain maximum A.) Record A, disconnect pressure on “out” side of pump, and open vent 
on filter flask to flush screen. Prepare reagent blank and standard curve by adding 0, 0 .2, 0.4, 0.6, 0.8, 
and 1.0 µg Hg to series of digestion flasks. To each flask,  add 100 ml diluting solution. Finally, add 
reducing and aerate standards as for test solution.  
 
Plot standard curve from least squares linear regression of A against µg Hg, use c alculator which 
performs linear regression. Determine µg Hg in aliquot from curve. If µg Hg determined falls outside range 
of calibration, repeat determination with smaller aliquot of test solution to bring µg Hg into region of 
standard curve. From size of  aliquot used, determine total µg Hg in original test portion.  
 
            
   
 
 
 
 
 
 
 
 
 
 
   AFDC 27 (552) DTZS  
28 
 ANNEX D (N ormative)  
DETERMINATION OF TIN IN FOODS BY ATOMIC ABSORPTION 
SPECTROPHOTOMETRIC METHOD  
 
A. Principle  
Materials are digested with HNO 3 and then H Cl are diluted. Aqueous KCl is added to test solutions and 
standards to reduce positive instrument interference. Sn is determined by AAS at 235.5nm with oxidizing 
N2O-C2H2 flame.  
 
B. Reagents and Apparatus  
 
(a) Atomic absorption spectrophotometer . – With s imultaneous background correction and N 2O-C2H2 
burner.  
(b) Tin standard solutions.  (1) Stock solution .- 1 mg Sn/ml. Dissolve 1.000 g Sn (reagent grade) in ca 
200 ml concentrated HCl, add ca 200 ml H 2O, cool to ambient temperature, and dilute to 1  L with H 2O. (2) 
Working solutions .- 0, 50, 100, 150, and 200  µg Sn/ml. Into each of five 100ml volumetric flasks, pipet 10 
concentr ated HCl, 1.0ml KCl solution, (C ), and 0,  5, 10, 15, or 20  ml Sn stock solution. Dilute to volume 
with H 2O. 
(c) Potassium chloride sol ution. – 10 mg K/ml. Dissolve 1.91 g KCl and dilute to 100ml with H 2O. 
 
(d) Nitric acid . - Concentrated. Test purity of lot by diluting portion 1:4 (v/v) with H 2O and aspirating 
into AA spectrophotometer. Absence of Sn signal indicates suitability for anal ysis. 
 
C. Preparation of Test solutions  
Accurately (±0.01 g) weigh test portion into 250 ml Erlenmeyer: 30 - 40 g juices or drinks, 20 g foods 
containing 50 - 75% H 2O, and 5 -10 g solids or semisolids. Limit fat or oil content to 2 - 4 g and total 
organics to ca 5 g. Dry in oven at 120°C.  
 
Do not add HNO 3 to test portions unless there is time to complete this stage of digestion in the same day. 
Add 30 ml concentrated HNO 3 to flask and, within 15 min, heat gently in hood to initiate digestion, 
avoiding excess ive frothing. Gently boil until 3 – 6 ml digest remains or until residue just begin to dry on 
bottom. Do not let material char. Remove flask from heat. Without delay, continue as follows, including 2 
empty flasks for reagent blanks: Add 25 ml concentration  HCl, and heat gently ca 15 min until bumping 
from evolution of Cl 2 stops. Increase heat, and boil until 10 -15 ml volume remains, using similar flask with 
15 ml H 2O to estimate volume. Add ca 40 ml H 2O, swirl, and pour into 100 ml volumetric flask, rinsing 
once with ca 10 ml H 2O. When HCl is present in digest, test portions may stand overnight or longer.  
 
Pipet 1.0 ml KCl solution into each volumetric flask. Cool to ambient temperature and dilute to vo lume 
with H 2O, adding additional H 2O to approximately compensate for volume of fat in flask. Mix well and filter 
ca 30 -50 ml through dry, medium porosity paper into dry, polypropylene or polyethylene screw -cap bottle. 
Do not filter blanks. Cap bottles unti l analysis. Solutions are stable several months.    AFDC 27 (552) DTZS  
29 
  
D. Determination  
(Caution:  Due to explosive nature of gases, take care when igniting and using flame. Heating tape on N 2O 
regulator may be needed to maintain steady gas flow).  
 
Using 200 µg/ ml standard and  235.5 nm Sn line, optimize spectrophotometer, burner, and flame 
according t o manufacturer’s instructions . Then increase N 2O flow or decrease C 2H2 flow to give oxidizing 
flame; red part should be ca 4 mm above burner slot. This reduces sensitivity but impr oves precision to 0 
± 0.0004 A for blank and gives 0.201 ± 0.001 A for 100 µg/ ml standard. Periodically monitor sensitivity of 
a standard; if sensitivity decreases ˃  20 %, turn off flame and carefully clean burner slot.  
Zero spectrophotometer while aspira ting H 2O but do not adjust zero until after determinations; autozero 
reduce precision. Aspirate H 2O before and after each test, standard, and blank solution. Take three 5 s 
reading for each solution, average, and reference all A measurements to A of H 2O. 
 
Record A for standard, draw calibration curve, and visually check for inaccurate standards. Two times 
blank -corrected A for 50 µg/ ml standard should not differ by more than 3% from blank -corrected A for 
100 µg/ ml standard.  
 
Block standard blank solution with 50 µg/ ml standard, and using ratio of A, calculate concertation of 
standard blank:  
 
            Standard blank, µg/ ml = ( AO/ (Aʹ - AO)) × 50  
 
Where AO and Aʹ refer to blank and mean of readings for 50 µg/ ml. Blocking standard, respectively.  
 
Add st andard blank concertation to nominal standard concentrations to obtain standard concentrations.  
 
Measure A of material blanks for standard blank and calculate:  
 
Material blank, µg/ ml = AO/ Aʹ × true concentration of 50 µg/ ml standard  
 
Where AO and Aʹ refer to blank and 50 µg/ ml standard, respectively. Calculate mean concentration of 
material blanks, B. Determine test solution concentration by one of 2 ways:  
 
(1) Measure A of test solution (maximum 3 solutions) and 50 µg/ ml standard (100 µg/ ml standard,  
depending on test solution concentration level), blocking test solution with standards. Calculate blank -
corrected test solution concentrations:  
   AFDC 27 (552) DTZS  
30 
 Test solutio n concentration, µg/ ml = (A/ Aʹ  x true concentration) – B 
 
Where A and Aʹ refer to test and standard solution, respectively. When high accuracy is not required or 
when calibration curvature is sensitive, use procedure (2) after confirmation that sensitivi ty changes and 
baseline drift are absent during analytical run.  
 
(2) Calibrate using blank and 50, 100, and 150 µg/ ml standards. Run material blanks and test 
solutions, and calculate solution concentrations using either instrument microprocessor or calibr ation 
curve. Calculate mean of sample blank concentrations, B. Calculate blank -corrected solution 
concentrations (µg/ ml) by subtracting B from solution concentrations.  
For both (1) and (2), calculate concentrations in test portions:  
     
 
 
 