AFDC06 (2346)DTZS   
ICS 67.100.10  
 
© TBS 2023                                                                                                                              First Edition 2023  
 DRAFT TANZANIA  STANDARD  
Fortified yoghurt – Specification  
TANZANIA BUREAU OF STANDARDS  
 
 
 
 
 
 
 AFDC06 (2346)DTZS  
ii © TBS 2023 – All rights reserved  
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 AFDC06 (2346)DTZS  
© TBS 2023 – All rights reserved  iii 
  
0. Foreword  
Fortified yoghurt is product made from coagulation of milk by adding thermophilic starter culture with the 
addition of micronutrients.  
The fermentation is carried out by the mixed cultures of Lactic acid bacteria or any other suitable cultures. 
Fortified yoghurt may be a plain or sweetened and/or flavored dairy product.  
This draft Tanzania standard has been developed to keep up with advancements of the fo od industry and to 
enhance nutrition value of this product content as well as ensure the safety and quality of the product traded in 
the markets in order to safeguard the health of the consumers.  
In preparation of this Tanzania standard assistance has been  derived from TZS 307 :2020 /EAS 33:2019 for 
Yoghurt – Specification developed by East African Community.  
In reporting the results of a test or analysis made in accordance with this standard, if the final value, observed 
or calculated, is to be rounded off, it shall be done in accordance with TZS 4 (see clause 2).  
 
 AFDC06  (2346) DTZS    
 
© TZS 2023 – All rights reserved  
  
 1 Scope   
This draft Tanzania standard specifies requirements, sampling and test methods for fortified  yoghurt  obtained 
by lactic acid fermentation through the action of Lactobacillus bulgaricus  and Streptococcus thermophil lus 
intended for human consumption . 
2 Normative references   
For the purpose of this draft Tanzania standards , the following references shall apply. For dated references, 
only the edition cited applies. For undated references, the  latest edition of the referenced document (including 
any amendments) applies.  
CXS 192, Codex general standard for food additives  
CXS 193, General Standard for Contaminants and Toxins in Food and Feed  
TZS 4 , Rounding off numerical values  
TZS 100, Plantain (mill) white sugar  
TZS 109, Food processing units – Code of hygiene TZS 122, Microbiology of the food chain — Horizontal 
method for the detection, enumeration and serotyping of Salmonella — Part 1: Detection of Salmonella spp.  
TZS 125 -3, Microbiology of fo od and animal feeding stuffs — Horizontal method for the enumeration of 
coagulase -positive staphylococci (Staphylococcus aureus and other species) — Part 3: Detection and MPN 
technique for low numbers  
TZS 251, Pasteurised milk — Specification  
TZS 481, Nutr ition labelling — Requirements  
TZS 538, Labelling of pre -packaged foods — General requirements  
TZS 635, Milk and milk products – Guidance on sampling and methods of test  
TZS 730, Microbiology of food and animal feeding stuffs — Horizontal method for the de tection and 
enumeration of presumptive Escherichia coli — Most probable number technique  
TZS 799, Foodstuffs — Determination of aflatoxin B1, and the total content of aflatoxins B1, B2, G1 and G2 in 
cereals, nuts and derived products — High-performance liq uid chromatographic method  
TZS 902, Yoghurt — Enumeration of characteristic microorganisms — Colony count technique at 37 degrees 
C 
TZS 950, Milk and milk products — Enumeration of colony -forming units of yeasts and/or moulds — Colony -
count technique at 2 5 degrees C  
TZS 963 -3, Starch and derived products - Heavy metals content -3- Determination of lead content by Atomic 
Absorption  Spectrophotometry with electro -thermal atomization   
2 © TBS 2023 – All rights reserved  
 TZS 1390 -3, Milk products and milk based foods –Determination of fat content by Weibull -Berntrop 
gravimetric method Part 3: Special cases  
TZS 1485, Infant Formula - Determination of mineral content by atomic absorption spectrophotometric method  
TZS 1507, Milk based Infant formula — Determination of vitamin D3 content by liquid chrom atography -mass 
spectrometry  
TZS 1994, Infant formula and adult nutritionals — Determination of vitamin E and vitamin A by normal phase 
high performance liquid chromatography  
TZS 1995, Infant formula and adult nutritionals — Determination of vitamin B12 by reversed phase high 
performance liquid chromatography (RP -HPLC)  
TZS 3705,  Ice-cream and milk ice - Determination of total solids content (Reference method)  
3 Terms and definitions   
For the purposes of this standard, the following terms and definitions shal l apply.  
3.1 
yoghurt  
milk product obtained by lactic acid fermentation through the action of Lactobacillus bulgaricus  and 
Streptococcus thermophilus  
3.2 
sugar  
any carbohydrate sweetening matter in crystal form  
3.3  
fortificants  
vitamin and minerals intende d to be added to yoghurt  
 
3.4 
yoghurt fortification  
practice of deliberately adding micronutrients in yoghurt so as to improve the nutritional quality .  
 
3.5 
sweetened fortified yoghurt  
fortified yoghurt to which sugar has been added  
3.6 
plain fortified y oghurt  
fortified yoghurt to which no sugar has been added  
3.7 
flavoured fortified yoghurt  
fortified yoghurt to which flavouring agents have been added  
  
© TBS 2023 – All rights reserved  3 
 3.8 
fruit fortified yoghurt  
fortified yoghurt to which fruits or fruit pulp have been added  
3.9 
probioti c fortified yoghurt  
fortified yoghurt which contains in addition to yoghurt starter culture (Lactobacillus bulgaricus  and 
Streptococcus thermophilus ),other  live lactic acid bacteria  which when administered in adequate amounts, 
confer a health benefit on th e host  
 
3.10 
greek fortified yoghurt  
fortified yoghurt that has been strained to remove its whey resulting to a thicker and creamy consistency  
3.11 
food grade packaging material  
packaging material made of substances which are safe, and suitable for their i ntended use and which will not 
alter the quality, safety or organoleptic properties of the product  
4 Types and Categories of fortified yoghurt  
4.1 Types of fortified yoghurt  
The following are the various types of fortified yoghurt including but not limited  to: 
a) plain fortified yoghurt;  
b) flavoured fortified yoghurt;  
c) probiotic fortified yoghurt.  
4.2  Categories of fortified  yoghurt  
The categories based on fat content shall be as follows:  
a) whole milk fortified yoghurt;  
b) low fat milk fortified yoghurt;  
c) fat free mil k fortified yoghurt; and  
d) high fat milk fortified yoghurt.  
 
5.0 Requirements  
5.1 Ingredients  
All food ingredients used in the preparation of fortified yoghurt shall comply to specific national standard.  
5.1.1 Essential ingredients  
All fortified yoghurts sh all be made from the following ingredients:  
a) milk and milk products which may include any of the following:  
(i) raw milk   
4 © TBS 2023 – All rights reserved  
 (ii) skimmed milk  
(iii) thermized/pasteurized/ sterilized whole milk   
(iv) pasteurized skimmed milk complying with TZS 251 ; 
(v) reconstituted or recombined;  
(vi) evaporated or condensed milk, whole or skimmed;  
(vii) a mixture of two or more milk products.  
(viii) starter culture  
5.1.2 Optional ingredients  
5.1.2.1  Ingredients, including but not limited to the following, may be added to all types of fortified yoghurts:  
a) unfermented  butter milk;  
b) concentrated whey;  
c) whey or whey proteins and/or their concentrates;  
d) edible casein and caseinates;  
e) sugars (in sweetened types of yoghurt only), complying with TZS 100; or  
f) flavouring agents, nutritive and non -nutritive sweeteners, stabilisers, thickeners, fruits, vegetables as 
well as juices, purees, pulps and preparations and preserves derived therefrom, cereals, honey, 
chocolate, nuts, coffee, spices and other harmless natural flavouring foods and/or flavours.  
g) pasteurized cream/butter/cream;  
5.1.2.2  Where non -dairy ingredients are used, they shall not be more than 5 % of the total composition.  
5.2 Fortificants  
Fortified yoghurt shall comply with the fortificants level requirements specified in Table 1.  
Table 1 - Requirements for levels of for tificants in fortified yoghurt.  
S/N Micronutrient  Required level 
(μg/100g)  Test methods  
1 Vitamin A  109 - 227 TZS 1994  
2 Folic Acid  
 31.5 - 49.2 TZS  1485  
3 Vitamin B 12 
 0.3 - 0.82 TZS 1995  
4 Vitamin  D  
 1.0 - 2.6 TZS 1507   
© TBS 2023 – All rights reserved  5 
 5 Iodine  
 26.6 - 66.4  
TZS 1485  
 6 Selenium  
 4.3 - 10.7 
7 Zinc 836 - 2090  TZS 1485  
Note: Fortified yoghurt shall be added with at least  three (3) micronutrients 
indicated in Table 1  
5.3 General requirements  
Fortified yoghurt shall:  
a) be free from off odours and off flavours such as metallic flavour or yeast flavour;  
b) be free  from foreign matter; and  
c) have the characteristic texture and taste of the type of fortified yoghurt. 5.4 Specific requirements  
Fortified yoghurt shall comply with the requirements specified in Table 2 when tested in accordance with the 
test methods spec ified therein.  
Table 2 ▬ Specific requirements for fortified yoghurt  
S/N Characteristic  Requirement  Test method  
Whole milk 
fortified 
yoghurt  Low fat milk 
fortified  
yoghurt  Fat free milk 
fortified 
yoghurt  High fat 
milk 
fortified 
yoghurt  
i.  Milk fat con tent, %, 
m/m 3.25 - 4.5 0.5 - 2.70 < 0.5  4.6 - 15 TZS 1390 -3 
 
ii.  Milk solids non -fat, 
%, m/m, min.  8.5 8.5 8.5 8.5 TZS 3705  
 
iii.  pH 4.2 - 4.6 4.2 - 4.6 4.2 - 4.6 4.2 - 4.6 Annex A  
iv.  Titratable acidity, 
%, as lactic acid, 
min. 0.6 - 1.0 0.6 - 1.0 0.6 - 1.0 0.6 - 1.0 Annex B  
v.  Sum of 
microorganisms 
constituting the 
starter culture, 
CFU/g in totala 107 107 107 107 
 
TZS 902  
vi.  Labelled 
microorganisms  
CFU/g in totalb 106 106 106 106 
a The requirement on sum of microorganisms and labelled microorganisms  do not appl y for heat treated 
yoghurt  
b Applies where a content cream is made in the labelling that refers to the presence of a specific 
microorganism other than Lactobacillus bulgaricus  and Streptococcus thermophilus  that has been added as 
supplement to the specifi c starter culture   
6 © TBS 2023 – All rights reserved  
 6.0 Hygiene  
6.1 Fortified yoghurt shall be produced and handled in accordance with TZS 109 . 
6.2 Fortified yoghurt shall comply with microbiological limits in Table 3 when tested in accordance with the 
test methods specified therein.  
Table 3 — Microbiological limits for fortified yoghurt  
S/N Micro organisms  Maximum limit  Test method  
i.  Escherichia coli, CFU/g  Absent  TZS 730  
 
ii.  Salmonella spp, per 25 g  Absent  TZS 122  
 
iii.  Staphylococcus aureus , per 
g Absent  TZS 125 -3 
 
iv.  Moulds and yeasts , CFU/  g 102 TZS 950  
 
 
7.0 Food additives  
Food additives which may be used shall comply with CXS 192.  
8.0 Contaminants  
8.1 Pesticide residues  
Fortified yoghurt shall comply with maximum limits residues set under Codex Alimentarius Commission online 
database for  pesticide residue.  
8.2 Veterinary drugs residues  
Fortified yoghurt shall comply with maximum tolerable residue limits for antibiotics and other veterinary drugs 
set by Codex Alimentarius Commission.  
8.3 Heavy metals  
When tested in accordance with TZS 963 -3 the level of Lead (Pb) shall not exceed 0.02 mg/kg.  
8.4 Mycotoxins  
When tested in accordance with TZS 799, the level of aflatoxin M1 shall not exceed 0.50 µg/kg.  
9.0 Packaging  
Fortified yoghurt shall be packed in food grade packaging material that safeg uards the integrity and safety of 
the product and the environment.   
© TBS 2023 – All rights reserved  7 
 10.0  Labelling  
10.1  The package shall be labelled in complia nce with the requirements of TZS  538 and  TZS 481 . In 
addition, the following particulars shall be legibly and indelibly labelle d on the package:  
a) name of the product as “Fortified yoghurt” by type  and categories based on fat content  in accordance with 
clause 4;  
b) net content in SI units;  
c) name and physical address of manufacturer;  
d) batch or code number;  
e) nutritional infor mation;  
f) date of manufacture and expiry date;  
g) instruction for storage and use;  
h) declaration of allergens, if any; and  
i) Instruction for disposal of used package  
j) list of ingredients  
k) list of fortificants  
11.2 The label shall carry the picture of the fruit, nuts, confectionary and their derivatives only when yoghurt 
contains the real fruit, nuts, confectionary and/or their derivatives.  
12 Sampling  
Sampling of fortified yoghurt shall be done in accordance with TZS 635.   
8 © TBS 2023 – All rights reserved  
 Annex A  
(Normative  
 
Determi nation of pH  
A.1 General  
The pH value or hydrogen ion concentration gives a measure of the true acidity of yoghurt. The relationship 
between pH and acidity of yoghurt is only approximate. In yoghurt the pH ranges from 4.2 to 4.6. The value is 
reduced by th e development of acidity. The pH of yoghurt may be determined rapidly by using the indicator 
strips.  
A.2 Indicator strips  
Indicator paper strips or discs are made by soaking strips of absorbent paper in a suitable indicator and drying 
them.  
A rough estimat e of pH is obtained by dipping a strip of the prepared paper in yoghurt and observing the 
colour. Bromocresol purple (pH range 4 to 7, colour changes from yellow to purple) and bromothymol blue (pH 
range 4 to 7, colour changes from straw yellow to bluish -green) are commonly used as indicators. Both narrow 
and wide range ready -made indicator papers are available over the pH range 2.0 to 10.5.  
Indicator paper strips shall always be kept in closed containers and under dry conditions.  
A.3 pH meter  
The pH meter may be used to determine pH in yoghurt  
A.4 Interpretation  
On an average, yoghurt gives a pH of 4.6. Yoghurt of pH over 4.6 should be regarded with suspicion as 
indication of poor fermentation as a result of starter culture inhibition. pH below 4.2 is as a result of over 
fermentation.   
© TBS 2023 – All rights reserved  9 
 Annex  B 
(normative)  
Determination of titratable acidity  
B.1 Apparatus  
B.1.1  Incubator  
B.1.2  Burette , with soda -lime guard tube  
B.1.3  Porcelain dishes , white hemispherical of app roximately 60 ml  
B.1.4  Stirring rods , of glass, flattened at one end  
B.2 Reagents  
B.2.1  Standard sodium hydroxide solution  
Prepare concentrated stock solution of sodium hydroxide by dissolving equal parts of sodium hydroxide 
(stocks or pellets) in equal pa rts of water in a flask. Tightly stopper the flask with a rubber bung and allow any 
insoluble sodium carbonate to settle down for three to four days.  
Use the clear supernatant liquid for preparing the standard 0.1 M solution. About 8 ml of stock solution i s 
required per litre of distilled water. The solution should be accurately standardized against acidic potassium 
phthalate or oxalic acid.  
B.2.2  Phenolphthalein indicator solution  
Dissolve 1 g of phenolphthalein in 110 ml rectified spirit. Add 0.1 M sodium  hydroxide solution until one drop 
gives a faint pink coloration.  
B.2.3  Rosaniline acetate stock solution  
Dissolve 0.121 g of rosaniline acetate in approximately 50 ml of rectified spirit, containing 0.5 ml of glacial 
acetic acid. Make up to 100 ml with re ctified spirit.  
B.2.4  Bench solution  
Dilute 1 ml of stock solution to 500 ml with a mixture of rectified spirit and distilled water in equal proportions 
by volume.  
The stock and the bench solutions shall be stored in dark brown bottles securely stoppered w ith rubber bungs.  
B.3 Procedure  
B.3.1  Acidity of fresh sample  
Weigh 10.0 g of the sample into each of the two white porcelain dishes of approximately 60 ml capacity; add 
to both 10 ml of water and stir to disperse the sample. Prepare from one dilution a co lour control by adding 
and stirring 2 ml dilute rosaniline acetate solution. Stir 2 ml phenolphthalein solution into the other dilution and 
while stirring vigorously, add as rapidly as possible sodium hydroxide solution from a 10 -ml burette fitted with 
a soda-lime guard tube, until the colour matches the pink colour of the control. The titration shall be done in 
bright light.   
10 © TBS 2023 – All rights reserved  
 B.3.2  Acidity after incubation  
Incubate another 20 g of sample at 55 °C ± 1 °C for five days. Examine the flask each day, then shake and 
replace it in the incubator. If any physical alteration (as indicated in A.2.1) of the content is observed the 
results of the test shall be considered positive and the sample as non -sterile.  
If no alteration takes place during the five days incubation remove the sample from the incubator and cool to 
room temperature. Weigh 10 g of the incubated sample and determine acidity as described in B.3.1.  
B.4 Calculation  
B.4.1  Acidity of fresh sample  
Titratable acidity (as lactic acid) per cent by weight = 
mMV.9  
where  
V is the volume, in millilitres, of the standard sodium hydroxide required for titration (see B.3.1)  
M is the molarity of the standard sodium hydroxide solution (see B.3), and  
m is the mass, in grams, of the sample taken for test (s ee B.3.1).  
B.4.2  Acidity after incubation  
B.4.2.1  Titratable acidity (as lactic acid) percent by weight =  
wMV.9  
where  
V is the volume, in millilitres, of the standard sodium hydroxide required for titration (see B.3.2.1),  
M is the molarit y of the standard sodium hydroxide solution (see B.3.2.1),  
w is the weight, in grams, of the sample taken for the test (see B.3.2.1)  
B.4.2.2  Subtract the value obtained in B.4.1 from the value obtained in B.4.2 which would give increase in 
acidity.  
B.5 Interpretation of results  
A sample which does not show any physical alteration during incubation at 55 °C ± 1 °C for five days and 
where the acidity does not show a difference of more than 0.02 g from the initial acidity is considered sterile.   
© TBS 2023 – All rights reserved  11 
 Bibliography  
[1] TZS 307: 2020 (3rd Ed) EAS 33:2019 Yoghurt – Specification