AFDC  9 (1530 ) DTZS   
 
 
 
 
DRAFT TANZANIA  STANDARD  
 
Limestone for animal feed  – Specification  
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
TANZANIA BUREAU OF STANDARDS  
                                                   
Limestone for animal feed – Specification  
 
0 Foreword  
 
Limestone is the mos t common source of C alcium used in livest ock feeding. It is almost pure 
Calcium carbonate  (CaC O3). Calc itic limestone contains minimum 36% C alcium and can 
safely be fed free choice (ad lib) mixed with salt. Dolomitic l imestone contains at least 5 % 
Magnesiu m C arbonate and should not be used for poultry, but it is as good as calcitic 
limestone for other animals.  
 
This Tanzania standard would help in exercising proper quality and safety control for 
limestone , produced or traded in the country for feeding dome sticated animals.  
 
In prepar ation of this Tanzania  standard considerable assistance ha s been derived from 
C706-19 Standard Specification for Limestone for Animal Feed Use  developed by American 
Society for Testing and Materials . 
 
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).  
 
1.0   Scope  
 
This draft Tanzania standard specifies  requirements , method s of sampling and test for 
limestone intended for use as a mineral supplement in animal feeds.  
 
2.0   References  
 
For the purpose of this finalized Tanzania Standard, the following references shall 
apply. For dated references, only the edition cited applie s. For undated references, the latest 
edition of the referenced document (including any amendments) applies.  
 
TZS 4 – Rounding off  numerical values . 
TZS 34 -3 – Animal feeds and feeding stuffs – Part 3 – Microbiological test methods.  
TZS 34 -2 – Animal feeds  and feeding stuffs – Sampling and test methods – Part 2: Minerals 
and trace elements.   
TZS 34 -1 – Animal feeds and feeding stuffs – Part 1 Sampling and general methods .  
TZS 76 – General method for determination of Arsenic silver diethyldithiocarmate phot ometric 
method.  
TZS 109 – Food Processing units – code of hygiene – General.  
TZS 268 – General atomic absorption spectrophotometric method for determination of lead in 
food stuffs  
TZS 538:1999 – Packaging and labeling of foods  
TZS 821  – Animal feeds and fe eding stuffs – Preparation of test samples.  
ISO 5985 – Animal feeding stuffs – Determination of ash insoluble in hydrochloric acid . 
AOAC  2006.03 -2009 – Arsenic, Cadmium,Cobalt,Chromium,Lead,Molybdenum,Nickel,and 
selenium in fertilizers  
 
3.0   Terms and de finitions  
 
For the purpose of this finalized standard, the following terms and definition s shall apply:  
 
3.1 dolomite    
limestone or marble rich in magnesium carbonate  
  
3.2 calcitic   
common crystalline form of natural calcium carbonate (CaCO 3), that is the  basic constituent 
of limestone, marble, and chalk  
 
4.0   Requirements  
 
4.1 General requirements  
4.1.1  Limestone shall be suitable for animal feeding.  
4.1.2  Particle size analysis and other physical requirements shall be specified by the 
purchaser.   
 
 
4.2 Specific requirements  
Limestone  shall conform to the requirements prescribed in Table 1.  
Table 1: Physico -chemical requirements  
S/No
. Limestone 
Classes  Calcium, 
(as CaCO 3) 
Min,%  Magnesium 
(as MgCO 3) 
max, %  Magnesium 
(as MgCO 3) 
min, %  Moisture, 
max, %  Test 
methods  
1 High Calcium  95 5 - 0.5  
 
TZS 34 -2 
 2 Magnesian  60 35a 5 0.5 
3 Dolomitic  49 46a 35 0.5 
4 Ground 
limestone  82 b b 0.5 
 
a The high magnesium content of these materials usually limits their use to special -purpose feeds.  
b as specified by t he purchaser  
  
 
5.0 Contaminants  
 
The products covered by this  Standard shall comply with the maximum limits for heavy 
metals specified in Table 2 . 
 
Table 2:  Heavy metal contaminant s 
S/No. Heavy metal  Limits  Method of test  
(see clause 2)  
i) Mercury (Hg) , mg/kg , max  0.1 AOAC 2006.03  
ii) Lead (Pb), m g/kg, max  15 TZS 268  
iii) Arsenic (As), mg/kg, max  10 TZS 76  
iv) Cadmium (Cd), mg/kg, max  10  AOAC 2006.03  
 
 
6.0 Hygiene  
 
6.1 The product shall be prepared under strict hygienic conditions according to TZS 109 (see 
clause 2) . 
 
6.2 The product on testing shall not contain the listed micro organisms given  in Table 3 . 
  
Table 3: Microbiological limits  
S/No.  Microorganisms  Limit  Methods of test (see clause 2)  
i) Bacillus anthracis  Absent  TZS 34 -3 
ii) Clostridiu m sp p. Absent  TZS 34 -3 
 
7.0 Sampling and tests 
 
7.1 Sampling  
Sampling of the product covered under this standard shall be done according to TZS 34 -1 
(see clause 2).    
 
7.2 Tests  
Testing of limestone  shall be done according to test methods prescribed in Table  1, 2 and 3 
(see clause 2).   
 
8.0 Packaging, marking and labelling  
 
8.1 Packaging  
Limestone  shall be package in moisture –proof bags, cartons, boxes or drums. All containers 
shall be sound, clean and free from causal agents of infectious diseases and paras ites.   
 
8.2 Marking  and labelling  
In addition to marking and labelling requirements prescribed in TZS 538 , limestone for each 
packag e shall be marked to display the following information:  
 
a) Name of the product – “Limestone ”; 
b) Name and address of the manufac turer;  
c) Country of origin  
d) Batch or code number;  
e) Date of production;  
f) Net weight in metric units ; 
g) Expiry date ; 
h) Storage conditions ; 
i) Directions for use;  
j) The percentage of calcium ; and 
k) Trade name or brand name if any.  
 
 
8.3 The container may also be marked wit h TBS Certification Mark.  
NOTE  – The TBS Standards Mark of Quality may be used by the manufacturers 
only under licence from TBS. Particulars of conditions under which the licences 
are granted may be obtained from TBS.