TBS/AFDC 2( 65) P3 
ICS 67:250  
 
©TBS _2020  
 
 
DRAFT TANZANIA STANDARD  
 
 
 
 
Specification  for plastic materials for food contacts applications Part 
5: Polystyrene  
 
 
 
 
 
 
 
 
 
 
 
 
TANZANIA BUREAU OF STANDARDS  
 
 TBS/AFDC 2( 65) P3 
ICS 67:250  
 
©TBS _2020  
0. Forewords  
This standard provides a basic guide on the constitution of polystyrene plastics  which is considered 
toxicologically safe and not on the manner of its  actual processing or use. In reporting the result of a test 
or analysis made in accordance with this standard, if the final values observed or calculated, is to be 
rounded off it shall be done in accordance with TZS 4 Rounding off numerical values . 
In the  preparation of this standard assistance has been derived from: US 1666:2017 Polystyrene for its 
safe use in contact with foodstuffs, pharmaceuticals and drinking water -Specification p ublished by 
Uganda National Bureau of Standards (UNBS)  
1. Scope  
1.1 This Tanzania Standard specifies requirements, sampling and test methods for polystyrene (crystal 
and high impact) materials for the manufacture of plastic items u sed in contact with food stuffs  
1.2 This standard does not cover requirements of a pack aging media for a particular foodstuff other than 
toxicological considerations   
2.  Normative references   
The following referenced standards referred to in the text in such a way that some or a ll of their content 
constitutes  requirements of this standards.  For dated references, only the edition cited applies. For 
undated references, the latest edition  of the referenced document (including any amendments) applies.  
AFDC2 (66) P 2: Packaging mater ials for food contact use – Gene ral requirements  
AFDC 2 (231) P1: Specification for plastic materials for food contact applications part 3: colorants  
TZS 2247 Prerequisite Programme on Food Safety -Part 4: Food Packaging Manufacturing  
TZS 4: Rounding off n umerical values  
AFDC 2(229) P1:  Determination of overall migration of constituents of plastics materials and articles  
  intended to come in contact with foodstuffs - Method of analysis   
 3. Terms and definitions  
For the purposes of this standard, the f ollowing terms and definitions may apply   
3.1 polystyrene  
a) homo polymers of styrene produced by the polymerization  of styrene, and  
b) rubber modified polystyrene consisting of basic polymers produced by combining styrene butadiene 
copolymers and/or pol ybutadiene with pol ystyrene either during or after polymerization  of the polystyrene 
such that the finished basic polymers contain a minimum of 75 percent by mass of total polymer units 
derived from styrene monomer  
 TBS/AFDC 2( 65) P3 
ICS 67:250  
 
©TBS _2020  
4. Requirements  
4.1 Basic resin  
to com ply with this stand ard, the styrene polymers defined in 3 shall be made in such a way that they 
contain no ingredients or residuals of ingredients other than those listed in 4.1.1  to 4.1.3.  
4.1.1 Residual monomer  
the maximum of total residual styrene mon omer, when present  shall be 0.1 percent by mass of the 
polymer when tested according to the method prescribed in Annex A.  
4.1.2 Materials  
the material shall comply with the threshold limits of the catalyst, emulsifying agents, suspension agents, 
miscellan eous polymerization  additives and other additives as prescribed in AFDC 2( 231) P 1 
4.1.3 Pigments and colorants  
In case the coloured material is used for food packaging applications, it shall comply with the list and 
limits of the pigments and colorants pr escribed in AFDC  2 (231) P1  
4.2 Overall migration  
 the overall migration limits of  the materials shall be 60mg/ L, Max of the simulant and 10mg/dm2, Max of 
the surface of the material or article, when tested by the method prescribed in AFDC 2(229) P1   
  NOTE: The requiremen ts of this standard are considered fully met when the two requirements  
  mentioned  in 4 are met, that is, basic resin characteristics at 4.1 and overall migration at   
  4.2.  
4.3 Storage and control  
4.3.1 Storage  
Plastics materials i ntended for f ood contact use shall be stored separately from other materials in closed, 
properly identified containers.  
4.3.2 Control  
An authorized  person should  supervise and control the issue of plastics materials to the proce ss or 
manufacturing area a nd should maintain appropriate written records of the issue of such materials.  
Good manufacturing practices  (GMP ) shall be maintained at all times and plant operators and store men 
shall adhere to good hygien ic practice as detailed in TZS  2247   
5. Packing , marking and labeling  
5.1 Packing  
The material should be suitably packed with suitable liner (food grade) in a container as agreed between 
the purchaser and the supplier, in a manner so as to ensure that the items do not become contaminated 
during trans port and stor age.  
5.2 Marking and labeling  
Each package shall be marked legibly and indelibly with the following  
a) Name and type of the material  TBS/AFDC 2( 65) P3 
ICS 67:250  
 
©TBS _2020  
b) Manufacturing date of the material  
c) Expiry  
d) Country of origin   
e) Name of the manufacturer and/or trade mark, if an y.  
f) The packages shall carry the symbol for food grade (Fig. 1 ) or the word “for food grade” on it  
                                                                        
  
                                                                        Fig. 1  
6. Sampling  
The method of drawing representative samples of the material and the criteria for conformity sh all be a s 
prescribed in Annex B.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 TBS/AFDC 2( 65) P3 
ICS 67:250  
 
©TBS _2020  
Annex A  
 
Analytical method for determination of total residual styrene monomer content  
A.1 Gen eral  
This method is suitable for the determination of residual styrene monomer in all types of styrene 
polyme rs.  
A.2 Principle  
the sample is dissolved in methylene chloride. An aliquot of the solution is injected into a gas 
chromatograph y. The amount of  styrene monomer present is determined from the area of the resulting 
peak.  
A.3 Apparatus  
A.3.1 Gas chromato graph.  
Gas chromatograph y with hydrogen flame detector or apparatus of equivalent sensitivity.  
A.3.2 Chromatograph y column  
6.35mm outside diame ter, stainless steel tubing (0.71mm wall thickness), 1.2m in length, packed with 20 
percent polyethylene glyco l (20000 molecular weight) on alkaline treated 60 -80 mesh firebrick.  
A.3.3 Recorder  
Millivolt range of 0 to 1, chart speed of 12.7mm/min.  
A.4 R eagents  
Compressed air, purified; helium gas; hydrogen gas; methylene chloride, redistilled; and styrene 
mono mer, redistilled  
A.5 Operating conditions for the gas chromatograph  
A.5.1 The column is operated at a temperature of 100°C with a helium flow ra te of 82mm/min.  
A.5.2 The hydrogen burner is operated with 1.1kg/cm2 of air pressure and 0.5kg/cm2 of hydroge n 
pressure.  
A.5.3 The attenuation of the hydrogen flame detector is set at 2 x102  
A.6 Standardization   
A.6.1 Prepare a standard solution by weig hing accurately 15 mg to 20 mg of styrene monomer into a 0.06 
kg bottle containing 25.0 mm of methylene chlori de. Cap the bottle tightly and shake to thoroughly mix the 
solution.  TBS/AFDC 2( 65) P3 
ICS 67:250  
 
©TBS _2020  
A.6.2 By means of a microliter syringe, inject 1 µm of the standard solution  into the gas chromatograph. 
Measure the area of the styrene monomer peak which emerges after approximately 12 min  
A.7 Procedure  
A.7.1 Transfer 1g of sample (accurately weighed to the nearest 0.001g) to a 0.06kg bottle and add 
several glass beads. Pipette  25.0mL of methylene chloride into the bottle. Cap the bottle tightly and place 
on a mechanical shaker. Shake until the polymer is completely dissolved. If any insoluble residue 
remains, allow the bottle to stand (or centrifuge at a low speed) until a clea r supernatant layer appears.  
A.7.2 By means of a microliter syringe, inject 3 microliters of the clear supern atant liquid into the gas 
chromatograph.  
A.7.3 Measure the area of the resulting styrene monomer peak. Compare the sample peak area with the 
area produced by the standard styrene monomer solution.  
A.8 Calculation  
Percentage residual styrene monomer  
   
               
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 TBS/AFDC 2( 65) P3 
ICS 67:250  
 
©TBS _2020  
Annex B  
Sampling of Polystyrene  
B.1 General  
B.1.1 In drawing, preparing, stori ng and handling samples, the following precautions and directions shall 
be observed.  
B.1.2 Samples shall not be taken in an exposed place.  
B.1.3 The sampling instrument, wherever applicable, shall be made of stainless steel or any other 
suitable material  on which the material shall have no action. The instrument shall be clean and dry.  
B.1.4 Precautions shall b e taken to protect the samples, the material being sampled, the sampling 
instrument and the containers for samples from adventitious contamination .  
B.1.5 The samples shall be placed in a suitable, clean, dry, air -tight metal or glass containers on which 
the material has no action. The sample containers shall be of such a size that they are almost completely 
filled by the sample.  
B.1.6 Each sample container shall be sealed air -tight with a stopper after filling and marked with full 
details of sampling, suc h as the date of sampling, the month and year of manufacture of the material, etc.  
B.1.7 Samples shall be stored in such a manner that the temper ature of the material does not vary unduly 
from the normal temperature.  
B.2 Scale of sampling  
B.2.1 Lot  
In a single consignment all the packages of the same class, same type, same form and belonging to the 
same batch of manufacture shall be grouped toge ther to constitute a lot. If a consignment is known to 
consist of packages belonging to different batches of m anufacture or different forms, the packages 
belonging to the same batch of manufacture and same form shall be grouped together and each su ch 
group  shall constitute a lot. The packages may consist of containers of polystyrene materials, rolls, films, 
vials,  etc.  
B.2.2 Sample size  
For ascertaining the conformity of the material to the requirements of this specification, samples shall be 
tested from each lot separately. The number of packages to be sampled shall depend on the size of the 
lot and shall be in accordance with Table B 1.  
Table B1 — scale of sampling  
Lot size  For visual examination  
(See 8.1)  For closure leakage test  
(see 9.1 and 9.3)  For dimensional examination  
(See 7.2 and 7.3)  
Sample size  Acceptance   
Number  Sample 
size  Acceptance   
Number  No. of Samples  
Up to 500  13 1 5 0 2 
501-1000  20 2 8 0 2 
1001 -3000  32 3 13 0 2 TBS/AFDC 2( 65) P3 
ICS 67:250  
 
©TBS _2020  
3001 -5000  50 5 20 1 3 
5001 and 
above  80 7 32 2 5 
B.2.2.1 Thes e packages shall be selected at random from the lot in accordance to the relevant Tanzania 
standards for  sampl ing 
B.3 Preparation of test samples  
B.3.1 From each of the packages of material selected, small portions of material shall be drawn with the 
help of a suitable sampling instrument. The total quantity of material collected from each package shall be 
suffic ient to test all the requirements given in 4.  
B.3.2 In the case of packages consisting of containers, vials, rolls or films, the number of items to be 
selected from a package, for testing each of the requirements given in 4, shall be one.  
B.4 Number of t ests  
Tests for determining all the requirements given in 4 shall be carried out on the individual test samples.  
B.5 Criteria for conformity  
the lot shall be declared as conforming to the requirements of this specification if all the test results on 
individual samples meet the relevant specification requirements