KENYA STANDARD                                          KS 2745: 2017 
ICS67.140.10 
 
 
  
 
  
 
  
 
  
 
  
 
 
Purple tea — Specification  
 
 
 
 
  
 
  
 
  
 
  
 
  
 
  
 
  
 
  
 
  
 
  
© KEBS 2017FirstEdition2017KS 2745: 
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TECHNICAL COMMITTEE REPRESENTATION 
 
The following organizations were r epresented on the Technical Committee. 
 
Egerton University  
Agriculture and Food Authority- Tea Directorate Ministry of Health — Food Safety Unit 
Government Chemist’s Department 
Melvin Mash International Ltd Unilever Tea Kenya Ltd 
Kenya Plant Health inspectorate Service 
James Finlay (Kenya) Limited 
Kenya Agricultural and Livestock or ganization -Tea Research Institute 
Ministry of industry, Trade and cooperatives Ministry of Agriculture, Livestock and Fisheries 
Kenya Tea Development Agency Ltd 
Institute of Packaging of Kenya Consumer Information Network 
Gold crown beverages-Kenya LTD 
Karatina University Kenya Bureau of Standards- Secretariat 
 
 
 
 
 
 
 
  
 
 
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 KENYA STANDARD                                                KS 2745: 2017 
ICS67.140.10  
 
 
 
  
 
  
 
  
 
  
 
  
 
Purple tea — Specification  
 
 
  
 
  
 
  
 
  
 
  
 
  
 
  
 
  
 
  
 
KENYABUREAUOF STANDARDS(KEBS)  
 
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Coast Region  Lake Region  Rift ValleyRegion  
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Fax: (+254 041) 229448 Fax: (+254 057)21814  KS 2745 
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Foreword  
 
ThisKenyaStandardhasbeenpreparedbytheTeaTechnicalCommitteeundertheguidanceoftheStandardsProjects 
Committee and it is in accordancewiththe procedures ofthe Kenya Bureau of Standards.  
Tea is grown and manufactured in numerous countries of the world and is blended or consumed in many more. 
Purple tea may be produced from tea from more than one garden or region or may be a blend of teas from twoor 
more origins. 
The objective of this Standard is to specify the plant sour ce from which the purple tea is to be manufactured and to 
set requirements for certain physical, chemical and microbi ological characteristics which, if met, are an indication 
that the tea had been subjected to good production practice. 
The desired characteristics of a purple tea and the resulti ng liquor depend upon many fact ors including; thetype of 
water to be used for brewing, the preparation method and on individual tastes. It is a matter for the parties concerned to apply the requirem ents of this Standard to aconsignment or lot of purple 
tea. The quality of purple tea is usually assessed organolept ically by skilled tea tasters,  who base their judgements 
on their previous experience of purple  tea, their knowledge of theconditions in the producing areas, and the 
preferences of the consuming country. Account may be taken ofcharacteristic s such as the appearance of the tea 
before preparation of liquor (such as shape, colour,clean liness, and evenness), the appear ance of the infused leaf 
and the appearance, odour, and taste of theliquor. In practice, teas are submitted for physical, chemical and microbiological analysisto ascertain conformity.  
 
 
This Kenya Standard also specifies the packing and ma rking requirements for purple tea in containers. 
 
 
During the preparation of this standard, refere nce was made to thefollowing documents:  
 
ISO 11257: Green tea — Definitions andbasic requirements.  
 
 
Acknowledgement is herebymade for theassistance derived from these sources. 
 
 
.  
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 KENYASTANDARD                                                                     KS 2745: 2017 
 
 
 
Purpletea - specification  
 
1 Scope 
 
This Kenya Standard specifies the parts of Camelliasinensis (L inneaus) O. Kuntzesuitable for making purple tea for 
consumption as a beverage and the chemical requirements used to indicate that tea from that source has been 
produced in accordance with good production practice. This standard does not apply to flavoured teas and 
decaffeinated purple teas. 
 
 
2       Norm ativereferences 
 
The following referenced documents are indispensable fo r the application of this Kenya Standard. For dated 
references, only the edition cited applies. For undated re ferences, the latest edition of the referenced document 
(including any amendments) applies. 
 
ISO 1572, Tea — Preparation of ground sample of known dry matter content 
ISO 1573, Tea — Determination of loss in mass at 103 °C ISO 1575, Tea — Determination of total ash 
ISO 1576, Tea — Determination of water-soluble ash and water-insoluble ash 
ISO 1577, Tea — Determination of acid-insoluble ash 
ISO 1578, Tea — Determination of alkalinity of water-soluble ash 
ISO 1839, Tea — Sampling ISO 5498, Agricultural food products — Determinat ion of crude fibre content — General method 
ISO 9768, Tea — Determination of water extract 
ISO 14502-1, Determination of substances characteristic  of green and black tea — Part 1: Content of total 
polyphenols in tea — Colorimetric me thod using Folin-Ciocalteu reagent 
ISO 14502-2, Determination of substances characteri stic of green and black tea — Part 2: Content of 
catechins in green tea — Method using high-performance liquid chromatography 
ISO 15598, Tea — Determination of crude fibre content 
AOAC 2005.02; Method for the determination of anthocyanins 
KS ISO 11286;Teaclassification by particlesize 
 
3 Terms and definitions 
For the purposes of this document, the following terms and definitions apply. 
  3.1Purple tea 
Tea derived from the tender leaves, buds , and shoots of varieties of the species Camellia sinensis (L.) O. Kuntze, 
known to be suitable for making tea for consumption as a bev erage. Purple tea is derived from tea varieties whose 
leaves have purple colouration due to anthocyanin and pr oduced by acceptable processes including aeration, semi 
aeration and non-aeration.  
 
3.2 Extraneous matter 
 
Any material of tea origin such as twigs, barkand stems 
   
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 3.3 Foreign matter 
 
Any material which is not tea leaf, fl avour used or fragments of tea plant e. g. sand, stones, me tallic chips and any 
organic matter other than extraneous matter  
 
3.4 Contaminants 
 
Any physical or chemical or biological agent, foreign matte r, or any other substances not intentionally added to 
food which may compromise food safety or suitability 
 
3.5 Adulterant 
 
Any material intentionally added that changes the origi nal composition and compromises the quality and safetyof 
black tea 
 
3.6 Filth 
 
Any material such as, but not limited to dead insects, rodents and their derivatives 
 
3.7 Taint  
 
Taste and odour foreign to tea 
 
 
4       Requirements  
 
4.1     Generalrequirements  
 
Purple teashall comply withthe following: 
 
4.1.1 The tea shall be clean and reasonably free from extraneous matter when inspected visually. 
 
4.1.2 The tea shall be free from taint, and shall have the charac teristics, appearance, colour  and taste of purple tea, 
when examined by sensory analysis.  
4.1.3 The tea shall be free from any additives such as colouring agents and flavourings. 
  
4.2 Chemical requirements 
 
4.2.1 The tea shall comply with the requirements specified in Table 1 using the methods quoted, in which all 
the figures given are expressed on the basis of material oven dried to constant mass at (103 2) °C by the 
method specified in ISO 1573.  
4.2.2 If no limit is specified for the moisture content of the tea,  the actual loss in massat 103 °C of the sample may 
be determined and the result recorded in the test report. In  suchcases, the determination shall be carried out by the 
method described in ISO 1573. 
 4.2.3 Liquor for sensory assessment can be prepared by the method specified in ISO 3103. The assessment shall be 
described in the test report using terms defined in ISO 6078 
4.2.3 Compositionalqualityrequirements/limits  
 
The Purple tea shallcomplywith the requirements/limits specified in Table 1. 
   
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 Table 1 ▬ Chemical requirement for purpletea. 
 
SL No.  Characteristic   Requirement   Methods of te
   Aerated   Non aerated  
(i) Moisture content %, m/m 7.0max 7.0max KS ISO 157 3
(i)  Water extract, % mass fraction   32 min.   32 min.  ISO 9768  
(ii)  Total ash, % mass fraction.   8 max 
4 min. 8 max 4 min. ISO 1575
 
(iii)  Water-soluble ash, % mass fraction of total ash   45 min  45 min ISO 1576  
(vi)  Alkalinity of water-soluble ash (as KOH), % mass 
fraction  1,0 mina 
3,0 maxa 1,0 mina 
3,0 maxa ISO 1578  
(v)  Acid-insoluble ash, % mass fraction   1.0 max.   1.0 max.  . ISO 1577
(iv)  Crude fibre, % mass fraction   16,5 max  16,5 max  ISO 5498 or ISO 1
(vii)  Total catechins, % mass fraction   3min.   7 min.  ISO 14502-2
(viii)  Total polyphenols, % mass fraction   19 min  22min  ISO 14502-1
(ix)  Ratio total catechins to  total polyphenols, mass fraction  0.2 min. 0.3 min.   
(x)  Total monomeric anthocyaninns, mg/L 14 min 75 min AOAC 2005.0
NOTE 
a When the alkalinity of water-soluble ash is expressed in terms of millimoles of KOH per 100 g of  ground sample, the limits sha ll be:17,8 min ;
max. 
b The specific method for the det ermination of crude fibre in tea is specified in ISO 15598; however, for the purpose of routine estimation, the g
method specified in ISO 5498 is adequate. In cases of dispute, the method of determi nation should always bethat specified in IS O 15598. Th e
requirement remains unchanged, regardless of the method used. 
 
  
 
5.    CONTAMINANTS  
 
5.1Purple tea shall comply with maximum levels of the Codex General standard for contaminants and toxins in 
Food and feed (CODEX STAN 193-1995) 
 
5.2Pesticides  
Purple tea shall comply with maximum residue limits  for pesticides established by the Codex Alimentarius 
Commission in the Codex General standard for contaminants and toxins in Food and feed (CODEX STAN 193-
1995) 
 
5.    Heavy Metals  
 
Heavy metal contaminants, if present, shall co mply with the limits specified in Table 2. 
 
Table2—HeavymetalcontaminantlimitsinPurpletea 
   
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 SL No.  Paramete r Limit Test method  
i) Arsenic ( As),ppm, max. 0.1 AOAC 999.10  
iv) Cadmium (Cd), ppm, max. 0.1 AOAC 942.17  
 Lead (Pb), ppm Max 0.1 AOAC 942.17  
 
 
Figures in table above set as minimum default subjec t to endorsement by CODEX Alimentarius Commission  
 
5.    Iron Fillings 
 
Iron fillings, if present, shall comply wi th the limits specif ied in Table 3. 
 
Table3—Iron fillingslimitsin Purpletea 
 
SL No.  Parameter  Limit  Test method  
1. Iron filings,ppmmax. 50 KS 2160 
 
 
 
6.    HYGIENE  
 
 
 
6.1It is recommended that the products covered by the provisions of this standard be prepared and handled in 
accordance with the appropriate sections of KS EAS 39,  and other relevant Kenya standards and regulations. The 
products should comply with any microbiological cr iteria established in accordance with CAC/GL 21.  
 
6. 2Herbaland fruit infusions productsshallcomplywithmicrobiologicalrequirementsinTable4 
 
 
Table3— Microbiological limits for Purpletea 
 
 
SL No  Type of micro‐organism   Limits Test method 
(i)  Yeasts cfu/ g, max  103KS ISO 21527‐2 
  Mouldscfu/  g, max  104KS ISO 21527‐1 
(ii)  Pathogenic Staphylococcus  
aureus cfu/ g, max Absent KS ISO 6888‐1 
(iii)  E. Coli, cfu/ g, max  Absent KS ISO 7251 
(iv)  Salmonella  spp, cfu/ 25 g, max  Absent KS ISO 6579 
 
 
 
 
7      Environment  
 
Purpletea shallbeproduced,processedandhandledunderconditionscomplyingwiththestipulationsofthe 
EnvironmentalManagementand Co-ordinationAct(EMCA) , No.8 of1999ofthe LawsofKenya,on environmental 
managementand complying with cleaner productiontechnologicalpractices.   
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8        Packaging 
 
The tea shall be packed in suitable, clean and dry container s, made of material, which does not change the tea 
quality (preserves tea quality) 
 
8.1 Purpleteashallbepackagedinfoodgradematerialthatensu resproductsafetyandintegri ty,and complying with 
KS 1927. 
 
8.2     The fill of the package shallcomply with the Wei ghts and Measures Act, Cap. 513 of the Lawsof Kenya. 
 
8.3 Thedisposalofusedpackageandcondemnedpurpleteashallbecarriedoutincompliancewiththe 
EnvironmentalManagementand CoordinationAct(EMCA),W asteRegulations,2006 oftheLawsofKenyaon disposal 
of solid and liquidwastes. 
 
 
9 Labelling 
 
9.1     In addition to the provisions of the General Standard for the Labelling of Prepackaged Foods; KS EAS 38, the 
following specific provisions apply:  
 
i) product name as “purpleTea’’; 
ii) name, address and physical location of t he manufacturer/ packer/ importer/ exporter; 
iii) date of manufacture; 
iv) expiry date; 
v) method of manufacturing; 
vi) the declaration “Food for Human Consumption”; 
vii) storage instructions as ‘’Store in a Cool Dry Place, Away from Contaminants and direct sunlight’’; 
viii) lot/batch/code number; 
ix) net weight in g or kg; 
x) instructions on disposal of used package; and 
xi) country of origin 
 
9.2 A declaration of any inaccurate information in ma rking/labelling is prohibited and shall be punishable by 
law under the Standards Act, Cap.  496, of the Laws of Kenya. 
 
 10 Sampling 
 
Sampling of purple tea for analysis shall be carried out in compliance with KS ISO1839.  
  
  
  
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