ICS 67.140.1O  
 
 Reference number  
DRS 476 : 2021 
© RSB 2021 
  
 RWANDA 
STANDARD  DRS  
476 
 
First edition  
2021-XX-XX 
 
Flavoured green tea  — Specification  
   
DRS 476 : 2021  
©RSB 2021 - All rights reserved                  ii 
 In order to match with technological development and to keep continuous progress in industries, 
standards are subject to periodic review. Users shall ascertain that they are in possession of the latest 
edition  
 
 
 
 
 
 
 
 
© RSB 2021  
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized 
in any form or by any means, electronic or mechanical, including photocopying and microfilm, without 
prior written permission from R SB. 
Requests for permission to reprodu ce this document should be addressed to : 
Rwanda Standards  Board  
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KK 15 Rd, 49  
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Toll Free: 3250  
E-mail: info@rsb.gov.rw  
Website: www.rsb.gov.rw  
ePortal: www.portal.rsb.gov.rw  DRS 476 : 2021  
iii                ©RSB 2021 - All rights reserved  
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ...................  iv 
1 Scope  ................................ ................................ ................................ ................................ .............  1 
2 Normative references  ................................ ................................ ................................ ...................  1 
3 Terms and definitions  ................................ ................................ ................................ ..................  2 
4 Requirements  ................................ ................................ ................................ ................................  3 
4.1 Ingredients  ................................ ................................ ................................ ................................ .... 3 
4.2 General requir ements  ................................ ................................ ................................ ..................  3 
4.3 Specific requirements  ................................ ................................ ................................ ..................  3 
5 Hygiene  ................................ ................................ ................................ ................................ ..........  4 
6 Contaminants  ................................ ................................ ................................ ................................  4 
6.1 Iron filings  ................................ ................................ ................................ ................................ ..... 4 
6.2 Pesticide residues  ................................ ................................ ................................ ........................  4 
7 Packaging  ................................ ................................ ................................ ................................ ...... 5 
8 Labelling  ................................ ................................ ................................ ................................ ........  5 
9 Sampling  ................................ ................................ ................................ ................................ ....... 5 
Annex  A (normative)  Determination of iron filings  ................................ ................................ ...............  6 
A.1 A.1 Apparatus  ................................ ................................ ................................ ...............................  6 
A.2 A.2 Procedure  ................................ ................................ ................................ ...............................  6 
A.3 A.3 Calculation  ................................ ................................ ................................ ..............................  6 
 DRS 476 : 2021  
©RSB 2021 - All rights reserved                  iv 
 Foreword  
Rwanda Standard s are prepared  by Technical Committees and approved by R wanda Standards Board (RSB) 
Board  of Directors in  accordance with the procedures of RSB, in compliance with Annex 3 of the WTO/TBT 
agreement on the preparation, adoption and application of standards.  
The main task of technical committees is to prepare national standards.  Final Draft Rwanda S tandards adopted 
by Technical committ ees are ratified  by me mbers of RSB Board of Director s for publication and gazettment  as 
Rwanda Standards.  
DRS 476  was prepared by Technical C ommittee RSB/TC 002 on Tea and Derived Products . 
In the preparation of this standard, the following documents  
ISO 11287: 2011, Green tea — Definition and basic requirements  
Committee membership  
The following organizations were represented on the Technical  Committee on  Tea and Derived Products  
(RSB/TC 002) in the preparation of this standard.  
Mulindi Factory Company Ltd  
Mushubi Tea Company Ltd  
National Agricultural Export Development Board (NAEB)  
National Industrial Research and Development Agency ( NIRDA ) 
Nyabihu TVET School  
Rwanda  Agriculture and Animal Resources Development Board  (RAB)  
Rwanda Food and Drug Authority (RFDA)  
Shagasha Tea Company Ltd  
Sorwathe Ltd  
Rwanda  Standards Board ( RSB) – Secretariat  
  DRS 476 : 2021  
1                ©RSB 2021 - All rights reserved  
 Flavoured g reen tea — Specification  
1 Scope  
This Draft Rwanda  Standard specifies requirements, sampling and test methods for flavoured  green tea  of 
Camellia sinensis (Linneaus ) O. Kuntze . 
This standard  is not applicable to green tea  which is not flavoured or green tea subject to further processing 
such as decaffeination . 
2 Normative references  
The following documents are referred to in the text in such a way that some or all of their content constitutes 
requirements 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.  
ISO 1575 , Tea — Determination of total ash  
RS CAC/RCP 1 , General principles of food hygiene  
RS EAS 38, Labelling of pre-packaged foods  — General requirements  
RS EAS 921, Green tea — Specification  
RS ISO 14502 -1, Determination of substances characteristic of green an d black tea — Part 1: Content of total 
polyphenols in tea – Colorimetric method using Folin — Ciocalteu reagent  
RS ISO 14502 -2, Determination of substances characteristic of green and black tea — Part 2: Content of 
catechins in green tea — Method using high -performance liquid chromatography  
RS ISO 15598, Tea — Determination of crude fibre content  
RS ISO 15 72, Tea — Preparation of ground sample of known dry matter content  
RS ISO 1573 , Tea — Determination of loss in mass at 103 degrees C  
RS ISO 1576 , Tea — Determination of water -soluble ash and water -insoluble ash  
RS ISO 1577 , Tea — Determination of acid -insoluble ash  
RS ISO 1578 , Tea — Determination of alkalinity of water -soluble ash   
©RSB 2021 - All rights reserved                  2 
 RS ISO 16649 -2, Microbiology of food and animal feeding stuffs — Horizontal method for the enumeration of 
beta-glucuronidase -positive Escherichia coli — Part 2: Colony -count technique at 44 °C using 5 -bromo -4-
chloro -3-indolyl  beta-D-glucuronide  
RS ISO 1839 , Tea — Sampling  
RS 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 than or equal to 0 ,95 
RS ISO 3103, Tea — Preparation of liquor for use in sensory tests  
RS ISO 6579 -1, Microbiology of the food chain — Horizontal method for the detection, enumeration and 
serotyping of Salmonella — Part 1: Detection of Salmonella spp. — Amendment 1: Broader range of incubation 
temperatures, am endment to the status of Annex D, and correction of the composition of MSRV and SC  
RS ISO 9768 , Tea — Determination of water extract  
3 Terms and definitions  
For the purposes of this document, the following terms and definitions apply.  
3.1  
green tea  
tea deri ved solely and exclusively  from tender leaves, buds and shoots of varieties of the species Camellia 
sinensis (Linnaeus)  O. Kuntze known , and produced by acceptable processes, notably enzyme inactivation  by 
roasting or steam ing, rolling , drying, sorting and  grading  to be suitable for making tea for consumption as a 
beverage  
3.2 
flavoured green tea  
green tea to which flavorings and/or food  ingredients with flavoring properties are added in order to  lend a 
specific flavor  
3.3  
foreign matter  
organic or inorganic  material other than tea leaf 
3.3 
adulterant  
any material intentionally added that changes the original composition and compromises the quality and safety  
of green tea DRS 476 : 2021  
3                ©RSB 2021 - All rights reserved  
 3.4 
food grade packaging material  
packaging material, made of substances which are safe and suitable for their intended use and which will not 
impart any toxic substance or undesirable odour or flavour to the product  
4 Requirements  
4.1 Ingredients  
Flavoured green  tea shall:  
a) have green  tea complying with RS EAS 921 as the basic ingredient ; and 
b) contain flavouring agents complying with relevant standards  and should be used in accordance with 
CAC/GL 66.  
4.2 General r equirements  
4.2.1 Flavoured g reen tea shall : 
a) have characteristic flavour of the flavouring agent used ; 
b) be free from taint;  
c) be free from foreign matter;  
d) be free from insects and moulds;  
e) be free from adulterants; and  
f) be free from added coloring  matter  other than those constituent of the flavoring agent . 
4.2.2 Liquor f or sensory assessment shall be prepared in accordance with RS ISO 3103 . 
4.3 Specific  requirements  
Flavoured g reen tea shall comply with the specific requirements given  in Table 1 when tested in accordance 
with the test methods specified therein.  
Table 1 — Specific requirements for flavoured green tea  
S/N Characteristic  Requirement  Test method  
i.  Moisture content, %, (m/m), max.  7 RS ISO 1573   
©RSB 2021 - All rights reserved                  4 
 ii.  Water extract, % (m/m) , min. 32 RS ISO 9768  
iii.  Total ash, %, (m/m)  4 – 8 ISO 1575  
iv.  Water -soluble ash  of total ash, % , 
(m/m) , min. 45 RS ISO 1576  
v.  Alkalinity of water -soluble ash (as 
KOH), % , (m/m)  1.0 – 3.0a RS ISO 1578  
vi.  Acid-insoluble ash, % , (m/m) , max. 1.0 RS ISO 1577  
vii.  Crude fibre, %, (m/m), max.  16.5 RS ISO 15598  
viii.  Total catechins, % , (m/m) , min. 7 RS ISO 14502 -2 
ix.  Total polyphenols, % , (m/m) , min. 11 RS ISO 14502 -1 
NOTE 1 The minimum ratio of total catechins to total polyphenols is 0.5.  
NOTE 2 Except for water extract, the requirements shall be determined using a ground sample 
prepared in accordance with RS ISO 1572. 
a When the alkalinity of water -soluble ash is expressed in terms of millimoles of KOH per 100 g of ground 
sample, the limits shall be 17.8 – 53.6. 
5 Hygiene  
5.1 Flavoured  green tea shall be processed and handled in a hygienic manner in accordance with RS 
CAC /RCP 1 . 
5.2 Flavoured  green tea shall not exceed  microbiological limits given in Table 2 when tested in accordance 
with the test methods specified therein.  
Table 2 — Microbiological limits for flavoured  green tea  
S/N Microorganism  Maximum limit  Test method  
i.  Yeasts and m oulds , cfu/ g 104 RS ISO 21527 -2 
ii.  Escherichia  coli, cfu/g Absent  RS ISO 16649 -2 
iii.  Salmonella  spp per 25 g  Absent  RS ISO 6579 -1 
6 Contaminants  
6.1 Iron filings  
When tested in accordance with Annex A , the amount of iron filings in flavoured green tea shall not exceed 1 50 
mg/kg . 
6.2 Pesticide residues  
Flavoured g reen tea shall comply with the updated maximum pesticide residue limits established by the Codex 
Alimentarius Commission.  DRS 476 : 2021  
5                ©RSB 2021 - All rights reserved  
 7 Packaging  
Flavoured g reen tea shall be packaged in closed, clean and dry  food grade packaging materials which do not 
compromise the quality and safety of the product.  
8 Labelling  
In addition to the requirements specified in RS EAS 38, each package of the  flavoured  green tea shall be legibly 
and indelibly labelled with the following:  
a) name of the product as “ Flavoured  green  tea’’;  eg “Ginger flavoured  green tea” ; 
b) name and physical address of the manufacturer/packer/importer/exporter;  
c) date of manufacture;  
d) best before;  
e) batch/lot number;  
f) net weight in grams or kilograms;  
g) country of origin; and  
h) instructions for use and storage.  
9 Sampling  
Sampling for flavoured green tea shall be done in accordance with RS ISO 1839.  
 
 
  
©RSB 2021 - All rights reserved                  6 
 Annex  A 
(normative)  
 
Determination of iron filings  
A.1 A.1 Apparatus  
A.1.1  Magnet (at least 4  000 gauss)  
A.1.2  Polythene sheet  
A.1.3  Petri dish  
A.2 A.2 Procedure  
A.2.1  A known amount of (25 g) tea is spread evenly on petri dish. 
A.2.2  A powerful magnet wrapped in polythene sheet is run over the sample repeatedly till  no more iron filings 
cling to the magnet . 
A.2.3  Collect the iron filings in a clean, dry and previously weighed petri  dish. 
A.2.4  Note down and express the mass of iron filings as mg/kg . 
A.3 A.3 Calculation  
210001
MM
filings Iron

 
where  
M1 is the m ass, in g rams , of iron filings, and  
M2 is the mass, in g rams , of sample taken for the test. 
 DRS 476 : 2021  
7                ©RSB 2021 - All rights reserved  
 Bibliography  
1) ISO 11287: 2011, Green tea — Definition and basic requirements  
 DRS 476 : 2021  
Price based on 6 pages  
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