ICS 67.080.01  
 
Reference number
DRS 302:2020
© RSB 2020
  
 RWANDA 
STANDARD  DRS
302
Second edition
2020 -mm-dd
(Reaffirmed yyyy-mm-dd)
Processed mushrooms  — Specification  
   
DRS 302: 2020  
©RSB 202 0 - 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 2020  
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  
P.O Box 7099 Kigali -Rwanda  
KK 15 Rd, 49  
Tel. +250 788303492  
Toll Free: 3250  
E-mail: info@rsb.gov.rw  
Website: www.rsb.gov.rw  
ePortal: www.portal.rsb.gov.rw   DRS 302: 2020  
iii                ©RSB 2020  - All rights reserved  
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ...................... iv 
1 Scope  ................................ ................................ ................................ ................................ ................ 1 
2 Normative references  ................................ ................................ ................................ ....................... 1 
3 Terms and definitions  ................................ ................................ ................................ ...................... 2 
4 General requirements ................................ ................................ ................................ ....................... 6 
5 Specific requirements  ................................ ................................ ................................ ...................... 6 
5.1 Dried mushrooms  ................................ ................................ ................................ ............................. 6 
5.2 Mushroom grits  and mushroom powder  ................................ ................................ ......................... 7 
5.3 Pickled and fermented mushrooms ................................ ................................ ................................ .7 
5.4 Quick frozen mushrooms and mushrooms in olive oil and other vegetable oil  ............................ 8 
5.5 Salted and sterilized mushrooms  ................................ ................................ ................................ ....8 
5.6 Mushroom extract, mushroom concentrated and dried mushroom concentrate  .......................... 9 
6 Contaminants  ................................ ................................ ................................ ................................ ...9 
7 Hygiene  ................................ ................................ ................................ ................................ ...........  10 
8 Sampling  ................................ ................................ ................................ ................................ .........  10 
9 Packaging  ................................ ................................ ................................ ................................ ....... 10 
10 Labelling  ................................ ................................ ................................ ................................ .........  10 
Annex  A (normative)  List of edible mushroom species  ................................ ................................ ...........  12 
Annex  B (normative)  Determination of organic impurities, crushed and damaged mushrooms  ...........  13 
B.1 Principle  ................................ ................................ ................................ ................................ ..........  13 
B.2 Equipments  ................................ ................................ ................................ ................................ ..... 13 
B.3 Preparation of the test sample  ................................ ................................ ................................ ....... 13 
B.4 Procedure  ................................ ................................ ................................ ................................ ....... 13 
B.4.1  General ................................ ................................ ................................ ................................ ............  13 
B.4.2  Determination of organic impurities  ................................ ................................ ..............................  14 
B.4.3  Determination of damaged and insect damaged mushroom  ................................ .......................  14 
B.4.4  Determination of crushed mushroom (for  dried mushroom)  ................................ .......................  14 
B.5 Calculations  ................................ ................................ ................................ ................................ .... 14 
B.5.1  Organic Impurities (OI)  ................................ ................................ ................................ ...................  14 
B.5.2  Damaged Mushroom (DM)  ................................ ................................ ................................ .............  14 
B.5.3  Insect damaged mushroom (IDM)  ................................ ................................ ................................ .. 15 
B.5.4  Crushed Mushroom (CM)  ................................ ................................ ................................ ...............  15 
 DRS 302: 2020  
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 Foreword   
Rwanda Standard s are prepared  by Technical Committees and approved by Rwanda 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 ratifie d by me mbers of RSB Board of Director s for publication and 
gazettment as Rwanda Standards.  
DRS 302 was prepared by Technical Committee RSB/TC 038, Processed fruits and vegetables . 
This second edition cancels and replaces the first edition (RS  302-1:2015), which has been technically 
revised.  
Committee membership  
The following organizations were represented on the Technical Committee on Processed fruits and 
vegetables  (RSB/TC 038) in the preparation of this standard.  
Rwanda  Standards Board  (RSB) – Secretariat  
 DRS 302:2020  
1                ©RSB 2020  - All rights reserved  
 Processed mushrooms — Specification  
1 Scope   
This Draft Rwanda Standard prescribes requirements , sampling  and test methods for processed mushrooms 
of edible species.  
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.  
AOAC 967.19, water in dried vegetables  
AOAC 967.24, Filth in mushrooms  
AOAC 971.27, Sodium chloride in canned vegetables. Meth od I 
ISO 1026, Fruit and vegetable products -- Determination of dry matter content by drying under reduced  
pressure and of water content by azeotropic distillation  
ISO 17239, Fruits, vegetables and derived products -- Determination of arsenic content -- Method using  
hydride generation atomic absorption spectrometry  
ISO 6633, Fruits, vegetables and derived products -- Determination of lead content -- Flameless atomic 
absorption spectrometric method  
ISO 762 , Fruit and vegetable products -- Determination of mineral impurities content  
ISO 763, Fruit and vegetable products — Determination of ash insoluble in hydrochloric acid  
ISO 9526, Fruits, vegetables and derived products -- Determination of iron content by flame atomic absorption  
spectrometry  
ISO/TS 6579 -2, Microbiology of food and animal feed -- Horizontal method for the detection, enumeration and  
serotyping of Salmonella -- Part 2: Enumeration by a miniaturized most probable number technique.  
RS Codex Stan 192, General standard for food additives  
RS EAS 82 , Milled cereal products — Methods of test  
RS ISO 16050, Foodstuffs -- Determination of aflatoxin B1, and the total content of aflatoxins B1, B2, G1 and  
G2 in cereals, nuts and derived products -- High-performance liquid chromatographic method   
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 RS ISO 16649 -1, Microbiology of food and animal feeding stuffs -- Horizontal method for the enumeration of  
beta-glucuronidase -positive Escherichia coli -- Part 1: Colony -count technique at 44 degrees C using  
membranes and 5 -bromo -4-chloro -3-indolyl beta -D-glucuronide  
RS ISO 21527 -1, Microbiology of food and animal feeding stuffs -- Horizontal method for the enumeration of  
yeasts and moulds -- Part 1: Colony count technique in products with water activity greater than 0,95  
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 6888 -2, Microbiology of food and animal feeding stuffs -- Horizontal method fo r the enumeration of  
coagulase -positive staphylococci (Staphylococcus aureus and other species) -- Part 2: Technique using rabbit  
plasma fibrinogen agar medium  
RS ISO 874, Fruits and vegetables — Sampling.  
3 Terms and definitions  
For the purposes of this standard, the follow ing terms and definitions apply. 
3.1 
edible mushrooms  
fruit bodies of the fungi plant group suitable for use as human food  
3.2 
processed mushrooms  
dried edible mushrooms (including freeze -dried mushrooms, mushroom grits, mushroom powder), pickled  
mushroom, salted mushroom, fermented mushrooms, mushrooms in vegetable oils, quick frozen mushrooms,  
sterilized mushrooms, mushroom extracts, mushroom concentrate and dried mushroom concentrate  
3.3 
dried mushrooms  
mushrooms obtained by drying or fr eeze drying of edible mushrooms of one species, whether whole or sliced  
3.4 
mushroom grits  
coarsely ground dried edible mushrooms of one species  DRS 302:2020  
3                ©RSB 2020  - All rights reserved  
 3.5 
mushroom powder  
dried edible mushroom of one species ground finely  
3.6 
pickled mushroom  
fresh or preserved edible mushroom of one or more species appropriately prepared after cleaning, washing  
and blanching, soaked in vinegar and with or without the addition of salt, spices, sugars, vegetable  oils, acetic,  
lactic, citric or ascorbic acid, and then pasteurized  in hermetically sealed container  
3.7 
salted mushroom  
fresh edible mushrooms of one species, either whole or sliced, preserved in brine after cleaning, wa shing and  
blanching  
3.8 
fermented mushrooms  
fresh edible mushrooms of one species preserved by salt and by lactic acid fermentation  
3.9 
quick frozen mushroom  
fresh edible mushrooms of one species which, after cleaning, washing and blanching are subjected to a 
freezing process  
3.10 
mushroom extract  
products concentrated from fresh edible mushroom juice or from dried mushroom water of edible mushroom  
of one or more species with the addition of salt and which is concentrated to 7 % salt less extract  
3.11 
mushroom concentrate  
product concentrated from fresh edible mushroom juice or from dried mushroom water of  edible mushroom of  
one or more species with the addition of salt which is concentrated to 24 % of salt less extract   
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 3.12 
dried mushroom concentrated  
dried product obtained from mushroom extract or mushroom concentrate  
3.13 
sterilized mushroom  
edible mushr oom, fresh, salted or frozen, of one or more species, whole or sliced, packed in air tight  
containers in water and salt, and heat treated to a degree guaranteeing the resistance of the produc t to 
spoilage  
3.14 
mushroom in olive oil and other vegetable oils  
edible mushrooms either fresh or previously salted, of one species, whole or sliced, packed in airti ght 
containers in olive oil or other vegetable oil and heat treated to a degree guaranteeing the resista nce of the  
product to spoilage  
3.15 
whole dried mus hroom  
product obtained from whole cleaned and dried edible mushrooms. Their stalks may be shortened  
3.16 
whole caps without stems  
product obtained from whole caps with their stems having been removed  
3.17 
cut dried mushrooms  
mushrooms obtained from whole edible mushrooms sliced and dried; the thickness of the individual slices  
being 1 mm - 4 mm  
3.18 
damaged mushroom  
mushroom with more than quarter of the cap missing  
3.19 
crushed mushroom  
parts of mushroom passing through sieve having 5 mm x 5 mm mesh for dried mushroom  DRS 302:2020  
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 3.20 
carbonized mushrooms  
whole or dried mushrooms with traces of carbonization on their surface  
3.21 
insect damaged mushrooms  
mushroom that have holes caused by maggots and other insects  
3.22 
seriously maggot damaged mushrooms  
mushrooms hav ing four or more holes caused by maggots  
3.23 
fallen off stalks  
stalks separated from the caps  
3.24 
organic impurities of vegetable origin  
admixture of other edible mushrooms, parts of plants such as leaves and other tree stalks  
3.25 
Filth  
Organic impuriti es of animal origin  
3.26 
inorganic impurities  
stones, glass, pieces of soil and other mineral matter  
3.27 
spoiled mushrooms  
mushrooms which are brownish or rotten as a result of attack by micro -organisms and/or mould.  
 
  
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 4 General requirements  
4.1 All products falling under the scope of this standard shall belong to the edible species specified in 
Annex A.  
4.2 All mushrooms raw material shall, in all cases, be free from poisonous mushrooms and other toxic 
ingredients; and shall not be a mixture of more than one species.  
4.3 All mushrooms that are to be harvested, marketed or preserved or to be used in the preparation of 
mushroom products shall be carefully examined by qualified person to determine whether there are any  
inedible mushrooms amongst them.  
4.4 Raw materials: Only fresh edible mushrooms which have been treated or processed before  
deterioration sets in shall be used in the preparation of processed mushrooms. Both the raw material  and 
preserved mushroom shall be healthy clean, undamaged, free as practicable of maggots damage and shall  
process the flavour and taste characteristic to the species . 
4.5 Mushroom products may contain, but not limited to, salt (sodium chloride), vinegar, spices and herbs , 
sugars, refined edible vegetable oil, butter, mil k, milk powder, cream water and wine.  
4.6 Styles : Processed mushrooms may be presented in various styles, e.g whole with stalks, whole caps  
(buttons) without stalks, slices, pieces and stalks, grits, powder or concentrate.  
4.7 Other styles : Any other prese ntation of the product shall be permitted provided that the product is  
sufficiently distinctive from other forms of presentations described and meet the requirements of th is standard  
4.8 Composition: Except in the case processed mushrooms consisting entire ly of caps or where the 
addition of stalks is stated on the label, the number of stalks shall not exceed the number of caps.  
5 Specific requirements  
5.1 Dried mushrooms  
5.1.1  Dried mushrooms shall have colour odour, texture and flavour characteristic to the spec ies 
5.1.2  They shall be clean and comply with the requirement specified in Table 1.  
Table 1 — Physical and chemical requirements for dried mushrooms  
Type of dried 
mushroom  Dried (other than 
freeze dried)  Freeze dried  Dried shiitake (other 
than freeze dried)  Method of test  
Moisture % m/m, max  12 6 13 ISO 1026  
Acid insoluble ash,% 
m/m, max  2 2 2 ISO 763  
Organic impurities of 
vegetable origin,% 
m/m, max  0.02 0.02 1 Annex B  
Filth (impurities of 1 1 1 AOAC 967.24  DRS 302:2020  
7                ©RSB 2020  - All rights reserved  
 animal origin) ,% m/m, 
max 
Crushed mushroom 
,% m/m, max  6 6 6 Annex B  
Damaged mushroom 
,% m/m, max  20 20 20 Annex B  
Mineral impurities ,% 
m/m, max  2 2 2 ISO 762  
Insect damaged 
mushroom % m/m, 
max 1 1 1 Annex B  
5.2 Mushroom grits and mushroom powder  
5.2.1  Particle size : Not less than 90 % shall pass through a 600 -µm sieve for fine flour and not less than 90 
% shall pass through a 1200 -µm sieve for mushroom grit. Testing for particle size shall be done in accordance 
with RS EAS 82.  
5.2.2  The chemical requirements for mushroom grits  and mushroom powder shall be as given in Table 2.  
Table 2 — Chemical requirements for mushroom grits and mushroom powder  
Parameter  Requirements  Method of test  
Moisture % m/m, max.  12 ISO 1026  
Acid insoluble ash,% m/m, max  2 ISO 763  
5.3 Pickled and fermented mushrooms  
The chemical and physical requirements for pickled and fermented mushrooms shall be as given in Tabl e 3. 
Table 3 — Chemical and physical requirements for pickled and fermented mushrooms  
Parameter  Pickled mushroom  Fermented mushrooms  Method of test  
Salt ( sodium chloride ) % 
m/m  ≤ 2.5  3-6 AOAC 971.27  
Sugar % m/m, max  2.5 - AOAC 998.18  
Acid insoluble ash % m/m, 
max  0.1 0.2 ISO 763  
Organic impurities of 
vegetable origin % m/m, 
max  0.02 0.1 Annex B  
Filth, %, max  1 1 AOAC 967.24  
Damaged mushroom, %, 
max  20 20 Annex B  
Mineral impurities , %, max  2 2 ISO 762  
Insect damaged mushroom 
% m/m, max  1 4 Annex B   
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 5.3.2  The permitted ingredients in the case of pickled mushrooms are salt as sodium chloride, sugars and  
vinegar (as acetic acid). Vinegar shall be used in accordance with RS Codex Stan 192.  
5.3.3  The permitted ingredients in the case of fermented mushroom are salt as sodium chloride and lactic  
acid occurring naturally into the product as a result of fermentation and it shall n ot to exceed 1 % m/m.  
5.4 Quick frozen mushrooms and mushrooms in olive oil and other vegetable oil  
5.4.1  The chemical and physical requirements for mushrooms in olive oil and other vegetable oils shall be  
as given in Table 4.  
Table 4 — Chemical and physical r equirements for quick frozen mushrooms and mushrooms in olive  
oil and other vegetable oil  
Parameter  Quick frozen  mushroom in olive oil and 
other vegetable oils  Method of test  
Salt ( sodium chloride ) % 
m/m, max  ≤ 2.5  1 AOAC 971.27  
Acid insoluble ash % m/m, 
max  0.2 0.1 ISO 763  
Organic impurities of 
vegetable origin % m/m,  0.02 0.02 Annex B  
Filth, %, max  1 1 AOAC 967.24  
Damaged mushroom, %, 
max  20 20 Annex B  
Mineral impurities , %, max  2 2 ISO 762  
Insect damaged mushroom 
% m/m, max  2 2 Annex B  
5.5 Salted and sterilized mushrooms  
5.5.1  The chemical and physical requirements for salted and sterilized mushrooms shall be as given in 
Table 5.  
Table 5 — Chemical and Physical requirements for salted and sterilized mushrooms  
Parameter  Salted mushrooms  Sterilized mushrooms  Method of test  
Salt ( sodium chloride ) % 
m/m  15 - 18 ≤ 2 AOAC 971.27  
Acid insoluble ash % m/m, 
max  0.3 0.2 ISO 763  
Organic impurities of 
vegetable origin % m/m, 
max  0.03 0.02 Annex B  
Maggot damaged 
mushroom % m/m, max  1 1 
Filth, %, max  1 1 AOAC 967.24  
Damaged mushroom, %, 20 20 Annex B  DRS 302:2020  
9                ©RSB 2020  - All rights reserved  
 max  
5.5.2  The only permitted ingredient for both salted and sterilized mushrooms is salt as sodium chloride.  
5.6 Mushroom extract, mushroom concentrated and dried mushroom concentrate  
5.6.1  The chemical and physical requirements for mushroom extract, mushroom concentrate and dried  
mushroom concentrated shall be as given in Table 6.  
Table 6 — Chemical and Physical requirements for mushroom extract, mushroom concentrate and 
dried mushroom concentra te 
Parameter  Mushroom extract and 
mushroom concentrate  Dried mushroom 
concentrate  Method of test  
Salt ( sodium chloride ) % 
m/m, max  20 5 AOAC 971.27  
Acid insoluble ash % m/m, 
max  1 1 ISO 763  
Organic impurities of 
vegetable origin % m/m,  Absent  Absent  Annex B  
Filth  1 1 AOAC 967.24  
Moisture content % m/m, 
max  - 9 ISO 1026  
5.6.2  The only permitted ingredient in mushroom extract, mushroom concentrate and dried mushroom  
concentrate is salt as sodium chloride.  
6 Contaminants  
6.1 Processed mushrooms shall comply with those maximum limits for pesticide residues as specified by  
codex alimentalius.  
6.2 Processed mushroom shall comply with maximum limits for heavy metals given in Table 6.  
Table 6 — Maximum limits for heavy metals  
Metal  Limits  Method of test  
Arsenic , mg/kg, max  0.2 ISO 17239  
Lead mg/kg, max  0.2 ISO 6633  
Iron mg/kg, max  9 ISO 9526  
6.3 Processed mushroom shall not exceed the limit on aflatoxin as specified in Table 7.  
Table 7 — Maximum limits for Aflatoxin  
Aflatoxin  Limits  Method of test  
B1, µg/kg  5 RS ISO 16050   
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 Total aflatoxin µg/kg  10 
7 Hygiene  
7.1 Processed mushroom shall handled in accordance with the provisions provided in RS CAC/RCP 1.  
7.2 The product shall be free from parasites which may represent a hazard to health and shall also not  
contain any substance originating from microorganisms in amounts which may represent a hazard to hea lth. 
7.3 Processed mushrooms shall comply with microbiological requirements as set in Table 7.  
Table 7 — Microbiological limits  
Metal  Limits  Metho d of test  
Total plate count, cfu/g max  103 RS ISO 4833  
E. Coli,  absent  ISO 16649 -1 
Staphylococcus aureus, cfu/25g,Max   102 RS ISO 6888 -2 
Salmonella, cfu/25g, max  absent  RS ISO/TS 6579 -2 
Mould, max, cfu/g  103 RS ISO 21527 -1/RSISO 21527 -2 
8 Sampling  
Sampling of processed mushroom shall be done in accordance with RS ISO 874.  
9 Packaging  
Processed mushroom shall be packaged in such a way as to protect it properly against any damage or  
expose it such that it can easily be attacked by pests or other kind of infestation or moisture ingress. The  
packaging material should preferably allow the consumer to view the product. The packages shall be f ree from  
any foreign matter, objectionable smell and shall be of food grade.  
10 Labelling  
10.1 In addition to the requi rements in RS EAS 38, processed mushrooms shall be legibly and indelibly  
marked on the label with the following information:  
a) name of the product as “ as defined in Clause 3”, and  
b) species of the processed mushroom  
10.2 The common and scientific name of the species of fungus used, but the terms "fungus" and "fungi" may 
be replaced by terms which have customarily been used to describe the genus or species concerned in the 
country in which the product is intended to be sold, e.g. "mushroom" or "mushrooms" for t he genus Agaricus.  
10.3 In the case of processed mushrooms consisting of more than one species, such fact as “mixed” shall 
form part of the designation.  DRS 302:2020  
11                ©RSB 2020  - All rights reserved  
 a) style of presentation,  
b) list of ingredients in descending order of proportion except for those products exclusively made from 
mushroom,  
c) name and physical and postal address of producer/packer or distributor,  
d) country of origin,  
e) net weight/or Drained weight where applicable,  
f) manufacturing date,  
g) storage instruction, and  
h) expiry date.   
©RSB 202 0 - All rights reserved                  12 
 Annex  A 
(normative)  
 
List of edible  mushroom species  
a) Agaricus bisporus  
b) Auricularia polytricha or Auricularia auricula -judae  
c) Flammulina velutipes  
d) Hypsizygus tessulatus  
e) Lentinus edodes.  
f) Pleurotus cornucopiae  
g) Pleurotus eryngii  
h) Pleurotus ostreatus  
i) Rhizopus oligosporus  
j) Sparassis crispa  
k) Tremella fuciformis  
l) Tuber aestivum  
m) Tuber magnatum  
n) Tuber melanosporum  
o) T.melanosporum x T.magnatum  
p) Terfezia sp.  
q) Ustilago maydis  
r) Volvariella volvacea  
s) Fusarium venenatum   DRS 302:2020  
13                ©RSB 2020  - All rights reserved  
 Annex  B 
(normative)  
 
Determination of organic impurities, crushed and damaged mushrooms  
B.1 Principle  
Impurities, crushed mushroom, damaged mushroom, insect damaged mushrooms and maggot damaged  
mushrooms are determined by normal count under normal vision of a naked eye or by magnifying lense o f 
X10, if necessary  
B.2 Equipments  
B.2.1 Balance, capable of being r ead to the nearest 0.01 g  
B.2.2 Dishes  
B.2.3 Tweezers , scalpel  
B.2.4 Shallow container , having a surface area of at least 200 cm 2 
B.2.5 Magnifying lense of X10  
B.2.6 Set of test sieves , with long rounded apertures, comprising sieve of 5.00 mm × 5.00 mm, a receiver and a 
lid. 
B.3 Preparation of the test sample  
B.3.1  Carefully mix the laboratory sample to make it as uniform as possible, and then proceed to reduce it , if 
necessary, until a quantity of approximately 500 g is obtained.  
B.3.2  Weigh, to the nearest 1 g, the test sample so obtained and place it in the container (B.2.4).  
B.3.3  During the preparation of the test sample, note whether any particular odour foreign to that of whea t is 
detected, whether any living insects (specified in Annex B) are present or other anomalies.  
B.4 Procedure  
B.4.1  General  
If a grain exhibits several defects, it shall be classified in the category with the lowest maximum permissible  
level  
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 B.4.2  Determination of organic impurities  
Separate organic impurities (3.24) from the test sample (B.3.2), put it in a tared dish (B.2.4) and weigh it to the  
nearest 0.01 g (W1)  
B.4.3  Determination of damaged and insect damaged mushroom  
B.4.3.1  Weigh the test sample obtained in B.4.2, after removing organic impurities (W2)  
B.4.3.2  Separate damaged mushrooms (3.18) an d insect damaged mushroom (3.21) from the test 
sample  (B.4.3.1), put them in a tared dish (B.2.4) separately and weigh them to the nearest 0.01 g, W3 and 
W4 respectively)  
B.4.4  Determination of crushed mushroom (for dried mushroom)  
B.4.4.1  Fit together the 5 mm x 5 mm and the receiver, so that the sieve apertures are positioned parallel 
to each other.  
B.4.4.2  Take the test sample obtained in B.4.3.2, after removing damaged and insect damaged 
mushroom  and place it on the 5 mm x 5 mm sieve and put on the lid.  
B.4.4 .3 Shake manually for 45 s with a forwards -and-backwards motion in the direction of the apertures 
of the  sieve, keeping the sieve in a horizontal plane. The fraction that pass through to the 5 mm x 5 mm si eve 
correspond to the crushed mushroom (3.19)  
B.4.4 .4 Weigh the fractions that has passed through the 5 mm x 5 mm sieve to the nearest 0.01 g (W5)  
B.5 Calculations  
B.5.1  Organic Impurities (OI)  
OI = (W1)/ (W0)100 
Where;  
OI Organic impurities;  
W0 Test sample obtained in B.3.2;  
W0 weight of organic impurities obtained  in B.4.2.  
B.5.2  Damaged Mushroom (DM)  
DM =W3 /W2.100  DRS 302:2020  
15                ©RSB 2020  - All rights reserved  
 Where;  
DM Damaged Mushroom;  
W2 Test sample obtained in B.4.3.1;  
W3 Weight of damaged mushroom obtained in B.4.3.2.  
B.5.3  Insect damaged mushroom (IDM)  
IDM =W4 /W2.100  
Where;  
IDM Insect Damaged Mushroom;  
W2 Test sample obtained in B.4.3.1;  
W4 weight of insect damaged mushroom obtained in B.4.3.2.  
B.5.4  Crushed Mushroom (CM)  
CM =W5 /W2.100  
Where;  
CM Crushed Mushroom;  
W2 Test sample obtained in B.4.3.1;  
W5 weight of crushed mushroom passing through 5 mm x 5 mm sieve obtai ned in B.4.4.4.  
 
 
 
  
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 Bibliography  
[1] RS 302: 2016 Processed Mushrooms —Specification, First edition  DRS 302: 2020  
 
Price based on  nnn pages  
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