ICS 67.060  
 
Reference number
DRS 286: 2020
© RSB 2020
  
 RWANDA 
STANDARD  DRS
286
Second edition
2020 -mm-dd
(Reaffirmed yyyy-mm-dd)
Prevention and reduction of aflatoxin 
contamination in peanuts — Code of 
practice  
   
DRS 286: 2020  
©RSB 2020 - 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  
 
 
 
 
 
 
 
 
© RSB2020  
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 reproduce thi s document should be addressed to : 
Rwanda Standards  Board  
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E-mail: info@rsb.gov.rw  
Website: www.rsb.gov.rw  
ePortal: www.portal.rsb.gov.rw  DRS 286: 2020  
iii                ©RSB2020 - All rights reserved  
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ...................... iv 
1 Scope  ................................ ................................ ................................ ................................ ................ 1 
2 Normative references  ................................ ................................ ................................ ....................... 1 
3 Terms and definitions  ................................ ................................ ................................ ...................... 1 
4 Recommended practices  ................................ ................................ ................................ ................. 2 
4.1 General ................................ ................................ ................................ ................................ .............. 2 
4.2 Recommended practices based on Good Agricultural Practices (GAP)  ................................ .......2 
4.2.1  Pre-harvest  ................................ ................................ ................................ ................................ .......2 
4.2.2  Harvest  ................................ ................................ ................................ ................................ .............. 3 
4.2.3  Transport  ................................ ................................ ................................ ................................ .......... 4 
4.2.4  Storage ................................ ................................ ................................ ................................ .............. 5 
4.3 Good Manufacturing Practice (GMP)  ................................ ................................ ............................... 6 
4.3.1  Receiving and shelling  ................................ ................................ ................................ ..................... 6 
4.3.2  Sorting ................................ ................................ ................................ ................................ .............. 6 
4.3.3  Packaging and storage of end product  ................................ ................................ ........................... 7 
4.4 Complementary management system  ................................ ................................ ............................. 7 
Annex A (normative)  Annex title  ................................ ................................ ................................ ................. 9 
Annex  B (informative)  Which styles correspond to which element — Quick reference guide  ...............  10 
 DRS 286: 2020  
©RSB 2020 - All rights reserved                  iv 
 Foreword  
Rwanda Standard sareprepared 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 ratifie d by me mbers of RSB Board of Director s for publication and 
gazettment as Rwanda Standards.  
DRS286 was prepared by Technical Committee RSB/TC 003, Cereals, pulses, legumes and derived products . 
In the preparation of this standard, reference was made to the following standard  (s): 
1) XYZ: Title  
The assistance de rived from the above source is hereby acknowledged with thanks.  
This second/third/... edition cancels and replaces the first/second/... edition (RS  nnn-n:yyyy), [clause(s) / 
subclause(s) / table(s) / figu re(s) / annex(es)] of which [has / have] been technically revised.  
(The first/second/third/... edition (RS  nnn-n: yyyy) has been re affirmed  by the Board on dd-mm-yyyy. ) 
RSnnn consists of the following parts, under the general title Introdu ctory element — Main element : 
 Part n: Part title  
 Part [n+1]: Part title  
Part [n+2]: Part title  
Committee membership  
The following organizations were represented on the Technical Committee on Cereals, pulses, legumes and 
derived products (RSB/TC 003) in the preparation of  this standard.  
Paragraph of p articipants  
Rwanda  Standards Board (RSB) – Secretariat  DRS 286: 2020  
v                ©RSB2020 - All rights reserved  
 Introduction  
A paragraph.  DRS 286:2020  
1                ©RSB2020 - All rights reserved  
 Prevention and reduction of aflatoxin contaminatio nin peanuts — Code of 
practice  
1 Scope  
This Rwanda Standard provides general recommended practices based on Good Agriculture Practices (GAP ) 
and Good Manufacturing Practices (GMP) and complementary management system for the reduction of 
aflatoxin in groundnuts (peanuts).  
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.  
RS 184, Requirements for hazard analysis critical control points.  
RS CAC/RCP 1, Code of practic e –General principle for food hygiene  
RS 285, Groundnuts handling, transportation and storage – Code of hygienic practice  
RS 264, Warehouse and warehousing for bagged storage of cereals and pulses – Requirements.  
3 Terms and definitions  
For the purposes of t his standard, the follow ing terms and definitions apply . 
3.1 
blows(pops)  
in-shell nuts which are unusually light -weight due to extensive damage from physiological, mould, insect, or 
other causes and which can be removed, for example, by an air -separation p rocess  
3.2 
curing  
drying of in -shell groundnuts (peanuts) to a safe moisture level  
3.3 
farmer's stock groundnuts (peanuts)  
in-shell groundnuts (peanuts) as they come from the farm, after separation from the vines by hand and/o r 
mechanical means   
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 3.4  
safe water activity  
water activity of in -shell and shelled groundnuts (peanuts) that prevents growth of micro -organisms normal to 
the nut processing and storage environment  
3.5 
water activity  
measure of free moisture in a product and is the water vapour pressure of the substance divided by the 
vapour pressure of pure water at the same temperature.  
4 Recommended practices  
4.1 General  
Groundnut shall be produced, handled and processed in accordance with the provisions in RS CAC/RCP 1  
and RS 285.  
4.2 Recommended pract ices based on Good Agricultural Practices (GAP)  
4.2.1  Planting  
4.2.1.1  To be effective, pre -harvest control of aflatoxin contamination of peanuts shall take into 
consideration all the varied environmental and agronomic factors that influence pod and seed infecti on by the 
aflatoxin producing fungi, and aflatoxin production. It should be necessary to devise agricultural p ractices that 
by considering location and season of production.  
4.2.1.2  Consider developing and maintaining a crop rotation schedule to avoid plan ting the groundnut in 
a field in two consecutive years. Cereals have been found to be particularly susceptible to A. flavus/A. 
parasiticus  and they should not be used in rotation with groundnut. Crops such as potato, other vegetables, 
clover and alfalfa th at are not hosts to Aspergillus species should be used in rotation to reduce the inoculum in 
the field.  
4.2.1.3  In areas that are vulnerable to erosion, soil conservation practices shall be adopted in the 
interests ofsoil conservation.  
4.2.1.4  Utilize the results of soil tests to determine if there is a need to apply fertilizer and/or soil 
conditionersto assure adequate soil pH and plant nutrition to avoid plant stress, especially during seed 
development,which makes peanuts more susceptible to fungal infest ation.  
4.2.1.5  Seed varieties developed for resistance to seed -infecting fungi and insect pests should be 
grown.Only seed varieties recommended for use in a particular area and season of a country should be  
planted inthat particular area . As far as practic al, crop planting should be timed to avoid high temperature and 
drought stress during theperiod of pod development and maturation and so that the crop matures  at the end of 
the rainy season so thatpost -harvest field drying can be done under favourable cond itions.  
4.2.1.6 Irrigation, if feasible, is recommended to combat heat and drought stress.  DRS 286:2020  
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 4.2.1.7  Water used for irrigation and other purposes (e.g. preparation of pesticide sprays) should be 
ofsuitable quality for the intended use.  
4.2.1.8  Avoid overcrowding of plants by maintaining the recommended row and intra -plant spacing for 
thevarieties grown. Optimum plant populations shall be established bearing in mind that too high a 
populationmay lead to drought stress where rainfall maybe below the opt imum required in a growing season.  
4.2.1.9  Excessive weed growth may deplete available soil moisture. Effective weed control by use 
ofregistered herbicides, or cultivation shall be done. Care should be taken during cultivation to av oid damage 
topegs and po ds. 
4.2.1.10  Cultivation and crop protection practices that lower the incidence of soil insects, mites, 
andnematodes shall be done to help in reducing aflatoxin contamination. Insect damage and disease in fection 
inthe vicinity of the crop shall be minimize d by proper use of registered insecticides, fungicides, and 
otherappropriate practices within an integrated pest management program. Growers should consult with  
competentauthorities to determine insects and other pests that are commonly found in their regi on that might 
attackpeanuts causing them to be more susceptible to fungal infections that can lead to aflatoxin pr oduction  
4.2.2  Harvest ing 
4.2.2.1  Competent authorities shall take the lead in informing growers of the hazards associated 
withaflatoxin contaminati on of peanuts and how they may practice safe harvesting procedures to reduce the 
risk ofcontamination by fungi, microbes, and pests. Personnel to be involved in harvesting peanuts s hould be 
welltrainedin the personal hygienic and sanitary practices that sh all be implemented throughout the 
harvestingseason.  
4.2.2.2  All equipment, which is to be used for harvesting and storage of crops shall be functional, clean, 
dryand free of insects and visible fungal growth before use and re -use. A breakdown during this c ritical 
periodmay cause peanut quality losses and enhance aflatoxin formation. Keep important spare parts av ailable 
onthe farm to minimize time loss from repairs.  
4.2.2.3  Peanuts shall be harvested at full maturity, unless allowing the crop to continue to full maturity 
cansubject it to extreme heat, rainfall, and drought conditions. It is very important to harvest the  crop at 
optimummaturity, as excessive numbers of over -mature or very immature pods at harvest can be reflected in 
highlevels of aflatoxin in the product; also delayed harvest of peanuts already infected may cause 
significantincrease in aflatoxin content of the crop. A system by which the growing conditions of th e farming 
crop ismonitored (soil temperature and precipitation) may be very useful.  
4.2.2.4  Individual plants that die from attack by pests, pathogens; such as Sclerotium rolfsii or 
Fusariumspp., and diseases, e.g. rosette virus, or insects, such as termites, earwigs, and false wir eworms that 
causedamage to the pods; shall be harvested se parately as their produce is likely to contain aflatoxin.  
4.2.2.5  If peanuts have been irrigated, care should be taken to separately harvest peanuts that are 
beyondthe reach of irrigation systems to avoid mixing aflatoxin -free peanuts with those that are 
potentiallycontaminated.  
4.2.2.6  Damage to pods at the time of harvest shall be avoided as much as possible since this can lead 
torapid invasion of the pods by A. flavus/A. parasiticus. Peanuts shall be handled as gently as poss ible 
andevery effort made to minimize physical damage at all stages of harvesting and transportation procedures.   
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 4.2.2.7  After harvest, pods shall be exposed for maximum rate of drying. This may be accomplished 
byturning the vines to leave the pods uppermost where they are away from t he ground and exposed to sun 
andwind. Curing shall be completed as soon as possible to a safe water activity so as to prevent the  growth 
ofmicroorganisms, particularly moulds that produce aflatoxins. However, drying too rapidly may cause  
skinslippage and o ff-flavours in the peanut kernels. When curing by supplemental heat, excessive heat shall 
beavoided since this impairs the general quality of the peanuts, e.g. splitting of kernels after she lling. 
Closechecks of moisture content/water activity of lots of f armer’s stock peanuts shall be maintained.  
4.2.2.8  Peanuts shall be dried in such a manner that damage to the peanuts is minimized and 
moisturelevels are lower than those required to support mould growth during storage (generally less than 10 
%). Thisis ne cessary to prevent further growth of a number of fungal species in peanuts.  
4.2.2.9  Freshly harvested peanuts shall be cleaned and sorted to remove damaged nuts, pre -
shelledkernels, light pods and other foreign matter.  
4.2.3  Drying  
4.2.3.1 Immediately after harvest, determine moisture levels of the crop; where applicable, dry the crop to the 
moisture content recommended for storage of that crop.  
4.2.3.2 Peanuts should be dried in such a manner that damage  to the peanuts  is minimized and moi sture 
levels are lower than those required to support mo uld growth during storage (generally less than 10%). This is 
necessary to prevent further growth of a number of fungal species in peanuts . 
4.2.4  Transport ation  
4.2.4.1 The nuts shall be moved to a suitable storage or to the processing area for immediate processing 
assoon as possible after harvesting or drying.  
4.2.4.2 Containers (e.g. wagons, trucks) to be used for collecting and transporting the harvested 
peanutsfrom the farm to drying facilities or to stor age facilities after drying, should be clean, dry, and free of 
insects,visible fungal growth and any contaminated material before use and re -use. 
4.2.4.3 As necessary, transport containers shall be cleaned and disinfected before use and re -use and 
besuitab le for the intended cargo. Only approved fumigants or insecticides shall be used. At unloading, 
thetransport container shall be emptied of all cargo and cleaned as appropriate.  
4.2.4.4 Consignments of peanuts shall be protected from all additional moisture  by using covered or 
airtightcontainers or tarpaulins. Avoid temperature fluctuations that may cause condensation to form  on the 
peanuts,which could lead to local moisture build -up and consequent fungal growth and aflatoxin formation.  
4.2.4.5 Farmers’ stoc k peanuts shall be screened for aflatoxin contamination to more accurately 
segregatefor proper storage. Aflatoxin -free loads shall be segregated from loads with low levels of 
aflatoxincontamination, destined for subsequent processing and clean -up, and from  loads that are 
highlycontaminated.  
4.2.4 .6 Insect, bird, and rodent infestation during transportation shall be avoided by the use of insect 
androdent proof containers or insect and rodent repellent chemical treatments provided they are appr oved for 
theint ended use of the peanuts.  DRS 286:2020  
5                ©RSB2020 - All rights reserved  
 4.2.5  Storage  
4.2.5 .1 Post-harvest storage of peanuts is the phase that can contribute most to the aflatoxin problem 
inpeanuts. For aflatoxin prevention in storage, mould development of the peanuts due to condensation  or 
leaksin the war ehouse should be prevented.  
4.2.5 .2 A properly ventilated warehouse with a good roof, preferably double sidewalls and a concrete 
floorare required to prevent rewetting of peanuts. Make sure that the storage facilities include dry , well -
ventedstructures tha t provide protection from rain, drainage of ground water, protection from the entry of 
insects,rodents, and birds, and minimum temperature fluctuations. Painting warehouse roofs with whit e paint 
reducessolar heat load when compared to conventional galvaniz ed material. The double roofing concept of 
installing anew roof over a defective, existing roof with an air space in -between the two roofs, has proven 
effective incontrolling warehouse condensation.  
4.2.5 .3 Water activity, which varies with moisture conten t and temperature shall be carefully 
controlledduring storage.  
4.2.5 .4 Uniform loading of the warehouse allows excessive heat and moisture to escape and 
reducesfavourable areas for insect infestation. Stock piling of peanuts can cause heat build -up and 
moistureaccumulation with resultant mould growth and aflatoxin contamination.  
4.2.5 .5 A. flavus/A. parasiticus cannot grow or produce aflatoxins at water activities less than 0.7; 
relativehumidity shall be kept below 70 % and temperatures between 0 °C and 10 °C are optimal for 
minimizingdeterioration and fungal growth during long time storage. Storage should be done at the lo west 
temperaturepossible consistent with ambient conditions but temperatures near freezing point should b e 
avoided. Wherepossible peanuts  should be aerated by circulation of air through the storage area to maintain 
proper anduniform temperature levels throughout the storage area.  
4.2.5 .6 The aflatoxin level in peanuts coming into a storage and peanuts going out of a storage shall 
bemonitore d, using appropriate sampling and testing programs.  
4.2.5 .7 For bagged peanuts, the storage shall be done in accordance with RS 264.  
4.2.5.8 Measure of the temperature and visually check for evidence of mould growth of the stored 
peanutsshall be done at se veral fixed intervals during storage. The apparently infected portions of the peanuts 
shallbe separated from the normal peanuts and not be used for food or feed production and the sample s 
foranalysis should be sent if possible.  
4.2.5 .9 Good ‘housekeeping’ procedures shall be used to minimize levels of insects and fungi in 
storagefacilities. This should include the use of suitable traps, approved insecticides or fungicide s and 
fumigants.Care shall be taken to select only those chemicals t hat cannot  affect or cause harm to the peanuts.  
4.2.5 .10 harvesting and storage procedures implemented each season should be documented by 
makingnotes of measurements (e.g. temperature, moisture, and humidity) and any deviation or changes 
fromtraditional practices. This information may be very useful for explaining the causes of fungal growth 
andaflatoxin formation during a particular crop year and help to avoid similar mistakes in the futur e.  
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 4.3 Good Manufacturing Practice (GMP)  
4.3.1  Receiving and shelling  
4.3.1. 1 Farmers’ stock peanuts received at the shelling plant shall be inspected on arrival. The 
transportvehicle should be examined. If the vehicle is not fully enclosed, it should have a covering  such as 
tarpaulin tokeep out rain or other forms of water. The g eneral appearance of the peanuts should be observed 
during theprocess of unloading. If the peanuts are wet to the touch, they shall not be mixed with pe anuts in a 
bulkwarehouse. The vehicle which contains the peanuts should be set aside until a decision is  made for 
theirdisposal. If possible, remove a sample from each lot, separate the “loose shelled” kernels and shell 
theremainder for peanut grade observation before an acceptance decision is made.  
4.3.1.2  Specifications for the purchase of peanuts intended  for further processing shall include a 
maximumlevel for aflatoxin based in appropriate methods of analysis and a proper sampling plan.  
4.3.1.3  Special precautions shall be taken to reject peanuts showing signs of insect damage or mould 
growthbecause of th e danger of their containing aflatoxins. Aflatoxin test results shall be known before 
allowing lotsof raw peanuts to be processed. Any lot of raw peanuts with unacceptable levels of afla toxins, 
which cannotbe reduced to permitted levels by the available so rting equipment, shall not be accepted.  
4.3.1.4  The peanut processor shall satisfy himself that the supplier of shelled peanuts is able to 
controlproperly his own operations to assure that the finished product is within the maximum limit f or aflatoxin.  
4.3.1.5 All loose -shelled, damaged “Blows” and under -sized kernels shall be examined for possible 
presenceof mould. If no external mould is visible, split the kernels to disclose possible hidden mou ld growth. 
Excessivemould or presence of mould resembling A. flavus warrants a chemical test for aflatoxin or rejection 
of the lot.  
4.3.2  Sorting  
4.3.2.1  Sorting is the final step for removing defective kernels. Where Sorting belts are used, they shall 
bewell lighted, with peanuts passing through no more than one layer de ep, and operated at a speed 
whichenable hand sorters to assure effective removal of foreign material and defective kernels. Sort ing 
machinesshall be adjusted as often as practicable against standards to assure removal of all defecti ve 
kernels.Adjustment sh all be checked frequently and regularly.  
4.3.2.2  To remove mould -contaminated nuts effectively, sorting shall be performed before and 
afterblanching and roasting. Blanching used in conjunction with gravity tables and manual or electro nic sorting 
isvery eff icient in removing aflatoxin -contaminated kernels. Colour sorting, combined with blanching have 
beenshown to reduce aflatoxin contamination by as much as 90 %.  
4.3.2.3  Where splitting is part of the processing operation, nuts that resist splitting should b e removed. 
Theeffectiveness of sorting techniques shall be checked by regular aflatoxin analyses of the sorted 
peanutsstream or of the finished product or both. This should be done frequently enough to ensure th at the 
product iscompletely acceptable.  
4.3.2 .4 Defective (mouldy, discoloured, rancid, decayed, shrivelled, insect or otherwise damaged) 
kernelsshall be bagged separately and tagged as unsuitable for human consumption. Containers of defe ctive 
peanutsshould be removed as soon as practicable form the processing area. Materials which carry the danger 
ofcontamination by aflatoxin or which are contaminated should be diverted to non -food uses.  DRS 286:2020  
7                ©RSB2020 - All rights reserved  
 4.3.2.5  Rejected peanuts from the sorting procedure shall be destroyed or segregated from edible 
products.If they are to be used for crushing, they shall be separately bagged and tagged as unsuitable for 
direct humanconsumption in their present state.  
4.3.3  Packaging and storage of end product  
4.3.3.1  Peanuts should be packed in clear appropriate bags. If using jute, ensure  bags are not treated 
withmineral hydrocarbon based oils. All bags/cartons shall be lot identified to facilitate traceabil ity of the 
productbefore being moved to controlled storage facilities or transported.  
4.3.3.2  Peanuts that have been processed shall b e stored and transported under such conditions as 
tomaintain the integrity of the container and the product within it. Carriers shall be clean, dry, w eatherproof, 
freefrom infestation, and sealed to prevent water, rodents or insects from reaching the peanu ts. 
4.3.3.3  Peanuts shall be loaded, held and unloaded in a manner that protects from damage or water. 
Wellinsulatedcarriers or refrigerated vehicles are recommended for transport when climatic condition s 
indicatesuch a need. Extreme care should be taken to prevent condensation when unloading peanuts from 
coldstorage or from a refrigerated vehicle. In warm, humid weather, the groundnuts should be allowed  to 
reachambient temperature before exposure to external conditions . Peanuts that have been spilled are 
vulnerable tocontamination and shall not be used for edible products.  
4.4 Complementary management system  
4.4.1  The Hazard Analysis Critical Control Point (HACCP) system is an all -encompassing integrated 
foodsafety management system should be used to identify and control hazards within the production 
andprocessing system. The general principles of HACCP have been described in RS 184.  
4.4.2  When properly implemented, this system should result in a reduction of the levels of aflatoxins 
inpeanuts. The use of HACCP  as a food safety management system has many benefits over the types 
ofmanagement control systems in some segments of the food industry. At farm level there are many fac tors 
thatinfluence the aflatoxin contamination of peanuts most of which are environment ally related, such as 
weatherand insects, and these are difficult, if not impossible, to control. Particular attention sho uld be paid to 
the soilpopulation of the fungus, the health of seed material, soil moisture deficit stress at the p od formation 
and po dmaturity stages, and rains at harvest. The critical control points often do not exist at the pre -harvest 
level.However, after harvesting, the critical control points may be identified for aflatoxins produc ed by fungi 
duringdrying and storage. For example,  a critical control point could be at the end of the drying process and 
onecritical limit would be the water content/water activity.  
4.4.3  It is recommended that resources be directed to emphasizing the Good Agricultural Practices 
(GAPs)at the pre -harvest level and during drying and storage and Good Manufacturing Practices (GMPs) 
during theprocessing and distribution of various products. A HACCP system shall be built on sound GA Ps and 
GMPs.  
4.4.4  Intergrated mycotoxin control programs should incorporate HAC CP principles in the control of 
risksassociated with mycotoxin contamination of foods and feeds. The implementation of HACCP 
principlesminimizes aflatoxin contamination of peanuts through applications of preventive controls t o the 
extent feasiblein the pro duction, handling storage and processing of each peanut crop.  
  
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  DRS 286:2020  
9                ©RSB2020 - All rights reserved  
 Annex  A 
(normative)  
 
Annex title  
   
©RSB 2020 - All rights reserved                  10 
 Annex  B 
(informative)  
 
Which styles correspond to which element — Quick reference guide  DRS 286:2020  
11                ©RSB2020 - All rights reserved  
 Bibliography  
[1] RS 286: 2015 Prevention and reduction of aflatoxin contamination in peanuts — Code of practice , First 
edition  DRS 286: 2020  
 
Price based on  nnn pages  
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