PHILIPPINE NATIONAL STANDARD  PNS/BAFS 27:xxxx  
Code of practice for the prevention and reduction of aflatoxin contamination in corn  
Working draft  
For WTO SPS Notification  
ii 
 
 
 
 Foreword  1 
 2 
The Philippine National Standard (PNS) Code of practice for the prevention and 3 
reduction of aflatoxin contamination in corn (PNS/BAFPS 27:2008)  was developed to 4 
provide uniform guidance for all corn stakeholders, as well as serve as common reference 5 
and basis for compliance to Good Agricultural Practices (GAP) for corn.  This code 6 
provides adequate measures to manage aflatoxin contamination in th e supply chain 7 
following the framework of farm to table approach to food safety. I t also provides 8 
guidance to all persons involved in producing and handling corn intended for human and 9 
animal consumption for entry into local and international trade.  10 
 11 
In 20 17, the Bureau of Agriculture and Fisheries Standards (BAFS) to ok the initiative to 12 
revise the Standard to account for results of recent studies and advances for the 13 
prevention and reduction of aflatoxin contamination in corn. This revision is in 14 
accordanc e with  the protocol of the Bureau’s Standards Development Division  (SDD ) to 15 
review and, if applicable, revise  standards every two (2) years, especially those that pose 16 
risk to consumer safety and health. A T echnical Working Group (TWG) fo r the revision of 17 
the Standard  was created and authorized under Special Order No. 523 Series of 2017. 18 
The TWG was composed of the following agencies and institutions: National Food 19 
Authority (NFA), National Food Authority – Food Development Center (NFA -FDC), 20 
Bureau of Anima l Industry (BAI), Food and Nutrition Research Institute (FNRI), 21 
Philippine Center for Postharvest Development and Mechanization (PHilMech), 22 
University of the Philippines Los Baños (UPLB), and Department of Agriculture (DA) – 23 
Corn Program.  24 
 25 
This document wa s drafte d in accordance with the editorial rules of the BPS Directives, 26 
Part 3.  27 
 28 
This Standard cancels and repeals PNS/BAFPS 27:2008. 29  
 
  
PHILIPPINE NATIONAL STANDARD  PNS/BAFS 27 :xxxx  
Code of practice for the prevention and reduction of aflatoxin contamination in corn  
Working draft  
For WTO SPS Notification  
1 
 
 
 
 1         Scop e 30 
 31 
This docu ment is intended to provide guidance  to all pe rsons  involv ed in produc ing and 32 
hand ling corn for entry into local  and international trade intended  for human and animal 33 
consu mpti on. This code  cons titut es from on-farm production to on-farm/off -farm 34 
storage. This code  of practice recomm ends  measu res that shou ld be implemented by all 35 
persons  that ha ve the responsibility of assu ring that food and feed are safe from aflat oxin. 36 
 37 
2         Normative references 38 
 39 
The following documents, in whole or in part, are normatively referenced in this 40 
document and are indispensable for its application. For dated references, only the edition 41 
cited applies. For undated references, the latest edition of the referenced document 42 
(including any amendments) applies.  43 
 44 
PNS/BAFPS 20:2008 , Good Agricultural Practices (GAP) for Corn  45 
 46 
3         Terms and d efinitions  47 
 48 
 For the purposes of this Code, the following terms and definitions apply:  49 
 50 
3.1  51 
aflatoxin  52 
group of highly poisonous and carcinogenic compounds which are produced by strains 53 
of the fungi, Aspergillus flavus  Link and Aspergillus parasiticus  Speare on suitable 54 
substrate such as corn, peanuts, copra, and other oilseeds, etc. Aflatoxin content is 55 
expressed in µg/ kg  56 
 57 
3.2 58 
corn st akehold ers 59 
includes  corn farmer s, traders and users 60 
 61 
3.3 62 
corn  63 
corn on cob and shelled corn of Zea mays L. 64 
 65 
3.4  66 
foreign matter  67 
all matters other than corn grains such as sand, gravel, dirt, pebbles, stones, lumps of 68 
earth, clay mud, chaff, straw and seeds of other crops  69 
 70 
3.5 71 
moisture content  (MC)  72 
amount of moisture in the corn on cob or shelled corn expressed in percent (%)  73 
 74 
 75 
 76 
  77  
 
  
PHILIPPINE NATIONAL STANDARD  PNS/BAFS 27 :xxxx  
Code of practice for the prevention and reduction of aflatoxin contamination in corn  
Working draft  
For WTO SPS Notification  
2 
 
 
 
 3.6 78 
physiological maturity  79 
required number of days of the corn to mature (days to maturity) usually characterized 80 
by the presence of the black layer at the base of the corn kernel. The black layer indicates 81 
that the corn is already mature  82 
  83 
4        Recommended practices based on good agricultural practices (GAP) for corn  84 
 85 
4.1      Farm production practices  86 
 87 
4.1.1 Observe proper land preparation for healthy and uniform growth of the corn plant  88 
as recommended by the PNS for GAP Corn (PNS/BAFS 20:2008).  89 
 90 
4.1.2  Production  areas must be kept clean and tidy at all times. Field sanitation 91 
practices must always be maintained. Farm debris as sources of inoculum must be 92 
removed to manage population of  A. flavus  or A. parasiticus . If possible, a one ( 1) month 93 
to two ( 2) months fallow period will be observed before planting.  94 
 95 
4.1.3  The recommended practices for soil and soil nutrients are in accordance with  the 96 
PNS for GAP Corn (PNS/BAFS 20:2008).  97 
 98 
4.1.4 Use varieties or hybrids that are adaptable to the locality and approved by 99 
National  Seed Industry Council (NSIC) as seed material.  100 
 101 
4.1.5  Maintain    the   recommended   row   and   plant   spacing   and thin to optimum 102 
population density to   avoid   overcrowding. This can result in reduced yield due to 103 
competition for soil nutrients and sunlight. Overcrowding of plants may lead to humid 104 
and warm conditions in the canopy which favors insect, microorganism , and disease 105 
development. To reduc e sources of infection, roguing of diseased plants should be 106 
implemented.   107 
 108 
4.1.6 Observe  the appropriate method and time in applying the recommended 109 
combination and amount of fertilizers based on the result of soil analysis. Nutrient 110 
deficiencies or over fertilization particularly nitrogen (N) may lead to greater 111 
susceptibility to insect pest s and diseases.  112 
 113 
4.1.7 Seed inoculant may be used to supplement part of the corn plant nutrient 114 
requirement.  115 
 116 
4.1.8  Apply  Integrated Pest Management (IPM) such as using biological control agents 117 
and natural enemies of pests and disease s, and the proper us e of pesticide only when 118 
necessary.  119 
 120 
4.1.9 Practice appropriate weed control measures such as proper land preparation, off - 121 
barring at 15 to 20  days after planting (DAP) , and/or hilling -up at 25 to 30 DAP to 122 
minimize weed population. Care should be taken during cultivation to avoid damage to 123 
the plant.  124 
 125  
 
  
PHILIPPINE NATIONAL STANDARD  PNS/BAFS 27 :xxxx  
Code of practice for the prevention and reduction of aflatoxin contamination in corn  
Working draft  
For WTO SPS Notification  
3 
 
 
 
 4.1.10 Maintain the water requirement to avoid moisture stress particularly during 126 
flowering up to the maturation stage , if applicable .  At these stages, t he crop is mor e 127 
susceptibl e to aflatoxin contamination.  128 
 129 
4.1.11 If detopping of corn plants is to be practiced, this should be done after 130 
physiological maturity has been attained. Early detopping could lead to shriveled and 131 
inferior corn grains.  132 
 133 
4.1.1 2 Practice crop rotation to minimize build -up of aflatoxin producing fungi inherent 134 
in the soil.  135 
 136 
4.2      Practices during harvest  137 
 138 
4.2.1 Farm workers involved in harvesting and succeeding operations should wear 139 
appropriate  clothing and protective gadgets such as long sleeves and dust mask.  140 
 141 
4.2.2 Harvest corn at physiological maturity as recommended (approximately 100 to 142 
120 DAP for yellow corn and 90 to 100 DAP for white corn). Harvesting should be 143 
completed in the shortes t time possible especially during rainy season. Care must be 144 
exerted to prevent damage and contamination of corn ears with soil. Use clean mats, 145 
screens , and/or other suitable underlays to prevent corn ears from soil or foreign matter 146 
contamination.  147 
 148 
4.2.3 As much as possible, harvesting should be done on sunny days.  149 
 150 
4.2.4 Dehusking is discouraged during rainy season  to prevent A. flavus  infection .  151 
 152 
4.2.5  Air-dry immediately the unhusked ears in a well -ventilated  area to minimize 153 
fungal contamination.  154 
 155 
4.2.6 Use clean bags or other suitable containers for the newly harvested corn ears.  156 
 157 
4.2.7 Before using machines for harvesting and other post -harvest  operations, ensure 158 
that all the equipment to be used are functional, clean , and well -maintained to minimize 159 
undue damage to the grain.  160 
 161 
4.2.8 Sort -out and discard corn ears that show visible signs and symptoms of premature 162 
sprouting, insect  damage,  or microbial  infection . 163 
 164 
4.2.9 Discarded corn ears should be disposed in a compost pit away from the 165 
production area.  The recommended depth of the compost pit is one to two (1-2) meters.  166 
 167 
4.3      Practices after harvest  168 
 169 
4.3.1   Hauling and  piling  170 
 171 
Haul newly harvested corn ears immediately after harvest. Hauling or transport facilities 172 
(e.g. wagons, trucks) to be used for collecting and transporting the harvested corn from 173  
 
  
PHILIPPINE NATIONAL STANDARD  PNS/BAFS 27 :xxxx  
Code of practice for the prevention and reduction of aflatoxin contamination in corn  
Working draft  
For WTO SPS Notification  
4 
 
 
 
 the farm to drying facilities or to storage area should be clean, dry, and fr ee from insects 174 
and visible microbial growth.  For corn ear with husk, the recommended maximum days 175 
of piling is three (3)  days.  176 
 177 
4.3.2   Shelling  178 
 179 
4.3.2.1 Clean, dry , and properly calibrated mechanical sheller  should be used  to minimize 180 
mechanical damage to the kernels and further avoid aflatoxin contamination.  181 
 182 
4.3.2.2 Before  shelling, dry the corn ears to 18-20% MC to minimize grain damage. At this 183 
MC, the seed can overcome mechanical damage brought about by the shelling ma chine.  184 
 185 
4.3.2.3 Shelled corn  should be placed in clean  and dry sack containers . Avoid using 186 
containers previously used for fertilizer.  187 
 188 
4.3.2.4 If immediate shelling is not possible, temporarily store the corn ears in cribs or  189 
any structure with good ventilation.  190 
 191 
4.3.3   Drying  192 
 193 
4.3.3.1  Dry the corn grains to 13 to 14 % MC  within 48 hours after shelling . Ensure that 194 
corn has been dried uniformly to 13 % or 14 % MC. This can be determined with the use 195 
of a calibrated moisture tester. The measurement of the moisture content of the corn 196 
should be determined from a representative sample randomly taken from the  batch.  197 
 198 
4.3.3.2 When using a mechanical dryer, the air -drying temperature should be within 43°C 199 
to 50°C. Do not expose corn grains to higher temperature to avoid stress cracks.  200 
 201 
4.3.3. 3 In case of sun drying, the shelled corn should be protected from dir ect contact 202 
with the soil. Avoid mixing of dry grain with wet grain or any foreign matter.  203 
 204 
4.3.3. 4 If immediate drying is not possible , temporar ily store the corn ears in cribs or 205 
other well -ventilated structures to prevent heat build -up and microbial gro wth.  206 
 207 
4.3.3. 5 Clean suitable containers should be used for the dried corn grains.  208 
 209 
4.3.4   Transport  210 
 211 
4.3.4. 1 The bagged corn  grains  should be moved to a suitable storage or processing area 212 
as soon as possible after drying.  213 
 214 
4.3.4.2 To avoid re-wetting of bagged corn grains during transport , appropriate covering 215 
for the container  should be used . Bagged c orn grains to be transported should be 216 
properly stacked inside the transport vehicle . 217 
 218 
 219 
 220 
 221  
 
  
PHILIPPINE NATIONAL STANDARD  PNS/BAFS 27 :xxxx  
Code of practice for the prevention and reduction of aflatoxin contamination in corn  
Working draft  
For WTO SPS Notification  
5 
 
 
 
 4.3.5   Storage  222 
 223 
4.3.5. 1 The storage structure should be made of durable materials and should be able to 224 
withstand strong winds, rain , and earthquakes. It should be situated in areas where there 225 
is no flooding. The design of the warehouse should be able to meet the following 226 
minimum requirements , namel y: 227 
 228 
a.     prevent re -wetting of dry corn grains;  229 
b.     prevent entry of insects,  birds and rodents; and  230 
c.      provide good ventilation to the stored corn.  231 
 232 
4.3.5.2 During storage, follow the first -in first -out (FIFO) principle.  233 
 234 
4.3.5. 3 The MC of cor n should be maintained at 13 to 14 % at all times in storage to 235 
prevent the growth of A. flavus  and/or A. parasiticus.  236 
 237 
4.3.5. 4 Observe proper piling of bagged corn grains inside the warehouse . 238 
 239 
4.3.5.5 Maintain cleanliness at all times to prevent pest  infestation and disease infection.  240 
 241 
4.3.5.6 Periodically measure the temperature of the stored corn during storage. A 242 
temperature rise may indicate microbial growth and/or pest  infestation. Visually check 243 
corn for evidence of mold growth and separate the infested/ infected portion.  Subject 244 
infected samples for aflatoxin analysis if possible.  245 
 246 
4.3.5. 7 If the corn stocks will be stored for more than a month, pest control 247 
administration should be in accordance with PNS Good Warehousing Practices for 248 
Bagged Grains (PNS/BAFS 193:2017 ).  249  
 
  
PHILIPPINE NATIONAL STANDARD  PNS/BAFS 27 :xxxx  
Code of practice for the prevention and reduction of aflatoxin contamination in corn  
Working draft  
For WTO SPS Notification  
6 
 
 
 
 Bibliography  250 
 251 
CAC/RCP 55. 2004. Code of Practice for the Prevention and Reduction of Aflatoxin  252 
Contamination in Peanuts. 7 pp.  253 
 254 
CAC/RCP 51. 2003. Code of Practice for the Prevention and Reduction of Mycotoxin 255 
Contamination in Cereals, including annexes on Ocratoxin A, Zearalenone, Fumonisins 256 
and Tricothecenes. 8 pp.  257 
 258 
CAC/RCP 45. 1997. Code of Practice for the Reduction of Aflatoxin  B1 in Raw Materials 259 
and Supplemental Feeding Stuffs for Milk Producing Animals. 4 pp.  260 
 261 
DA-BAFPS.  2004. Philippine National Standards (PNS) for Shelled Corn. 10:2004. DA - 262 
BAFPS.  2004. Philippine National Standards (PNS) for Corn Grits. 15:2004.  263 
 264 
Department of Agriculture (Labois, R. V. et. al) (eds). 2004. Integrated Crop Management  265 
Module and Manual.  266