1. Sources of Cereal Contamination
STRENGTHENING/IMPROVING THE CAPACITY OF
NIGERIAN RICE/MAIZE PRODUCERS ORGANIZATION
Sources of Cereal Contamination

2. What is contamination?

3. Contamination is simply the action or state of making or being made impure by polluting or poisoning.

4. Grains/Cereals Contamination
The exteriors of harvested grains retains some of the natural flora they had while growing plus contamination from air, dust, soil , & other sources.  Freshly harvested grains contain loads of a few thousand to million of bacteria.
There are three major sources of grain contamination.
Physical contamination
Biological contamination
Chemical contamination

5. Physical contamination
1. Rodents
What connection does rodents and lassa fever have?

6. Physical contamination
2. Anthropod fragments

7. Physical contamination
3. Exuviae
sloughed skin of an animal, especially of an insect larva

8. Physical contamination
4. Feaces
Cat are proven biological control for rodents in grain stores

9. Physical contamination
5. Internally feeding insects
Wheat weevil
Rice weevil

10. Physical contamination
5. Internally feeding insects cont’d
Maize weevil

11. Biological contamination
Flies, cockroaches, silverfish, wasp, rodents disseminate more than 100 species of pathogenic viruses, bacteria and fungi.
They increase occurrence of mycotoxins. This poses a considerable risk to human food and animal feed safety

12. Chemical contamination
Bacteria and fungi cause microbiological contamination in cereals. They produce chemicals such as
Heavy metal presence in grains
Storage Pests produce volatile chemicals which are responsible for bad smell of infested grains
Pesticides also contaminate grains in storage if not applied correctly (in dosage, active ingredient, concentration and quantity
Microbiological contaminants: these are from living things that are not easily visible to the eyes except they come under microscope
Aflatoxins
Ochratoxins
Moniliformin

13. No so visible

14. Aflatoxin: a chemical contaminant
Quick Facts
Aflatoxins are formed as a result of fungal growth
They don’t go even after the fungi that introduces them dies
Those who consume contaminated commodities have severe health injuries including hemorrhaging, acute liver damage, edema (swelling), digestive difficulties, and possibly death, usually within a week of exposure
The biggest and best known health effect of aflatoxin is liver cancer
You cannot see, smell, feel or taste aflatoxin in grains
25% of the food produced worldwide is contaminated with aflatoxins. Due to the increasing recognition of the impact of aflatoxins on human health, food regulatory authorities have set and enforced limits for aflatoxins in traded food.

15. Maize contaminated with aflatoxin

16. At what stages does aflatoxin contamination occur?
It begins during pre-harvest and can be worsened by inappropriate harvesting, handling, storage, processing, and transport practices
Droughts, high temperatures, low soil fertility, pest and other stresses that affect plant growth and vigor increase the likelihood of fungal infection as well as the levels of aflatoxins produced by the Aspergillus fungi.

17. How to prevent/handle aflatoxin contamination
Aflatoxin contamination can be prevented by application of good agricultural practices in crop cultivation and good management practices in post-harvest food handling.
Destroy or bury deep infected cobs or grains. Why? This is because they are so stable and stubborn they are not easily removed by cooking, washing, milling or other common food treatment

18. Other contaminants Hair Water Residue in containers/bags
Metals from processing machines

19. Non-poisonous contaminants
Physical Mixture of different types of grains
Physical Mixture showing crop off-types
This is common among maize and rice farmers.
This is common among maize and cowpea farmers
What is the consequence of this paddy mix-up?

21. Mungode