Mycotoxins: prevent, detect, manage a doubtful batch

This lesson is part of Making feed on the farm, expert level specialisation. It opens to every registered student, from free registration. Levels 1 to 5 and the tracks remain readable by everyone.

Level 11 presented mycotoxins in one section: invisible poisons of moulds, maize at 14%, grain sorting. The expert must go further, because in a hot and humid climate it is the number one risk of a feed workshop, and because it is managed with figures: which toxins, produced by which moulds, under which conditions, at which thresholds, detected how, and above all what to do with a 20-tonne lorry-load you have doubts about. This lesson gives the complete map of the mycotoxins that matter in Côte d'Ivoire, the prevention chain from field to mixer, the detection methods from the simplest to the surest, the international indicative thresholds, a worked exposure calculation, and the written procedure for a doubtful lot.

• ✓Distinguish the main mycotoxins (aflatoxins, fumonisins, trichothecenes, ochratoxin, zearalenone), their moulds, their raw materials and the conditions in which they appear
• ✓Apply the prevention chain from field to mixer and understand why mycotoxin sampling requires 10 kg
• ✓Choose the suitable detection method (eye, UV lamp, rapid kit, laboratory) and read a result in micrograms per kilo against indicative thresholds
• ✓Calculate the exposure of a finished feed from its raw materials and apply the doubtful-lot procedure

1. The map of the mycotoxins that matter in Côte d'Ivoire
2. The prevention chain, from field to mixer
3. Detecting: from the eye to the laboratory, and the sample problem
4. Indicative thresholds and the exposure calculation
5. The doubtful-lot procedure
6. On the birds: what is observed, and what is done
7. Going further

• •Families: aflatoxins (Aspergillus, hot damp storage, maize-groundnut-cotton, liver and defences), fumonisins and trichothecenes (Fusarium, in the field, maize), ochratoxin A (storage, kidneys), zearalenone (little effect in poultry); often several together, effects add up.
• •Prevention: water and time (14% at bagging in less than 72 h, stock ≤ 6 to 8 weeks, pallets, air, stack ≤ ambient + 5 °C), insects (cleanliness, rotation, authorised protection only), receiving (mouldy ≤ 2%, pierced ≤ 5%), workshop dry-brushed, finished feed used within 2 to 3 weeks.
• •Detection: eye-nose-hand, UV lamp 365 nm (indicator, 4 to 5 fluorescent grains = suspect), rapid kit (10 to 15 min, decision at unloading), laboratory (ELISA, HPLC, reference); 10 kg sample in 100 increments, all ground, 1 kg + 1 kg twin.
• •Indicative benchmarks (poultry feed): aflatoxin B1 20 µg/kg (10 young), ochratoxin A 100, DON 5,000, fumonisins 20,000, T-2 250; prudent internal thresholds: aflatoxin 10, starter 5; national texts and laboratory are the authority.
• •Exposure = sum of kg × µg/kg ÷ 100; maize 63.3 kg at 25 + groundnut 8 kg at 60 = 20.6 µg/kg: above the benchmark; doubtful lot: isolate, 10 kg, kit, laboratory, decide by the table, never dilute, clean, note, veterinarian for the birds.