Mycotoxin Testing in Agricultural Commodities: Aflatoxins, Ochratoxin and Sampling Risk

Testing or auditing is valuable only when the result is tied to a defined decision. The questions below should be agreed before sampling so that the sample, method, specification and response are aligned.

Field stress, insect damage, rainfall, harvest moisture, delayed drying, warehouse humidity and water ingress can affect fungal growth and toxin formation. Contamination that begins in the field can continue or redistribute during storage. Visual mould is a warning sign but is not a quantitative toxin measure, and a clean-looking lot is not proof of absence.

Some processing steps remove visibly damaged fractions or dilute contaminated material, but businesses should not rely on processing as a substitute for compliant raw material unless a validated control strategy supports it. Averages can also hide localized contamination if the legal/sampling framework is not based on the same compositing approach.

• Rank commodities by known mycotoxin susceptibility, origin, season and storage condition.
• Increase sampling intensity after moisture ingress, long storage, visible damage or supplier change.
• Keep sample reduction/grinding controlled so the final analytical portion remains representative.
• Match the requested toxin list to current commodity-specific FSSAI limits.
• Use reporting limits and quality controls appropriate to concentrations around the regulatory decision level.

FSSAI's revised mycotoxin manual is the core national analytical reference. Techniques can include chromatographic or immunochemical approaches where the specified/validated method allows, but screening and confirmatory roles should be clearly distinguished. Extraction efficiency and matrix interference are central because mycotoxins occur at low concentrations in complex foods.

A method number is not, by itself, a product specification or legal limit. The method tells the laboratory how a defined measurand is determined; the applicable regulation, product standard, consent, customer specification or validated internal plan supplies the criterion and decision context.

The sampling plan should be proportionate to lot size and heterogeneity. Multiple incremental samples distributed throughout bags, pallets, silos or moving streams are usually more defensible than one scoop. After aggregation, the laboratory or sample preparer must reduce and grind material without allowing contaminated particles to segregate away from the analytical portion.

When a result is challenged, the most difficult question is often whether the tested material represented the commercial lot. Documenting each increment, composite, reduction step and retained portion therefore strengthens both technical and commercial defensibility.

• Define lot boundaries before sampling and do not mix harvests/suppliers casually.
• Take increments from distributed spatial locations or across a moving product stream.
• Use enough aggregate mass to capture heterogeneous contamination before laboratory reduction.
• Prevent moisture change during storage and dispatch; wet samples can continue to deteriorate.
• Retain a sealed portion of the homogenized/aggregate sample when confirmation may be needed.

A result near a mycotoxin limit deserves more caution than a simple green/red cell. Sampling uncertainty, method precision, recovery and decision rule can influence conformity. Re-testing a new grab sample from the same lot can produce a very different result because of true heterogeneity; the answer is not to choose the convenient number but to follow the defined sampling and decision procedure.

Low-level detections are useful for supplier intelligence even when they do not constitute nonconformity. A rising seasonal pattern can prompt earlier drying, storage or source intervention before the legal maximum is challenged.

Long-term control uses prevention and trend intelligence. Drying, storage moisture control, aeration, pest control, stock rotation and supplier agricultural practices can reduce risk. Laboratory data should feed those programmes by showing which origin-season-storage combinations repeatedly produce detections.

The programme should also document what happens after a high result. Containment, lot trace, supplier notification, investigation and disposition should be predefined so commercial pressure does not create ad-hoc resampling decisions.

• Trend toxins separately by commodity, origin, crop year and supplier.
• Create internal alert levels below legal maxima for worsening sources where justified by risk policy.
• Audit storage and moisture controls after any significant increase, not only after a formal failure.
• Increase monitoring for long-stored or visibly compromised lots.
• Review the toxin/limit register whenever FSSAI contaminant provisions are amended.

Standards, regulations and official methods are revised over time. Before a result is used for a regulatory conformity decision, confirm the current FSSAI notification or Gazette text, the exact food or water category, the latest applicable BIS edition and amendments, the customer or statutory specification, the sampling requirement and the laboratory method/scope. FSSAI compendia are useful ready references, but the original notifications and amendments prevail where there is a conflict. This article is technical guidance, not a substitute for the applicable law, permit or product specification.

• FSSAI Manual(s) of Method(s) of Analysis – Revised Mycotoxins Manual
• FSSAI Contaminants, Toxins and Residues – amendments
• FSSAI Product Standards
• BIS Indian Standards portal
• Heavy Metals & Pesticide Analysis
• Food & Agricultural Products Testing
• Microbiological Testing
• How to Send Samples
• All Technical Blogs

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