Pesticide Residues, Quality Control and Regulatory Compliance
Pesticide Residues, Quality Control and Regulatory Compliance
This domain tests MRLs, pre-harvest intervals, residue analysis, formulation quality and the legal framework for pesticide registration and sale.
Core rules
- MRL is the maximum residue limit in mg/kg of food; it is a legal trading standard, not a safety threshold for an individual meal.
- PHI (pre-harvest interval) is the minimum time between the last spray and harvest; the label waiting period must be followed.
- Residue analysis uses sampling, extraction, clean-up and instruments such as GC-MS or LC-MS; QuEChERS is a common sample-preparation approach.
- Quality control checks active-ingredient content, physical properties, packaging and label claims; CIPAC methods are used for formulation analysis.
- The Insecticides Act 1968 and Insecticides Rules 1971 govern registration, manufacture, sale and use; CIB&RC registers products and the Central Insecticides Laboratory supports analysis.
Worked example
A label states PHI 7 days and MRL 0.5 mg/kg. A farmer harvests 5 days after spraying. Reasoning: the harvest is illegal because PHI is violated, even if a laboratory result later happens to be below MRL. Advise waiting the full 7 days and recording the spray date.
Traps
Confusing MRL with ADI, assuming organic produce has zero residues, ignoring PHI, and selling unregistered products are common errors.
Key distinction
MRL is a residue limit in food; ADI is an acceptable daily intake for a person.