Management of agricultural produce
Storage, preservation, packaging, adulteration, additives and quality marks (ISI, AGMARK, FPO).
After the harvest
A large part of food is lost after harvest because of pests, rodents, moisture and poor handling. Good management covers storage, preservation, packaging and quality control.
Storage
Grain must be dried before storage, since moisture encourages fungi and insects. Small-scale structures include the metal Pusa bin and traditional kothars; large-scale storage uses warehouses, silos, cold storage for fruits and vegetables, and CAP (cover and plinth) storage, where bags are stacked on raised plinths and covered. Fumigation and regular cleaning prevent pest attack.
Preservation
Food spoils because of microbes and enzymes. Methods include drying, salting, adding sugar (jams), pickling in oil or vinegar, refrigeration and freezing, pasteurisation (heating milk to a moderate temperature and cooling it quickly), canning, irradiation and chemical preservatives such as sodium benzoate and potassium metabisulphite.
Packaging
Packaging protects food from moisture, air, light and contamination, and carries information such as ingredients, date of manufacture and expiry.
Adulteration and additives
Adulteration is adding cheaper or harmful substances to food or removing nutrients from it. Examples: metanil yellow in turmeric or dal, brick powder in chilli powder, papaya seeds in black pepper, argemone oil in mustard oil (it causes epidemic dropsy), water or starch in milk (starch turns blue with iodine), and chalk in flour. Permitted food additives (colours, flavours, preservatives, emulsifiers) are allowed within limits. India's earlier Prevention of Food Adulteration Act, 1954 was replaced by the Food Safety and Standards Act, 2006, which created FSSAI.
Quality marks
- ISI mark: given by the Bureau of Indian Standards for industrial and consumer products such as electrical goods and cement.
- AGMARK: certifies agricultural produce such as pulses, spices, honey and ghee, under the Agricultural Produce (Grading and Marking) Act, 1937.
- FPO mark: for processed fruit and vegetable products such as jams, squashes and pickles, from the Fruit Products Order.
Key points
- Dry grain before storage; moisture invites fungi and insects.
- Starch in milk is detected by the iodine test (blue colour).
- Argemone oil in mustard oil causes epidemic dropsy.
- AGMARK = farm produce; ISI = industrial goods; FPO = processed fruit products.
Exam tips
- Match the mark to the product: honey or ghee → AGMARK; electric iron → ISI; mango squash → FPO.