ICAR AIEEA-PG / PGS — Code 18 Food Science Technology · India · ICAR through the National Testing Agency
Original practice questions written to the published syllabus · not past papersReducing and using food-industry waste: characterisation and treatment of food-plant effluents, recovery of by-products, water and energy reduction, life-cycle assessment and circular-economy approaches. General agricultural waste engineering is in Agricultural Engineering's waste-management-environmental-engg.
In the exams: GATE XE-G Section 3 (waste utilisation); ICAR AIEEA-PG Code 18 Unit III (effluent treatment, waste solids upgrading); ICAR AICE 41 (waste disposal of food processing plants)
How our questions for ICAR AIEEA-PG / PGS spread across the units of Food Waste Valorisation, By-products & Sustainable Food Processing. Difficulty: 21 easy, 36 medium, 1 hard.
| Recovery of by-products from fruit, cereal, dairy, meat and fish processing | 8 | |
| Characteristics of food-industry wastes: BOD, COD and solids | 7 | |
| Anaerobic digestion of food-processing waste | 6 | |
| Energy efficiency and carbon footprint | 6 | |
| Food loss and waste along the chain | 5 | |
| Effluent treatment for food plants: primary, secondary and tertiary | 5 | |
| Water reuse and water footprint in food plants | 5 | |
| Circular economy and upcycled foods | 5 | |
| Environmental regulation for food industries | 5 | |
| Extraction of bioactives from by-products | 4 | |
| Life-cycle assessment of food products | 2 |
Choose an answer, then open the working. Each explanation says why the right answer is right and why the others are not.
In which part of the chain are losses of perishable produce often proportionally largest in many low-income countries?
C. Post-harvest handling, storage and transport
Lack of cold chains, storage, drying and roads causes large post-harvest losses in many low-income settings, while household waste dominates in many higher-income countries.
Further reading: FAO, State of Food and Agriculture 2019; UNEP Food Waste Index Report
A dairy effluent is diluted 1 in 100 for a BOD test. Dissolved oxygen falls from 8.5 to 4.0 mg/L in 5 days. What is the BOD₅?
B. 450 mg/L
BOD₅ = (D₁ − D₂)/P = (8.5 − 4.0)/0.01 = 450 mg/L. 4.5 mg/L forgets the dilution; 850 mg/L divides the initial DO by P; 45 mg/L uses a dilution of 1 in 10.
Further reading: Metcalf & Eddy, Wastewater Engineering: Treatment and Resource Recovery
An aeration tank of 3000 m³ receives 1000 m³ of effluent per day. What is the hydraulic retention time?
B. 72 hours
HRT = V/Q = 3000/1000 = 3 days = 72 hours. 3 hours confuses days with hours; 0.33 inverts the ratio; 8 hours takes a third of a day.
Further reading: Metcalf & Eddy, Wastewater Engineering: Treatment and Resource Recovery
What is the typical methane content of biogas from anaerobic digestion?
B. About 50 to 70 per cent
Biogas is mainly methane (about 50–70%) and carbon dioxide, with traces of H₂S; upgrading is needed to reach near-pure biomethane.
Further reading: Metcalf & Eddy, Wastewater Engineering; Galanakis, Food Waste Recovery
How is chitosan obtained from shrimp shells?
D. Demineralise, deproteinise, then deacetylate chitin
Shells are treated with acid to remove minerals and alkali to remove protein, giving chitin, which is deacetylated with strong alkali to chitosan.
Further reading: Galanakis, Food Waste Recovery; Waldron, Handbook of Waste Management and Co-product Recovery
What is the main use of brewers' spent grain?
A. Cattle feed
Spent grain, the largest brewery by-product, goes mostly to cattle feed, with growing use as dried food ingredients. The other uses are not standard.
Further reading: Galanakis, Food Waste Recovery; Waldron, Handbook of Waste Management and Co-product Recovery
In counter-current washing of vegetables, where does clean water enter?
B. At the last stage, then flowing back to the earlier stages
Clean water meets the cleanest product last and then flows backwards to wash dirtier product, cutting water use while keeping the final rinse clean.
Further reading: Hoekstra, Water Footprint Assessment Manual; ISO 14040/14044; GHG Protocol
Under the GHG Protocol, which scope covers emissions from electricity purchased by a food factory?
B. Scope 2
Scope 2 is indirect emissions from purchased electricity, steam, heat and cooling. Scope 1 is direct; scope 3 is other value-chain emissions.
Further reading: Hoekstra, Water Footprint Assessment Manual; ISO 14040/14044; GHG Protocol
What is aquafaba, an upcycled ingredient?
A. Chickpea cooking liquid used as an egg-white substitute
Aquafaba, the cooking liquid of chickpeas, whips like egg white. The other descriptions are fish sauce, cow water and cascara.
Further reading: FAO, State of Food and Agriculture 2019; UNEP Food Waste Index Report
What does the "polluter pays" principle mean?
B. Those who cause pollution bear the costs of it
The principle places the costs of preventing and remedying pollution on those responsible for it.
Further reading: FAO, State of Food and Agriculture 2019; UNEP Food Waste Index Report
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