Agricultural/Bioengineering Post-Harvest Technology 2 — Questions and Answers
Question 1: What does the term 'precooling' mean in fresh produce handling?
- Warming produce before harvest to improve flavor
- Rapidly removing field heat from produce after harvest (Correct answer)
- Applying fungicide before storage
- Grading produce by color before packing
Correct answer: Rapidly removing field heat from produce after harvest
Precooling rapidly lowers produce temperature after harvest to slow respiration, decay, and moisture loss.
Question 2: Which precooling method is most suitable for leafy vegetables such as lettuce?
- Forced-air cooling
- Vacuum cooling (Correct answer)
- Hydrocooling
- Room cooling
Correct answer: Vacuum cooling
Vacuum cooling rapidly removes heat through evaporation from high-surface-area crops like lettuce in 20–30 minutes.
Question 3: Modified atmosphere packaging (MAP) for fresh-cut produce primarily aims to:
- Increase oxygen to prevent browning
- Balance O₂ and CO₂ inside the package to slow respiration (Correct answer)
- Remove all gas from the package
- Add ethylene to accelerate ripening for retail
Correct answer: Balance O₂ and CO₂ inside the package to slow respiration
MAP creates a modified gas environment around produce to reduce respiration rate and extend shelf life.
Question 4: Grain stored at a temperature of 50°F (10°C) compared to 70°F (21°C) will:
- Lose moisture faster
- Have a significantly longer safe storage life (Correct answer)
- Show higher insect activity
- Require more aeration
Correct answer: Have a significantly longer safe storage life
Lower temperatures reduce the metabolic activity of grain, mold, and insects, extending safe storage life considerably.
Question 5: Aflatoxin contamination in stored corn and peanuts is produced by which organism?
- Fusarium species
- Penicillium species
- Aspergillus species (Correct answer)
- Rhizopus species
Correct answer: Aspergillus species
Aspergillus flavus and A. parasiticus produce aflatoxins, potent carcinogens, in warm, humid grain storage conditions.
Question 6: The term 'cold chain' in fresh produce logistics refers to:
- The sequence of freezing and thawing steps during processing
- Maintaining continuous refrigeration from harvest to retail sale (Correct answer)
- Using liquid nitrogen in packaging
- The supply chain for frozen meat products only
Correct answer: Maintaining continuous refrigeration from harvest to retail sale
The cold chain is an unbroken temperature-controlled supply chain that preserves produce quality from farm to consumer.
Agricultural/Bioengineering Post-Harvest Technology 2
What does the term 'precooling' mean in fresh produce handling?