Dairy & Food Engineering-II

• Microbial Load Comparison in Dairy Commodities:
• Raw Milk:
• Fresh, unprocessed bovine milk directly from farm milking contains endogenous udder microflora, teat canal contaminants, and environmental dust/manure bacteria, easily yielding total viable counts of $10^5 - 10^7\text{ CFU/mL}$.
• In contrast, Skim milk powder, Sweetened condensed milk, and Butter undergo pasteurization, thermal evaporation, and water-activity suppression, resulting in drastically lower microbial counts.
• Conclusion: Raw Milk (Option 4).

Correct option: (4) Raw Milk

• High-Pressure Processing (HPP / Pascalization) Technology:
• Preservation Mechanics:
• Applies isostatic hydrostatic pressures ($100 - 800\text{ MPa}$) uniformly throughout food packages without thermal heat.
• Enzyme and Spoilage Inactivation: Inactivates vegetative spoilage cells and destabilizes enzymes.
• Retention of Sensory Qualities: Leaves covalent bonds unaffected, preserving small molecular weight vitamins, natural colors, textures, and volatile aroma profiles.
• Statement (B) is false: Bacterial endospores (e.g., Clostridium botulinum) resist high hydrostatic pressures at ambient temperatures unless combined with heat.
• Conclusion: (A), (C) only (Option 2).

Correct option: (2) (A), (C) only.

• Thermodynamic Triple Point of Pure Water:
• Equilibrium State:
• The unique thermodynamic state where solid ice, liquid water, and water vapor coexist in simultaneous thermodynamic equilibrium.
• Exact Physical Constants:
• Temperature: $0.01^\circ\text{C}$ ($273.16\text{ K}$ or $32.018^\circ\text{F}$).
• Pressure: $611.657\text{ Pascals}$ ($6.11657\text{ mbar}$ or $4.587\text{ mmHg}$).
• Fundamental baseline reference for lyophilization (freeze drying) cycles in food engineering.
• Conclusion: Temperature: 0.01°C; Pressure: 611.657 pascals (Option 1).

Correct option: (1) Temperature: 0.01°C; Pressure: 611.657 pascals

• Psychrometric Processes in Environmental Control:
• Summer air conditioning involves cooling and moisture condensation; in evaporative cooling, adiabatic water evaporation increases relative humidity (Statement D).
• Official Answer Key: Designated A, C, D only as the credited combination.
• Conclusion: A, C, D only (Option 3).

Correct option: (3) AC.D only