Question

Sterilization temperature-time employed for evaporated milk is

• A. 95°C to 110°C for 15 min.
• B. 116°C to 118°C for 15 min.
• C. 120°C to 125°C for 15 min.
• D. 128°C to 132°C for 15 min.

Hint:

Evaporated Milk Processing: IN-CAN STERILIZATION = $\mathbf{116^\circ - 118^\circ\text{C for } 15\text{ min}}$. Rotary motion prevents burn-on and promotes uniform heat penetration.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Retort thermal sterilization of canned concentrated milks: canned unsweetened evaporated milk is batch-sterilized in rotary pressure retorts at 115°C to 118°C for 15 to 20 minutes to achieve commercial sterility and optimal viscosity without curdling.
Key Formula or Approach:
\[ \text{Retort Sterilization Regime: } T = \mathbf{116^\circ\text{C to } 118^\circ\text{C}} \quad \text{held for } \mathbf{15 \text{ min}} \quad (F_0 \ge 4.0 - 5.0) \]

Step 2: Detailed Explanation:
In the technology of canned evaporated milk manufacture:
- Unsweetened evaporated milk ($26\% - 31\%$ total solids, $8\% - 9\%$ fat) is sealed in metal cans and subjected to in-container retort sterilization:
1. The thermal process must destroy all vegetative pathogens and heat-resistant bacterial endospores (specifically Geobacillus stearothermophilus and Clostridium botulinum).
2. The standard industrial sterilization temperature-time combination is 116°C to 118°C for 15 minutes (or 115°C--120°C for 15--20 min) (B) in continuous rotary reel or batch retorts.
3. This controlled thermal profile ensures complete commercial sterility, creates the desired velvety body via controlled incipient protein gelation, and prevents excessive brown discoloration or caramelized cooked defect.

Step 3: Final Answer:
Therefore, the sterilization time-temperature is 116°C to 118°C for 15 min, corresponding to option (B).