Question

Critical head space oxygen content maintained during whole milk powder packaging is

• A. 1.0 %
• B. 2.0 %
• C. 3.0 %
• D. 4.0 %

Hint:

Milk Powder Gas Packing:
Whole Milk Powder ($26\%$ Fat) $\rightarrow$ Headspace Oxygen MUST BE $\mathbf{\le 2.0\%}$.
Gas Flushing Mixture = Nitrogen ($\text{N}_2$) + Carbon Dioxide ($\text{CO}_2$).

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Inert gas packaging of high-fat dairy powders: Whole Milk Powder (26% fat) undergoes rapid oxidative tallowy off-flavor degradation unless vacuum-gas packed with nitrogen to achieve a critical headspace oxygen content of $\le 2.0\%$ ($\le 1-2\%$).
Key Formula or Approach:
\[ \text{Whole Milk Powder Gas Packaging: Headspace } \text{O}_2 \le \mathbf{2.0\%} \quad (\text{Target: } < 1.0 - 2.0\% \text{ to prevent lipid oxidation}) \]

Step 2: Detailed Explanation:
In the packaging and storage technology of dairy powders:
- Whole Milk Powder (WMP) contains $26.0\% - 28.0\%$ milk fat, with significant free surface fat that is highly susceptible to free-radical autoxidation into aldehydes and ketones (tallowy/oxidized defect).
- To prevent oxidative spoilage and achieve a commercial shelf life of $12 - 18\text{ months}$:
1. WMP cans and multi-ply foil pouches are vacuum-evacuated and flushed with high-purity inert gas ($90\%\text{ N}_2 + 10\%\text{ CO}_2$ or $100\%\text{ N}_2$).
2. The Critical Head Space Oxygen Content maintained in the package is strictly 2.0% (or $< 2.0\%$) (B).
3. If headspace oxygen exceeds $2.0\%$, the rate of lipid peroxidation accelerates exponentially, causing rapid off-flavor development and nutritional vitamin A degradation.

Step 3: Final Answer:
Thus, the critical headspace oxygen content maintained is 2.0 %, matching option (B).