The US Public Health Service (USPHS) standard for homogenized milk requires that after 48 hours of quiescent cold storage at $4-5^\circ\text{C}$, the fat percentage in the top $100\text{ mL}$ of a quart bottle must not exceed that of the remaining thoroughly mixed milk by more than:
Options:
(A) $10\%$ of its own value
(B) $50\%$
(C) $1\%$
(D) $0\%$
Answer Key:
A
Step-by-Step Solution & Explanation
USPHS specifies: $\frac{\text{Fat}\%_{\text{top}} - \text{Fat}\%_{\text{remainder}}}{\text{Fat}\%_{\text{top}}} \times 100 \le 10\%$. Homogenizers operating at $15-20\text{ MPa}$ shatter fat globules from $3-4\text{ \mu m}$ down to lt; 1-2\text{ \mu m}$ to satisfy this rule.