Which of the following sanitary and safety features are mandatory in a commercial continuous HTST milk pasteurization plant?
Options:
(A) Flow Diversion Valve (FDV) that automatically diverts sub-pasteurized milk back to the balance tank if temperature drops below the legal limit ($71.7^\circ\text{C}$)
(B) Booster pump installed to ensure pasteurized milk is maintained at higher hydraulic pressure than raw milk in the regenerator section to prevent cross-contamination
(C) Holding tube sloped continuously upward toward the FDV at a minimum gradient of $2\%$ ($1/50$) to prevent air entrapment
(D) Open wooden cooling towers directly exposing pasteurized milk to atmosphere
Answer Key:
A, B, C
Step-by-Step Solution & Explanation
1. FDV diverts any under-temperature milk instantly (A is mandatory).
2. Positive differential pressure prevents leakage from raw to pasteurized side across plates (B is mandatory).
3. Sloped holding tube eliminates air pockets that could alter holding residence time (C is mandatory).
4. Milk must flow strictly within hermetically sealed, sanitary stainless steel heat exchanger plates without ambient exposure (D is false).