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Food Science and Technology QUESTION #5957
Question 1
In dairy plant design, 'pasteurized product contamination by raw milk' in plate heat exchangers (PHE) is prevented by:
  • Using thicker gaskets between raw and pasteurized milk channels
  • Designing the regeneration section with higher pressure on the pasteurized side (\(\geq 14\;\text{kPa}\) or \(2\;\text{psi}\) above raw milk pressure) than the raw milk side✔️
  • Using separate PHEs for raw and pasteurized milk
  • Monitoring conductivity of milk streams
Correct Answer Explanation
In HTST PHE regeneration sections, regulations require that pasteurized milk pressure exceed raw milk pressure by \(\geq 14\;\text{kPa}\) (\(2\;\text{psi}\)), ensuring that any leakage is from pasteurized to raw (not raw to pasteurized), preventing contamination of the pasteurized product stream.