Records of Decision - DEIM Task 1.11.12 Pressure Differential Controllers (PDC)/Gauges and Task 1.11.07 Heating/Cooling

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Question or Description of Problem:

  1. What are the minimum requirements of the heating section of the HTST (high temperature short time) with respect to pressure differentials?


Task 1.11.12 assesses the actual pressure devices used, i.e. gauges or pressure differential controllers. This task focuses on the general conditions, location of devices, accuracy, sealing requirements and records.

Task 1.11.07 assesses the actual pressure differential requirement, but focuses on the cooling section rather than the heating section and it implies that the requirements for both the heating and cooling section are the same, when in fact they are not. It is not clear what the pressure differential requirements are for the heating section.


For the heating section of the HTST, the proper design and pressure relationships required are as follows:

  1. Accurate and calibrated pressure gauges. There is no need for an automated system or a written program.
  2. Proper pressure relationship. The pressure on the product side of the heating section must be higher than the pressure on the heating medium side of the heating section during forward flow, divert flow and shutdown conditions.
  3. The pressure relationship between the product and the heating medium must be monitored and recorded daily.

The above requirements are currently in place and the Dairy Establishment Inspection Manual (DEIM) will be updated to clarify this position on the next revision.

Jennifer Miner
Recommended by: Program Chief
Wassim El-Khoury
Approved by: National Manager
Date modified: