To: All Regional Food and Drug Directors
Attn: Regional Milk Specialists
From: Milk Safety Branch (HFF-346)
Subject: Digital Reference Thermometer (DRT) Mfg. by Anderson Instrument Co.
The above subject dairy equipment has been reviewed by Milk Safety Branch and Food Engineering Branch and found to comply with the applicable criteria to permit the use of the DRT as a replacement for the mercury actuated indicating thermometer required on holding tubes of HTST or HHST pasteurization systems.
The DRT has been tested by food Engineering Branch and found to be equally failsafe, accurate, reliable and meet the scale and thermometric response specifications of Appendix H of the Grade 'A' Pasteurized Milk Ordinance.
The DRT provides for failsafe operation by utilizing two separate resistance temperature devices (RTDSs). If the two RTDs read more than 0.5oF difference from one another the display blanks making it impossible for the operator to observe the temperature. This condition, as with a broken mercury actuated thermometer, would require the immediate replacement of the thermometer.
The conventional test of Appendix I for Indicating Thermometers (Test 1 and 7) should be run on the DRT. The instruction manual supplied with the DRT provides additional guidelines for performing these tests. After testing by the regulatory agency they should apply their conventional seal to the cover and to the head of the dual element temperature sensor to assure that the sensor has not been replaced which would entail retesting of the instrument.
Descriptive literature for the dairy equipment is included for your files. States desiring further information or copies of the literature may contact:
Anderson Instrument Co.
RR 1, Auriesville Road
Fultonville, NY 12072
Sufficient copies of this memorandum are enclosed for distribution to state milk control agencies and state milk sanitation rating officers in your region/district.
FDA's review of this dairy equipment and our finding that they comply with the applicable construction criteria of the Grade "A" Pasteurized Milk Ordinance does not constitute agency endorsement or approval of the dairy equipment and any representation on a label or in any printed literature that they are "FDA approved" would be false.
Robert L. Sanders
Milk Safety Br.