Development of a Testing Protocol for Electronic Sensors Used as Temperature References

The mercury-in-glass thermometer (MIG) is currently the temperature reference for commercially sterilized low-acid canned foods (LACF). Since the adoption of the MIG as the reference temperature device for LACF processes a number of devices have been developed that appear to be as durable and as accurate. These devices have not been examined to the point where it can be determined if they are acceptable as alternate temperature measuring devices (ATMD) for LACF processes.
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In the first year of this project an ATMD was installed on three commercial retorts and the pilot plant unit at the NCFST, and a survey of current practices and uses of, the MIG in low-acid canned food processing facilities was initiated. During the second and third year, the ATMD was tested, both in the pilot plant and in commercial settings, and a draft testing protocol for the drift test was developed from the data collected. To test the drift test protocol a second ATMD was installed at two commercial settings.Environmental and electromagnetic interference (EMI) tests were conducted on both devices. A draft protocol for drift, EMI, and environmental testing were completed. Environmental testing of the ATMDs indicated that they should function as intended in a harsh environment such as in a LACF facility.