ADVANCEMENT OF THE PRACTICE
Open Access
THE PRACTITIONER’S TOOL KIT
A Reintroduction to the Infrared Thermometer
James J. Balsamo, Jr., MS, MPH, MHA, RS, CP-FS, CSP, CHMM, DEAAS Nancy Pees Coleman, MPH, PhD, RPS, RPES, DAAS
Brian Collins, MS, REHS, DLAAS Gary P. Noonan, CAPT (Retired), MPA, RS/REHS, DEAAS Robert W. Powitz, MPH, PhD, RS, CP-FS, DABFET, DLAAS Vincent J. Radke, MPH, RS, CP-FS, CPH, DLAAS Charles D. Treser, MPH, DEAAS
Editor’s Note: The National Environmental Health Association (NEHA) strives to provide relevant and useful information for environmental health practitioners. In a recent membership survey, we heard your request for information in the Journal that is more applicable to your daily work. We listened and are pleased to feature this column from a cadre of environmental health luminaries with over 300 years of combined experience in the environmental health field. This group will share their tricks of the trade to help you create a tool kit of resources for your daily work. The conclusions of this column are those of the authors and do not necessarily represent the ocial position of NEHA, nor does it imply endorsement of any products, services, or resources mentioned.
thermometer and ensure that the sensor is clean and free of spatter. 2.IR thermometers do not draw heat away from the food being measured as can con- tact thermometers. When used correctly, the IR thermometer improves the repeat- ability of temperature measurements. We are therefore able to screen (screen being the operative word) large lots and areas for temperature discrepancies. And once base- line conditions are established, the ability to verify any o-specification findings is enhanced with smaller, statistically signifi- cant lot sizes using our validated electronic probe thermometers. In short, new IR thermometers provided greater versatility, while significantly reduc- ing both error and risk of cross-contamina- tion mediated by inspectors. With ease of use, however, we soon also learned of its ease of abuse. Instead of being used as a screening tool, the IR thermome- ter took on the role of an enforcement tool, which resulted in numerous horror stories of retail food operations discarding perfectly good food or ordering unnecessary repairs to properly functioning refrigeration units when an “o” temperature was detected. Unfortu- nately, these problems are ongoing and serve no purpose in protecting the public.
We just learned that the standard for infrared (IR) thermometers is up for republication (UL 2333: Standard for Infrared Thermometers). Several of us initially drafted the Use and Care Instruction section, which became Annex B in the first edition of the standard and we thought this column would be an opportune place to review the science, capabilities, and nuances of IR thermometers to ensure that this essential tool is used correctly in the field. We purchased our first unit in 1981. It was a large, cumbersome, heavy, and expensive analog tube designed to read temperatures at the high end of the Fahrenheit scale (>200 °F). We used this unit to find hot and cold spots in large baking ovens, locate unmarked hot water pipes, identify worn bearings on HVAC systems, and determine surface tem- perature in any inaccessible place, except for food. In the early 1990s, IR manufacturers introduced an inexpensive, lightweight unit to the food industry. This new instrument had a temperature measurement range from approximately 0–525 °F (-18–275 °C), with variation and a minimum accuracy of 4 °F (2.2 °C), making it ideal for use as a screen- ing device. Since then, the IR thermometer
has significantly changed our entire industry and application. These newly designed IR thermometers were ideal for regulatory practice. They allowed temperature screening where foods were too hot to touch or dicult to reach, where the food was moving too fast on a con- veyor cooker, and where foods were possibly subjected to unusual environmental tempera- ture influences. IR thermometers also allowed us to easily scan cooling systems, refrigerated display cases, truck interiors, and cold and dry storage areas for temperature anomalies. With the new design, we were able to dem- onstrate improved product quality, increased productivity, and reduced downtime by rap- idly finding and fixing problems that might aect food safety. Not bad for a small and relatively inexpensive field instrument. The IR thermometer has two features that make it ideal for quality control and regula- tory screening: 1.IR thermometers do not come into con- tact with food and do not require clean- ing and sanitization between applications. Even so, it is a good sanitary practice to periodically wipe down the exterior of the
Understanding the Infrared Thermometer
Understanding the operating principles of an IR thermometer helps us to better utilize the capabilities and limitations of the unit in our work environment. IR thermometers measure light. We can see wavelengths from about 0.4–0.7 microns
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