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From: Food Quality & Safety magazine, December/January 2007

Infrared: An Effective HACCP Tool

Expanding IR Technology Use in Food Services has Included Steps to Educate Industry about the Breadth of the Technology

by Brian Stowell

The heat is definitely on for food service operators to reach and maintain tight food safety standards. HACCP programs are all about controlling and eliminating hazards, and food temperatures—when, where and how to take them safely—are at the heart of the program. Fortunately though, hot and cold temperature measurement has gotten easier, faster and safer over the last few years. Infrared technology, as well as more sophisticated infrared temperature measurement techniques, can make a big difference.

Don Niemeyer is a seasoned quality control consultant to the food industry based in Fayetteville, Pa., who recently evaluated several combination infrared (IR) and probe thermometers for a U.S. Military dining facility contractor, one of his largest clients. After rigorous testing, he highly recommended the technology to the Army, Air Force and Marine Corps for use in their dining facilities. He had a variety of reasons for doing so.

“I was particularly impressed with the accuracy and speed of the IR thermometers I tested,” he says. “They’re so easy to use especially for measuring both hot and cold food temperatures, as well as very hot items such as deep fry oils and grill surfaces.”

As most food service operators know, the FDA has established safe temperature zones for both hot and cold foods. The program requires that cold food be kept at 41 F (5 C) or below, while hot foods must be held at 135 F (57.2 C) or above to be safe. Food service staff also must monitor those food temperatures at regular intervals that range anywhere from one to four hours.

In the wake of recent outbreaks of foodborne illness and product recalls making headlines around the world, everyone in the food service industry is searching for ways to combat potential fallout. Using infrared—which can be 20 times faster than traditional probe measurements—has broadened the ability of food service operators to quickly and safely take temperatures in ways they never knew they could and more often than they ever dreamed possible.

There’s a good reason new temperature measurement tools and techniques are in the forefront of the battle to maintain strict food safety standards.

The CDC has identified inadequate and improper temperature measurement as the major contributing factor in a majority of foodborne illness outbreaks. Here is the list of temperature related functions they say are performed inadequately:

  • Cooling and Cold Holding Temperatures
  • Hot Holding Temperatures
  • Reheating
  • Cooking or Heating Processing

They add also that cross-contamination during the temperature measurement process is the culprit about 6 percent of the time.

While the reason food service operations fail to meet HACCP requirements do esvary, and include causes such as poor hygiene among staff, failure to properly take and record food temperature measurement is at the top of the list. Why is something that sounds so simple such a source of failure?

Taking both hot and cold temperatures has traditionally been a time consuming operation because the primary tool being used has been a probe thermometer. Compared to infrared, it’s slow. The user has to wait several minutes at each stop for a traditional probe thermometer to reach the actual temperature of each food item being measured. When there are many different items in a buffet, or a hot or cold serving line, that’s a lot of time.

Likewise, cross contamination is always a concern. As food service staff gets pressed for time, they can forget to clean and sanitize the probe after testing one item and before inserting it into the next food product.

What is Infrared?

Invisible to the human eye, IR radiation is part of the electromagnetic spectrum that includes radio waves, microwaves, visible light, ultraviolet, gamma, and x-rays. All objects emit energy somewhere within that range, and all objects warmer than absolute zero (zero degrees Kelvin); including food, naturally emit infrared energy. When food temperatures are being taken, IR thermometers capture and instantly measure that invisible infrared energy.

Speed and Safety

Noncontact IR thermometers are extremely fast and can produce instant readings. By comparison, traditional probe thermometers can take as long as two or three minutes to get the same readings. As a result, IR thermometers are major time and money-savers.

Moreover, IR thermometers can be used to safely measure food items without touching them. That greatly reduces cross-contamination, or even eliminates it if the proper temperature measurement techniques are strictly and properly practiced. IR thermometers can also be used to measure hot, hazardous, or hard-to-reach surfaces without damaging them or the user getting burned. That is particularly beneficial when food service workers are measuring temperatures of dangerous items such as hot fry oils and candy.

Measuring Surface Temperatures

While IR sounds like the perfect total temperature measurement solution, in most people’s minds it has always had one major drawback—it only measures surface temperatures. What about the internal temperature of items such as soup, salsa, and macaroni and cheese?

Typically, food service operators love the speed and convenience of IR but don’t fully embrace it because they need the safety of an internal temperature. But, as they learn more about how to use IR to its full potential, its perceived limitations begin to disappear.

Using IR with NSF Rules

Under National Science Foundation (NSF) rules 4 and 7, temperatures must be taken 1 inch below the surface of the food item. In most people’s minds, that rules out using IR. They believe they need a probe thermometer to reach that critical 1 inch below the surface. A probe thermometer is one way to get that 1-inch below the surface temperature, but IR can also be used to take that internal temperature. Here’s how:

To measure cold food lines, use the serving spoon to move the top of each food item aside 1 inch to reach the new food surface. Immediately scan within a half inch of the food item with the IR thermometer. If the item is in the safe zone (below 40° F (4.4° C)), move to the next item. If not, take appropriate action to ensure the food item’s safety.

Likewise, for hot foods, use a ladle to pull food up from 1 inch below the surface and shoot the IR thermometer in close—within a half inch of the newly uncovered surface to get an instant and accurate internal temperature. With this method, cross contamination concerns disappear because none of the food has been touched by the operator or the thermometer.

Range of Features

Expanding the use of IR technology in the food service industry has included working to educate the industry about the breadth of this technology. There are more and more IR products on the market including some that combine IR with a traditional probe thermometer. Some models have a built in timer with an alarm that sounds when the next line check is due, and HACCP lights that flash red when a food item is in the unsafe zone and green when it is okay to serve the food. In addition, some models come with full two-year warranties for normal use failure, including dropping and calibration. Some are also NSF approved.

Multiple Benefits

In his report to his military client, quality control consultant Niemeyer details all the advantages that IR offered during his evaluation, which included:

Response Time: Almost immediate, allowing user to complete and record line (holding) temperatures on HACCP risk management forms more rapidly, thereby greatly reducing interference with line servers.

Grill Surfaces: IR feature is extremely useful and easy—avoids having to reach around cooks to place surface thermometer on grill, records temperatures at two or more areas of the same grill instantly to check calibration and especially useful when products require different settings such as scrambled eggs cooking along side hash browns. Almost guarantees proper cooking procedure.

Ambient Temperatures: IR feature is very accurate and fast for use in walk-in refrigerators and freezers to quickly check various parts of the food storage units and temperatures of items within the freezers where probes are useless.

Testing Deep Fat Fry Oils: With IR feature, users can actually perform a test of how much temperatures dropped when product was placed into hot oil and record recovery times, a function nearly impossible with a probe thermometer.

On the model that offered the HACCP check, he notes that this special feature allowed him to instantly see when the product was within the safe or unsafe HACCP temperature danger zone (TDZ).

“This feature makes it simple for cooks to actually see when product is or is not in the proper temperature zone,” he writes.

Niemeyer also used the IR function to solve a problem he always had trying to perform sanitizing temperature tests at the exit end of mechanical dishwashing machines. The results were so positive, he bought one of the combination probe and IR model thermometers to use for the audits and evaluations he conducts for his clients.

In the past, he always had to stick a thermal-paper thermometer on a plate and run it through the machine. Unfortunately, the paper thermometer frequently washed off and he would be required to do another test. During his IR evaluations, he decided to try to test both the plates and pot and pan washing, and sanitizing temperatures as required by the National Restaurant Association’s Educational Foundation “ServSafe” sanitation training.

“I just ‘aimed’ the thermometer in the IR mode on the plates as they exited the machine to ensure their surface temperatures were at 160° (F) or higher,” Niemeyer explains. “Now, I do this test for free making the technology pay for itself in a short time.”

More Tips on Ways to Use IR

He explains that it’s important to understand all the benefits that IR technology has and how it can be used in any food service operation. Here’s how Niemeyer and others use IR to meet the challenges food service operations face every day:

Receiving: Use IR to shoot boxes coming off delivery trucks to determine transport conditions. Scan cold boxes to spot-check—warm boxes are a red flag— everything. Likewise shoot the outside of milk cartons, and if they’re 40° to 45° degrees, they’re good. A temperature any higher than that should be checked with a probe thermometer. Record temperatures on the supplier invoice.

Line Checks: Take a fast IR scan 1 inch below the food surface on all hot and cold line checks, as allowed by NSF 4 and 7 standards. HOT: Use your ladle or spoon to pull hot food up from 1 inch below the surface and shoot close inside serving piece. COLD: Likewise, push back food 1 inch with the serving spoon and shoot in a half inch.

Timer/Alarm: If your IR thermometer has an eight-hour adjustable countdown timer with an alarm, use it as a line check reminder. The timer will beep when it’s time to perform the next line check. After completing the line check, re-set the timer for next line check reminder.

Equipment Calibration: Instantly verify temperatures on grills, ovens, coolers, freezers etc. Check fry oil temperatures by using the basket to stir the fry oil and shoot from 3 inches away. Place a brick inside stainless steel ovens. After warm up, open the oven door and shoot the brick to check oven cavity temperature.

Coolers and Freezers: Enter freezer or cooler and immediately close the door. Scan products to determine cooler efficiency, especially when closed for an hour or more. Avoid defrost time. With the door closed, check ambient air temperature by waving a piece of paper in any section of the cooler or freezer for a few seconds. Shoot the paper with the IR thermometer and compare to the cooler or freezer’s thermostat.

Beverages Machines: Direct liquid into a black plastic spoon, and use the IR thermometer to shoot the beverage up close inside the spoon.

IR thermometers can bring great value to food service operations when they are used properly and efficiently. They’re easy to operate; most only require the push of a button and reading the display panel-effective, accurate and affordable. With all the benefits IR has to offer, it is only a matter of time until it becomes the breakthrough technology for the food service industry.

Brian Stowell manages the development of temperature and portable products for Fluke Corp. (Everett, Wash.). Reach him at 425-446-6286 or



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