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magine the excuses that dental hygienists hear from patients who don’t floss as often as they should: I don’t have any floss. I’m not sure how to do it correctly. I just flossed yesterday. I’ll do it tomorrow. I’m too busy. These excuses tend to sound an awful lot like the ones that might be heard when attempting to defer
another important health practice: taking and recording food temperatures in foodservice kitchens.
Take Your Temperature Ensure that taking and recording food temps never becomes an overlooked safety step. By Patrick White
“We’ve done quite a bit of research in this area. We’ve gone out into many foodservice operations—not just schools— and observed safe food-handling practices, part of which is taking and recording temperatures,” says Susan Arendt, associate professor of hospitality management at Iowa State University and part of its Extension’s SafeFood Research Team. “While taking and recording temperatures should be a common practice, we’ve certainly found that’s not always the case.” Arendt and her fellow researchers have tried to determine why foodservice employees aren’t taking and recording temperatures as often as they should. “We’ve tried to identify those barriers,” she explains. “We run into things like: ‘There aren’t enough thermometers in the kitchen,’ or ‘The thermometers aren’t readily available’ and ‘No one has trained employees on how to appropriately use the thermometer.’ Of course, one big issue with foodservice employees is not knowing how to calibrate thermometers. And we always hear about how everyone is so busy trying to get the food out to the kids that it becomes difficult to get temperatures taken and recorded.” Dissecting these rationalizations can help school nutrition directors and managers put together a plan for promoting more regular and effective monitoring of food temperatures.
The Basics The first step is to ensure that thermometers are available for all kitchen staff. “Some facilities are really good about that. Everyone walks around with a thermometer in their pocket,” says Arendt, while acknowledging that “sometimes that approach is more difficult in schools, where fiscal resources are often tight.” Even in 60
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cases where each employee may not have their own thermometer, managers can place thermometers in key areas throughout the kitchen—making sure they are always kept in those specific locations, advises Arendt. It’s also important to devote adequate time to train employees in the proper use of thermometers, emphasizes Arendt. “This includes where and how to take the temperatures,” she says. Different types of foods—and different types of thermometers—will require diverse approaches, so training must take such variables into account. Training also should include information on properly cleaning and sanitizing food thermometers; this typically involves the use of alcohol swabs, which should be stocked and stored in convenient places to allow employees to take a food’s temperature, sanitize the thermometer, record the results and get on with their other duties. Beyond training, Arendt says that oversight by managers is essential in driving home to staff the importance of taking and recording temperatures. “Managers need to encourage employees, and then hold employees accountable for recording temperatures,” she asserts, noting that if staffers don’t see the manager placing a high level of importance on the taking and recording of food temperatures, these steps are much more likely to be skipped. “The manager really needs to be the role model to the employees when it comes to food safety practices and creating a food safety culture.”
Take Time to Calibrate “There are several different kinds of food thermometers— some can be used for surface temperatures; others for internal temperatures,” says Arendt. (See the boxes throughout this article for more
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detailed information on options.) Infrared and laser thermometers are making their way into some school kitchens, and these are quick and easy to both use and keep clean, she observes. But they’re also considerably more expensive. “The bimetallic stem thermometers are still the ones that we see most commonly used in school kitchens,” states Arendt, noting that this type of thermometer works well when used properly and is relatively inexpensive. “And they’re easy to carry around; some infrared thermometers, on the other hand, can be quite large, so to stick one in your pocket and carry it around with you isn’t always easy,” she adds. One concern about conventional bimetallic stem thermometers is that they need to be calibrated regularly, which doesn’t always happen. “Sometimes, there’s no policy or procedure about when thermometers should be calibrated, or employees don’t know how to calibrate,” explains Arendt. For example, on the ubiquitous bimetallic coil thermometers, there typically is a nut on the bottom that must be twisted to calibrate the thermometer.
Digital Food Thermometers Thermocouple f all food thermometers, thermocouple thermometers reach and display the final temperature in the fastest time—within 2 to 5 seconds. The temperature is indicated on a digital display. A thermocouple measures temperature at the junction of two fine wires located in the tip of the probe. Since thermocouple thermometers respond so rapidly, the temperature can be quickly checked in a number of locations on the food to ensure that it is thoroughly cooked. This is especially useful for cooking large foods, such as roasts or turkeys, when checking the temperature in more than one place is advised. The thin probe of the thermocouple also enables it to accurately read the temperature of thin foods, such as hamburger patties, pork chops and chicken breasts.
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In other cases, kitchen team members simply don’t want to take the time to complete the calibration practice, as it involves either preparing an ice bath or boiling water. The National Food Service Management Institute’s (NFSMI) Thermometer Information Resource recommends calibrating bimetallic and digital thermometers at least once a week. NFSMI advises that the ice water method is preferable (pending specific manufacturer recommendations). Employees should follow these basic steps: 1. Fill a 2-qt. container with ice. 2. Add water so liquid comes within 1 in. of top of the container. 3. Stir the mixture well. 4. Let it sit for one minute. 5. Place the thermometer in the container so that the sensing area of the stem or probe is completely submerged (over the dimple). 6. Do NOT let the thermometer stem/ probe touch the sides or bottom of the container. 7. Let the thermometer stay in the ice water for 30 seconds or until the dial stops moving.
Thermocouples are not designed to remain in the food while it’s cooking. They should be used near the end of the estimated cooking time to check for final cooking temperatures. Thermocouples can be calibrated for accuracy.
while it’s cooking. They should be used near the end of the estimated cooking time to check for final cooking temperatures. Not all thermistors can be calibrated; check the manufacturer’s instructions.
Thermistors hermistor-style food thermometers use a resistor (a ceramic semiconductor bonded in the tip with a temperature-sensitive epoxy) to measure temperature. The thickness of the probe is approximately 1⁄ 8 of an inch, and it takes roughly 10 seconds to register the temperature on the digital display. Since the semiconductor is in the tip, thermistors can measure temperature in thin foods, as well as thick foods. Because the center of a food is usually cooler than the outer surface, place the tip in the center of the thickest part of the food. Thermistors are not designed to remain in the food
Oven Cord Thermometers his type of food thermometer allows the cook to check the temperature of food in the oven without opening the oven door. A base unit with a digital screen is attached to a thermistor-type food thermometer probe by a long metal cord. The probe is inserted into the food, and the cord extends from the oven to the base unit. The thermometer is programmed for the desired temperature and beeps when it is reached. While designed for use in ovens, these thermometers also can be used to check foods cooking on the stove. Oven cord thermometers cannot be calibrated.
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Source: Partnership for Food Safety Education
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8. Place the calibration tool on the adjusting nut and rotate until the thermometer dial reads 32°F (while in ice water). 9. Some digital stemmed (thermistors) and thermocouples units have a reset button, which should be pushed. 10. Repeat the process with each thermometer in the kitchen. 11. Record the date and time that each thermometer was calibrated.
Recording Session Taking accurate food temperatures is important, but just as important is recording those temperatures, states Arendt: “We always say, ‘If it’s not documented, it’s not done.’ The logging is really the documentation. We never, never, never want this to happen, but if there was a suspected case of foodborne illness, those temperature logs are the documentation that the food was kept in the appropriate temperature zone.” Just as it’s important to stage thermometers throughout the kitchen, keeping log books in logical places can boost the chances they’ll be used. Temperatures can
Dial Food Thermometers
AdvancePierre Foods.....................................3 American Egg Board....................................29 Ardent Mills..................................................59 Bush Beans...................................................65 Cambro Manufacturing................................41 Campbell Soup Company......................36, 37 Cres Cor.......................................................51 Domino’s Pizza............................................ C2 E S Foods.....................................................67 Garden City Group (G.C.G.).........................40 General Mills Foodservice............................45 Harris School Solutions................................53 Horizon Software..........................................63 J.M. Smucker Company...............................31 Meals Plus....................................................30 Nutrislice......................................................33 PanSaver.......................................................32 Payless ShoeSource......................................61 Pilgrim’s Pride/Gold Kist Farms....................11 Pinnacle Foods Group..................................19 Pizza Hut...................................................... C3 Red Gold........................................................1 Robot Coupe................................................18 Ruiz Food Products......................................23 Sara Lee Foodservice...................................28 SNA–Emporium............................................71 Schwan’s Food Service............................ 7, C4 Sea Watch International...............................47 SunGold Foods–SunButter...........................21 Tree Top........................................................17 Tyson Foods.................................................27 Vulcan.......................................................5, 69
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Bimetallic coil Thermometers hese thermometers contain a coil in the probe made of two different metals that are bonded together. The two metals have different rates of expansion. The coil, which is connected to the temperature indicator, expands when heated. This food thermometer senses temperature from its tip and up the stem for 2 to 21⁄2 inches. “Oven-safe” bimetallic coil thermometers are designed to remain in the food while it is cooking in the oven, and are generally used for large items such as a roast or turkey. This type of food thermometer is convenient because it constantly displays the temperature of the food while it is cooking. However, if not left in the food while cooking, they can take as long as 1 to 2 minutes to register the correct temperature. In addition, there is concern that because heat conducts along the stem’s metal surface faster than through the food, the area of the food in contact with
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be recorded electronically in handheld units, but Arendt hasn’t personally seen these in use at the school kitchens she’s visited. “What we’re seeing, at least in schools, is that the preference is to still use the old tried-and-true documentation by pencil and paper,” she reports. The key is to make sure the logs are readily available. “For example, we often see logs posted to the refrigeration unit, for taking refrigerator temps, or on a clipboard located very close to the serving line for documenting those temps,” explains Arendt. “Keep those records in the same place all the time.” Whether the approach is hightech or low-tech, the most important thing is to ensure the process is convenient so that the job gets done. Just like flossing. SN Patrick White is a freelance writer in Middlesex, Vt., and a former assistant editor of this publication.
To Your Credit: For CEUs toward an SNA certificate, complete the “To Your Credit” test on page 52.
the thermometer tip will be hotter than the area a short distance to the side To remedy this, the temperature should be taken in a second and even third area, waiting at least 1 minute each time before reading the temperature. Some models of bimetallic coil thermometers can be calibrated. Check the manufacturer’s instructions. “Instant-read” bimetallic coil thermometers quickly measure the temperature of a food in about 15 to 20 seconds. They are not designed to remain in the food while it is cooking in the oven. For accurate temperature measurement, the probe of the bimetallic coil thermometer must be inserted the full length of the sensing area (usually 2 to 3 inches). If measuring the temperature of a thin food, such as a hamburger patty or boneless chicken breast, the probe should be inserted through the side of the food so that the entire sensing area is positioned through the center of the food. Some of these models can be calibrated. Check the manufacturer’s instructions.
