Extension News

Use a Thermometer When Grilling Burgers

Meat Thermometer


AMES, Iowa--Is there a thermometer in your burger? Iowa State University Food Safety Extension Specialist Sam Beattie hopes so.


"Just as home-grilled burgers are a sure sign of summer celebrations, a thermometer is the one sure way to be certain those burgers are fully cooked," Beattie said. "The very serious E. coli illness can result from eating under-cooked burgers."


To take the temperature of a hamburger, Beattie recommends holding the patty with tongs and pushing the point of the thermometer into the side of the burger going toward the center. The thermometer should hit the thickest part of the hamburger and read 160°F.


"This temperature kills the bacterium E. coli O157:H7 and other illness causing bacteria," Beattie said. "Children are especially sensitive to the E. coli bacterium."


If you do not have a thermometer, Beattie advises cooking the meat until it is brown and the juices are clear without any bloodiness or cloudiness. "However, it cannot be guaranteed that the product is hot enough without a thermometer," Beattie said.


Besides using a thermometer, Beattie offers these additional food safety tips: keep it cold, keep it clean, and chill it quickly.


Keep it cold -- When picnicking and eating outdoors during the heat of the summer, food can warm up and get to the temperatures that allow illness causing bacteria to grow the fastest.


"Food packed on ice or kept in the refrigerator until just before serving will help prevent illness," Beattie said.  "The two hour rule is the key -- you have two hours at room temperature for perishable foods. On very hot days, however, food warms more quickly and a more realistically safe time is about one hour. Salads have been shown to be a significant cause of foodborne illness when warm. You can keep salads cold longer by using two bowls - the one with the salad nested in a larger one with ice."


Meats should be thawed in the home refrigerator before taken to the picnic and should be kept on ice until just before cooking. If marinating the meat, it should still be placed in the refrigerator. Once the meat is removed, the marinade should be either discarded or, if used as a sauce, brought to a rapid boil to kill the bacteria.


Keep it clean. "One of the leading mistakes that we make is to use the same platter for raw meat as the grilled meat," Beattie said. "That habit lets bacteria from the juices of the raw meat contaminate the cooked meat." Washing platters and cutting boards with hot soapy water and then rinsing with hot water will remove and kill the illness-causing bacteria. Also, meat stored on ice will contaminate the ice, so if possible use very heavy plastic bags or better yet a separate ice chest for the meat."


"And don't forget to wash your hands often and thoroughly," Beattie said. "They easily become contaminated with a variety of illness-causing organisms."


Chill it quickly. Picnics are a time of leisure but only after the food has been put away, reminds Beattie. "Leaving food out for longer than one or two hours will cause it to warm up to temperatures that allow illness-causing bacteria to grow rapidly. Once again the two hour or one hour rule applies. Put the leftovers back on ice; or discard them if you can't keep them cold."




Contacts :

Sam Beattie, PhD, Food Science and Human Nutrition, (515) 294-3357, beatties@iastate.edu

Diane Nelson, Continuing Education and Communication Services, (515) 294-3178, dinelson@iastate.edu

A photo, suitable for publication, is available below in color and in black and white.

Meat thermometer (color)

Meat thermometer (black and white)