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Published July 03, 2009, 12:00 AM

Thermometer ensures meat is fully cooked

“Mom, look at this hamburger. It’s a little pink inside,” my 14-year-old son said as he pointed his hamburger in my direction at a restaurant. I looked at the remaining bite of hamburger. He studied my expression. “Am I going to get really sick?” he asked.

By: Julie Garden-Robinson, INFORUM

“Mom, look at this hamburger. It’s a little pink inside,” my 14-year-old son said as he pointed his hamburger in my direction at a restaurant.

I looked at the remaining bite of hamburger. He studied my expression.

“Am I going to get really sick?” he asked.

“You can’t tell if a burger is done by looking at its color. A brown burger isn’t necessarily fully cooked, and a pinkish burger isn’t necessarily undercooked,” I said.

“Just how sick am I going to get?” he asked, pressing for details.

“You’re probably going to be just fine because the restaurant should measure the internal temperature of the burgers,” I said.

I should have specified a temperature of 160 degrees, I thought to myself. Then they would be sure to measure it.

“Why can you have pink steak and not worry about it?” my 11-year-old daughter asked.

My lunchtime was becoming a food safety lecture, but this was a teachable moment.

“On steaks and roasts, the bacteria would be on the outside of the meat. During cooking, the bacteria on the outside would be inactivated by the heat right away. When meat is ground to make burgers, the bacteria is spread throughout the meat. That’s why we use a food thermometer all the time,” I responded.

We enjoyed the rest of our lunch. My son did not get sick, much to his relief.

Many types of bacteria, including salmonella, E. coli O157:H7 and many others, can be present in meat and other foods. E. coli O157:H7 has garnered the most attention because of deadly outbreaks linked to undercooked meat and contaminated produce.

The toxin associated with E. coli O157:H7 can lead to hemolytic uremic syndrome, which in turn can result in kidney failure, brain damage, strokes and seizures.

Young children, the elderly and immune-compromised individuals are among those most vulnerable to getting sick.

Meat color in the raw and cooked state has been studied by many researchers.

Consumers prefer bright red meat in the meat case at grocery stores. Raw ground meat undergoes natural color changes as a result of exposure to oxygen.

You may note that the meat on the outside of a package of fresh ground beef may be redder than the meat inside. When meat is red, myoglobin (a pigment) is in its most oxygenated form, called oxymyoglobin. When the pigment is not exposed to air, the pigment converts to another form, metmyoglobin, which is grayish brown.

Meat that starts out slightly brown may look “done” sooner.

The color that meat turns during cooking can vary depending on the age of the animal, whether the meat was frozen previously and the length of the thawing time.

Because of these issues, food safety educators have stepped up their efforts to teach and encourage people to use food thermometers. Remember this slogan from Thermy, the U.S. Department of Agriculture’s mascot: “It’s Safe to Bite When the Temperature Is Right.”

For safety, don’t go by visual cues. Cook hamburgers to a minimum internal temperature of 160 degrees. Be sure to clean your food thermometer thoroughly, too.

Here’s a tasty recipe with food safety instructions from the USDA’s Food Safety and Inspection Service:


Fiesta Burgers

1½ pounds lean ground beef

¼ cup onion, chopped

2 tbsp. red bell pepper, finely chopped

3 tbsp. picante sauce or salsa

2 tsp. prepared Dijon-style mustard

1 tbsp. prepared horseradish (optional) salt and pepper to taste

4 sesame seed hamburger buns leaf lettuce and sliced tomatoes

Wash hands with soap and warm water for 20 seconds before handling the meat. In a bowl, mix the ground beef with onion, red pepper, picante sauce or salsa, mustard, horseradish (if desired), salt and pepper. Form into four burgers, each about ¾-inch thick. Wash hands with soap and warm water for 20 seconds after handling the meat.

Using utensils, place burgers on a grill that has reached medium-high heat. Check each burger with a food thermometer after approximately 10 to 15 minutes. Turn burgers as needed. A hamburger is done when it reaches 160 degrees. Clean the thermometer between uses with hot, soapy water. Place burgers on buns and top with condiments and garnishes of choice. After measuring the final temperature, remember to clean the food thermometer with hot, soapy water.

Makes four servings. Each serving has 430 calories, 19 grams (g) of fat, 25 g of carbohydrate, 460 milligrams of sodium and 25 percent of the daily value for iron.


Julie Garden-Robinson, Ph.D., L.R.D., is a North Dakota State University Extension Service food and nutrition specialist and associate professor in the Department of Health, Nutrition and Exercise Sciences.

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