Hamburger Safe Internal Cooking Temperature

Restaurant Ground Beef Handling and Cooking

EHS-Net Recommends

Restaurant management and food-safety programs should work to reduce practices that could lead to undercooking and cross contamination of raw ground beef. Efforts should focus on policies and training about

Measuring the final temperature of ground beef using a thermometer or using standard cooking methods that always cook ground beef to 155°F.
Preventing cross contamination by proper hand-washing and equipment cleaning.

Beef patties on a cutting board.

If irradiated ground beef becomes readily available, food safety programs may also wish to consider educating restaurant owners about it. The risk for foodborne illness from undercooking ground beef and from cross contamination with ground beef may be lower if restaurants use irradiated ground beef.

Why This Study Was Done

E. coli, a germ often found in raw ground beef, causes many foodborne illnesses each year. Hamburgers made from ground beef are often the source of these germs. These germs can make people sick if burgers are undercooked (not cooked to a high enough temperature to kill the germs). These germs can also make people sick if they get into other food or onto other surfaces (cross contamination).

We don't know much about how restaurants prepare and cook ground beef for hamburgers. If we know more about these practices, we can improve them and lessen the number of foodborne illnesses.

What the Study Described

We had two reasons to do this study. The first was to describe restaurant ground beef practices that could lead to

Undercooking of ground beef. We defined undercooking as cooking to less than 155°F because the U.S. Food and Drug Administration (FDA) Food Code says that restaurants should cook ground beef to 155°F for 15 seconds. We also looked at whether restaurants used a thermometer to check final temperatures of hamburgers. Using a thermometer helps ensure that ground beef is not undercooked.
Cross contaminating other foods from raw ground beef. This can happen when hands or equipment touch raw ground beef and then touch other food or kitchen equipment.

The second reason for this study was to describe how much managers knew about and used irradiated ground beef. Irradiated ground beef is raw beef that has been treated to get rid of E. coli germs. If restaurants use irradiated beef instead of untreated ground beef, people may be less likely to get sick from germs in undercooked ground beef or from cross contamination of germs from raw ground beef.

What the Study Found

EHS-Net found that many restaurants prepare and cook beef in ways that could lead to undercooking or cross contamination.

Ground beef cooking temperature
Eight in ten managers said their workers do not always take a final temperature of hamburgers with a thermometer.

Many managers said their workers always or often check if hamburgers are ready in ways other than using a thermometer. They check

the color of the hamburger.
how the hamburger looks.
how the hamburger feels.

About one in ten hamburgers were undercooked (cooked to less than 155°F).

Cooking of Ground Beef
The FDA Food Code says that restaurants should cook ground beef to 155°F for 15 seconds. But CDC and USDA say that consumers should cook ground beef to 160°F. The guidance for consumers is different because it is simpler to meet one standard (temperature) than two (temperature and time). Cooking ground beef to 160°F kills E. coli germs rapidly.

Cross contamination
In many restaurants, workers were seen preparing raw ground beef in a way that could lead to cross contamination. Workers

Did not wash their hands in between touching raw ground beef and touching other foods (six in ten restaurants).
Used the same utensil on raw ground beef and other foods without washing in between (one in three restaurants).
Used the same utensil on raw ground beef and cooked ground beef (without washing in between) (four in ten restaurants).
Wiped their hands on cloths/aprons after touching raw ground beef (4 in 10 restaurants).

In over half of restaurants, workers were seen doing two or more of these things that could lead to cross contamination.

Use of irradiated beef
At the time this study was done (2004), irradiated beef was just beginning to become available to restaurants and grocery stores in some parts of the country.

Only 2% of managers said their restaurants have used irradiated ground beef.
About one in three managers said they do not know what irradiated ground beef is.
Managers said they do not use irradiated ground beef because
- It isn't available.
- They didn't know it is available.
- It costs too much.

Cross contamination: spread of germs from one surface or food to another by contact.
E. coli: germ that cause foodborne illness.
Irradiated ground beef: ground beef that has been treated to kill germs in the beef.

This study was conducted by the Environmental Health Specialists Network (EHS-Net). EHS-Net is a federally funded collaboration of federal, state, and local environmental health specialists and epidemiologists working to better understand the environmental causes of foodborne illness.