Science and Our Food Supply: Investigating Food Safety from Farm to Table

60

MIDDLE LEVEL

SAFETY 

FIRST

FOOD SAFETY CONNECTION

 

COOKING RIGHT

The Science of Cooking a Hamburger

The teacher will demonstrate cooking hamburgers to different temperatures. Students 

will analyze Petri dishes inoculated with hamburger and observe the amount of 

bacteria at each temperature. They will also learn that cooking hamburgers to the 

recommended temperature of 160° F (71° C) will kill pathogenic bacteria. Hamburger 

is used for this cooking lab because it’s a food that students are familiar with and may 

be cooking at home. 

•

  It’s particularly important to cook ground meats such as 

hamburger thoroughly, because there’s a greater chance 

for bacterial contamination with ground meat than with 

whole cuts. The bacteria start out on the outside of the 

meat. When the meat is ground, any bacteria that were 

originally on the outside can be distributed throughout 

the hamburger. In addition, when making patties, 

harmful bacteria from hands, utensils, and surfaces can 

be transferred to the inside of the hamburger patty. 

It’s important, therefore, to make sure that the internal 

temperature of the hamburger has reached a safe internal 

temperature (160° F [71° C]) to kill foodborne pathogens 

that may be present.

•

  An “instant-read” dial food thermometer with a probe 

in the tip is best for checking the proper temperature of 

hamburgers. The probe should be inserted in the side 

of the burger, so the entire sensing area (usually 2 to 3 

inches [5 to 8 cm]) is positioned into the center of the 

burger.

•

  It may not always be possible to check the hamburger 

with a thermometer – for example, when you’re eating in 

a restaurant. In this case, the safest thing is to ask for the 

hamburger to be cooked to a temperature of 160° F. Send 

it back if it’s pink in the middle, although keep in mind 

that the color of the meat is not an accurate indicator of 

whether it reached a safe internal temperature.

TIME  

One 45-minute class period to conduct the lab. Observe results at the 

beginning of the next class period.

Hamburgers are a staple in the diet of many teenagers. Knowing how to cook them 

to a safe internal temperature to prevent foodborne illness is important. 

LAB AT A GLANCE

•

 DO NOT EAT OR TASTE ANY OF THE 

HAMBURGER USED IN THE LABS.

•

 Your hands and lab surfaces may be 

contaminated after being in contact 

with raw meat. 

– Disinfect any surfaces that come 

in contact with the raw meat (see 

page 8.)

– Thoroughly wash your hands before 

and after handling the raw meat. 

•

 Wear safety gloves and lab aprons 

when handling the meat, as well as 

safety goggles when cooking meat. 

•

 Beware of hot surfaces. Use a thermal 

hot pad when handling skillets, hot 

plates, etc.

•

 Thoroughly wash all thermometers in 

between uses with soap and water, 

or clean with alcohol pads.

•

 Properly dispose of all raw meat.

•

 Seal all dishes with Parafilm. Never 

open a Petri dish with organisms in it; 

some organisms could be dangerous 

pathogens.