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

63

MIDDLE LEVEL

 MODULE 4:

 RETAIL AND HOME

COOKING RIGHT

The Science of Cooking a Hamburger

7. 

When the hamburger has reached 120° F (49° C), break 

it in half and demonstrate how to swab the inside. Ask: 

Why do you break it rather than cut it in this scientific 

test? (The knife might have bacteria on it and you might 

transfer that bacteria into the hamburger.) 

8. 

Have a volunteer swab inside the broken edge of the 

hamburger and inoculate the “120° F” dish. Seal the 

dish with Parafilm. 

9. 

Cook the two remaining hamburgers: one to 140° F 

(60° C) and the other to 160° F (71° C). Have volunteers 

inoculate the dishes after each hamburger has reached 

the desired temperature. Seal dishes with Parafilm. 

Place the inoculated Petri dishes in the incubator at  

95° F (35° C) for 1 to 2 days, or let them sit at room 

temperature for the appropriate amount of time.