An activity you can use in the classroom
You can kill most of disease-producing bacteria in milk
by heating it to 143º F (62º C) and then keeping
it at that temperature for 30 minutes. This process
is called pasteurization. Today ?flash pasteurization?
is commonly used instead, in which milk is heated at
higher temperature of 160º F (71º C) and maintained
for 15 seconds. In this activity, you?ll explore
how the growth of additional bacteria after pasteurization
is slowed in colder temperatures. 
- two clear plastic cups
- pasteurized milk
- refrigerator
- On a Monday, pour a small amount of milk in each
of two cups.
- Place one cup in a warm area, such as on a sunny
windowsill.
- Place the other cup in a refrigerator.
- What do you think will happen to the milk in each
cup over the next week? Write your predictions on
theworksheet.
- Over the week, check both cups each day and write
your observations in the worksheet chart. At the end
of the week, answer the final worksheet question.
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