To Pasteurize or Not

Contributor: Hannah Brooks. Lesson ID: 12164

Can you guess how pasteurize got its name? How can something that is meant to keep you healthy be bad for you? Learn all the pros and cons of this method to clean food!


Life Science

learning style
personality style
Lion, Otter
Grade Level
Middle School (6-8)
Lesson Type
Dig Deeper

Lesson Plan - Get It!

Audio: Image - Button Play
Image - Lession Started Image - Button Start
  • How often do you clean your room?
  • Did you know that milk and dairy products go through a cleaning process to make them safer for humans?
  • What kind of milk do you use when you make a bowl of cereal?
  • Do you use a clean bowl and spoon?

If you use traditional cow milk, it has gone through a process called pasteurization, where harmful bacteria are killed through heating the liquid.

  • Why might milk be considered dirty?

Well, it is collected from a cow using either manpower or a machine, and this creates a possibility of contamination from bacteria living on the cow's skin or udder. To protect consumers from these microorganisms, many farms and processors use pasteurization to ensure the product is safe to drink!

You are going to learn about the actual processes. Pasteurization was discovered by Louis Pasteur in the 1860s as he was heating alcoholic beverages to eliminate bacteria that caused the drinks to spoil.

Today, there are three main kinds of pasteurization: flash, steam, and irradiation.

In flash pasteurization, the liquids are exposed to short periods of very high heat, up to 161 degrees Fahrenheit. This process kills most of the microorganisms without losing the original color of the liquid.

Steam pasteurization involves exposing the product, usually solids, to high pressure steam for a few seconds in order to kill living organisms on the surface.

Finally, irradiation pasteurization applies radioactive waves in small quantities to liquid and solid food products to eliminate any living bacteria. It does not make the products radioactive, so it is considered safe for human consumption.

Learn about different foods that go through the pasteurization process!

First, create a chart similar to this one onto a sheet of paper:

  Food Product  Pasteurization Process  Final Packaging
  juice concentrate    
  ice cream    


Then, use these resources to complete your chart:

Wow! So many of our foods use pasteurization to become safe for consumption!

So it sounds like the process of pasteurization to purify products is a no-brainer! It helps keep us safe from microorganisms and bacteria, but it can also pull nutrients and flavors out of food during the cleansing process.

In the Got It? section, you will build an argument using online research sources about the use of pasteurization in cheese production.

Image - Button Next