Last week we talked about how milk is homogenized and what that means for its nutritional value. This week, we talk about a related issue: how milk is pasteurized and why!
Food Science: What is Pasteurization?
The process of heating milk to kill pathogens and prevent spoilage was developed back in the 1860's, but it didn't become standard until dairy farming became industrialized in the 1900's. As milk started being collected and distributed by centralized companies, the risk of contamination grew and pasteurization became a necessity.
There are actually three different methods of pasteurization:
1. The milk is heated to 145-degrees Fahrenheit for 30-35 minutes. This is called "batch" pasteurization and is employed when working with a relatively small amount of milk (up to a few hundred gallons). This has a minimal affect on the milk's flavor and is the method most often used for small-scale cheese production.
2. Larger industrial operations use the "high temperature, short time" (HTST) method, which involves pumping milk through a heat exchanger at a minimum of 162-degrees Fahrenheit for 15 seconds. This significantly alters the flavor of the milk, producing a cooked flavor as compared to raw or batch-pasteurized milk. The majority of milk bought at a commercial grocery store will be HTST pasteurized.
3. Finally, milk can be "ultra-high temperature" (UHT) pasteurized. UHT milk is heated to between 265- and 300-degrees Fahrenheit for 1-3 seconds. This milk has a noticeable cooked flavor - even to our modern palates - and can be stored unrefrigerated for several months.
It's unclear exactly what side-effects pasteurization has on the nutritional value of milk. While it's good that harmful pathogens are destroyed through pasteurization, it's also possible that beneficial enzymes and proteins are being destroyed in the process. Many folks believe that the nutritional benefit of raw milk outweighs any risk from drinking it unpasteurized.
As we mentioned last week, homogenization and pasteurization aren't necessarily two sides of the same coin. The problem is that without pasteurization, active enzymes in homogenized milk will attack the fat globules, which are made unprotected during the homogenization process. This produces off-flavors and rancidity. Therefore, homogenized milk needs to be pasteurized, but milk can be pasteurized without being homogenized.
Raw milk or pasteurized - where do you stand?
Related: Good Question: How Long Can I Leave Butter Out?
(Image: Flickr member Adam Chamness licensed under Creative Commons)
Tags
Food Science, Dairy Products, Ingredients - Pantry, dairy, milk, pasteurization, pasteurizedRelated Links
- Tip: How to Choose Decaf Coffee
- Brewing Beer at Home: The Wort and First Fermentation
Beer Sessions - Flickr Find: Chewy Turkish Ice Cream!
- How Color Affects Your Perception Of Food
- Food Science: Why Did My Sauce Break?
Share
Comments (5)
Weekly Email
Top Posts
Top Recipes
- Weeknight Dinner: Quick Udon Noodle Soup
- Appetizer Recipe: Bacon-Wrapped Potato Bites with Spicy Sour Cream Dipping Sauce
- Lobster to Sweet & Sour: How To Make 6 Stir-Fry Sauces
- Recipe: Baked Persimmons
- DIY Recipe: Pumpkin Spice Latte (Just Like Starbucks!)
Top Tours
- Daniel's Cure-Inspired Project
- Tamar's Labor of Love Renovation
- Kitchen Gallery: White, Bright, and Clean
- Jean Greenfield's Kitchen And Garden In San Anselmo
- Kitchen Spotlight: San Francisco Sleek Yet Vintage Re-Do
© 2009 Apartment Therapy
Bovine tuberculosis in the past has been a big problem with unpasteurized milk. It is carried in milk and is infectious to humans.
In fact it is illegal in many places (at least it is where i live) to sell unpasteurized milk for drinking purposes. Most hippy markets will sell you "bathing milk" though and give you a disclaimer that its not for drinking while winking at you.
Really it is only heating milk and potentially protects you from disease so personally I'm not interested in raw milk.
view alicee's profile
We only drink raw milk purchased from a small local farm whom has never had a single case of bovide tuberculosis. They have independent testing done to confirm that their milk is disease free. We have two shares of a cow and that is how we get around the law in Tennessee where it is illegal to sell raw milk for human consumption.
view sar3j's profile
I think that on most developed countries, drinking raw milk from a certified farm wouldn't be a big risk. But pasteurization surely was a great advance - we live 80 years now instead of 40 because of that too :).
Where i live it's rare to find raw milk .
view LiaMatos's profile
I prefer non-pastuerized. I am lactose-intolerant and someone suggested I try "real" milk. It made an immediate difference in my life. I can now actually drink a glass of milk and not have to worry about you know what, ha!
I think pasteurization was needed back in the day because there weren't enough regulations in place and it was common to have unsanitary conditions. Truely, it is outdated now that our society has advanced to one that uderstands the importance of hygeine, especially as it relates to food sources. You can get sick from paseurized milk just as easily as un pasteurized. That is why it is important to know where your food comes from and that it is a farm that hasn't had citations.
view christy5150's profile
Pasteurization was developed so that humans could drink sub-standard quality milk, that otherwise would have been unfit for consumption. It's a relatively new practice. Humans were drinking unpasteurized milk for hundreds of years with no problems. Factory farming is the only reason bovine diseases are so common and prevalent.
Like Christy, I too thought I was lactose intolerant - not so! I was only intolerant to dairy because all the lactase - needed to process the lactose - is destroyed in the pasteurization of milk.
Needless to say, I'm a raw milk lifer.
view Risa Kate's profile