Reply
Thread Tools Display Modes
#1
Old 11-13-2006, 06:19 PM
Charter Member
Join Date: Mar 2002
Posts: 1,792
Pasteurized Milk Spoiling.

Why does pasteurized milk left in a sealed container still spoil? I mean, what then is the purpose of the pasteurization? And is pasteurization different from canning?

Thank you in advance to all who reply
__________________
"Love takes no less than everything." (from "Love Is", a duet by Vanessa Williams and Brian McKnight)
#2
Old 11-13-2006, 06:31 PM
Guest
Join Date: Aug 2003
Location: was Montreal, now MD
Posts: 7,116
From the Wiki page on Pasteurization:


Quote:
Unlike sterilization, pasteurization is not intended to kill all micro-organisms (pathenogenic) in the food. Instead, pasteurization aims to achieve a "log reduction" in the number of viable organisms, reducing their number so they are unlikely to cause disease (assuming the pasteurized product is refrigerated and consumed before its expiration date). Commercial scale sterilization of food is not common, because it adversely affects the taste and quality of the product.
Basically, not all the organisms are killed. Milk is something you keep in the fridge, and something you're supposed to consume fairly quickly after it's purchased, so there isn't much chance for those few bacteria left behind to multiply and do much damage.

Leave them in there long enough, though, and they will grow and take over, spoiling the milk. Milk that stays in the fridge the whole time will take a lot longer to spoil because the bacteria are slowed down by the temperature, but it will still happen eventually.
#3
Old 11-13-2006, 10:00 PM
Guest
Join Date: Mar 2001
Location: Arlington, TX
Posts: 3,264
Alas, pasteurization does kill the microorganisms that cause milk to go sour, which is a relatively benign process. It's the pasteurization trade-off--drastically decreased likelihood of being sickened or killed by your milk, in exchange for increased difficulty in doing other neat things with it. If you want to make sour milk or cream, buttermilk, yogurt, cheese, etc. from pasteurized milk, you need to 'seed' it with a culture of the appropriate bacteria or mold. That's the 'cultured' in the 'cultured sour cream' you find at the grocery store.
__________________
-Christian
"You won't like me when I'm angry. Because I always back up my rage with facts and documented sources." -- The Credible Hulk
#4
Old 11-13-2006, 10:36 PM
ftg ftg is offline
Guest
Join Date: Feb 2001
Location: Not the PNW :-(
Posts: 16,846
OTOH, UHT milk is widely available and lasts quite a while unrefrigerated.

http://en.wikipedia.org/wiki/UHT
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 02:48 PM.

Send questions for Cecil Adams to: [email protected]

Send comments about this website to:

Terms of Use / Privacy Policy

Advertise on the Straight Dope!
(Your direct line to thousands of the smartest, hippest people on the planet, plus a few total dipsticks.)

Copyright 2018 STM Reader, LLC.

Copyright © 2017
Best Topics: shriners secret password animaniacs elements groundhog smoke bombs latin for existing gassho meaning pronounce thuy mayor shinn cardassian names civet pet dremel for feet tall handlebars motorcycle new jersey car dealerships open sunday dr. pepper knock offs are any slaves still alive dope names for tumblr can you become immune to cyanide job application contact current employer st augustine travel quote why do soldiers wear helmets difference between multimeter and voltmeter ace key copy price what does trim mean on a car