If you’ve ever shopped for milk, you’ve no doubt noticed what our questioner
has: While regular milk expires within about a week or sooner, organic milk
lasts much longer—as long as a month.
So what is it about organic milk that makes it stay fresh so long?
Actually, it turns out that it has nothing to do with the milk being
organic. All "organic" means is that the farm the milk comes from does not use
antibiotics to fight infections in cows or _hormones to stimulate more milk
production_
(http://www.sciam.com/article.cfm?id=milk-industry-gag-order-on-artificial-hormones-lifted) .
Organic milk lasts longer because producers use a different process to
preserve it. According to the Northeast Organic Dairy Producers Alliance, the milk
needs to stay fresh longer because organic products often have to travel
farther to reach store shelves since it is not produced throughout the country.
The process that gives the milk a longer shelf life is called ultrahigh
temperature (UHT) processing or treatment, in which milk is heated to 280 degrees
Fahrenheit (138 degrees Celsius) for two to four seconds, killing any
_bacteria_ (http://www.sciam.com/topic.cfm?id=bacteria) in it.
Compare that to pasteurization, the standard preservation process. There are
two types of pasteurization: "low temperature, long time," in which milk is
heated to 145 degrees F (63 degrees C) for at least 30 minutes*, or the more
common "high temperature, short time," in which milk is heated to roughly 160
degrees F (71 degrees C) for at least 15 seconds.
The different temperatures hint at why UHT-treated milk lasts longer:
Pasteurization doesn’t kill all bacteria in the milk, just enough so that you don't
get a disease with your milk mustache. UHT, on the other hand, kills
everything.
Retailers typically give pasteurized milk an expiration date of four to six
days. Ahead of that, however, was up to six days of processing and shipping,
so total shelf life after pasteurization is probably up to two weeks. Milk
that undergoes UHT doesn’t need to be refrigerated and can sit on the shelf for
up to six months.
Regular milk can undergo UHT, too. The process is used for the
room-temperature Parmalat milk found outside the refrigerator case and for most milk sold
in Europe.
So why isn’t all milk produced using UHT?
One reason is that UHT-treated milk tastes different. UHT sweetens the
flavor of milk by burning some of its sugars (caramelization). A lot of Americans
find this offensive—just as they are leery of buying nonrefrigerated milk.
Europeans, however, don’t seem to mind.
UHT also destroys some of the milk’s vitamin content—not a significant
amount—and affects some proteins, making it _unusable for cheese_
(http://www.sciam.com/article.cfm?id=dairy-farming-old-and-new) .
There are, of course, lots of reasons people buy organic milk. But if it's
the long shelf life you're after, I would recommend you buy nonorganic UHT
milk and avoid being charged double.
**************Vote for your city's best dining and nightlife. City's Best
2008. (http://citysbest.aol.com?ncid=aolacg00050000000102)
¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤
To unsubscribe/subscribe or view archives of postings, go to the Gambia-L Web interface
at: http://listserv.icors.org/archives/gambia-l.html
To Search in the Gambia-L archives, go to: http://listserv.icors.org/SCRIPTS/WA-ICORS.EXE?S1=gambia-l
To contact the List Management, please send an e-mail to:
[log in to unmask]
¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤¤
|