Ultrapasteurized half and half

March 24, 2006 3:26 PM

Does ultrapasturized half and half last longer than regular half and half once the carton is opened, or only in the unopened carton?
posted by Jackson to Food & Drink (11 answers total)

Pasteurization kills bacteria before the container is sealed, but doesn't do a whole lot to prevent later growth. Aside from the relatively small "head start" that the unpasteurized half and half has on the road to spoilage, there isn't much difference once the carton is opened.
posted by jenovus at 3:31 PM on March 24, 2006

I think that Jackson doesn't understand the point of pasteurization. It isn't to increase the life of the product, although it does to a small extent. It's to eliminate the kind of bacteria and fungi which are found at farms and on the skins of cows, so that you don't ingest them when you consume the milk/cream. (Things like salmonella.)

It will eventually become reinfected, and will go bad, but what it gets infected with is the kind of bacteria and fungi which hang around plastic cartons and your refrigerator. Not the same, and not as health-challenging.

It's not so much a question of when it goes bad, as what it's infected with before it goes bad. The only milk product which doesn't go bad is canned milk, which is genuinely sterile until the can is opened.

I have the feeling that "ultrapasteurization" is a gimmick term made up by a marketing droid. Pasteurization is pretty much all or nothing; either it kills everything or it doesn't, and if it doesn't I think it violates federal regulations. If it does, then more heat for longer doesn't kill any more because there's nothing left to kill.

But if it convinces you to select their product, and maybe to pay a higher price, then that's good enough for the marketing droid.
posted by Steven C. Den Beste at 3:37 PM on March 24, 2006

"I think that Jackson doesn't understand the point of pasteurization. It isn't to increase the life of the product, although it does to a small extent…
I have the feeling that "ultrapasteurization" is a gimmick term made up by a marketing droid."

According to Wikipedia:

HTST pasteurized milk typically has a refrigerated shelf life of two to three weeks, whereas ultra pasteurized milk can last much longer when refrigerated, sometimes two to three months. When UHT pasteurization is combined with sterile handling and container technology, it can even be stored unrefrigerated for long periods of time.

And I know that UHT milk in my grocery store has a much longer shelf life, according to the "sell by" date.
posted by mbrubeck at 3:45 PM on March 24, 2006

Yeah, from my experiences in Europe, I had (European) roommates who wouldn't refrigerate their UHT orange juice after opening it, and I observed them for several months without any of them dying.
posted by onalark at 3:57 PM on March 24, 2006

Maybe I'm too cynical.
posted by Steven C. Den Beste at 4:57 PM on March 24, 2006

um pasteurization most certainly does NOT kill everything. This was a question on several micro-biology exams. It reduces the bad guys, not sterilizes.
posted by yodelingisfun at 4:59 PM on March 24, 2006

From my purely unscientific anecdotal experience, ultrapasteurized dairy products last much longer than normal pasteurized dairy products, even after being opened. I keep a carton of milk in the fridge at work. I don't go through it quickly though, and used to have to throw out the bottom third or so. Ever since I've been buying the ultrapasteurized stuff (several months now), I don't have to do that. The stuff lasts what seems like forever. Weeks. Even after opening. (Of course, it's possible that there are odorless bacteria in the very old ultrapasteurized milk. I don't know. I haven't tested it. It tastes and smells fine, though.)
posted by jdroth at 5:03 PM on March 24, 2006

Best answer: Just going on experience, I can let an opened carton of ultrapasteurized cream sit in my fridge for ages without it going bad. Definitely longer than milk. Keep coming back to it thinking, "Well, surely it's gone over by now," and - nope. It's a phenomenon I had noticed before I'd ever noticed the word "ultrapasteurized."
posted by Wolfdog at 5:07 PM on March 24, 2006

Ultrapasturized dairy products generally do NOT require refridgeration. If you check the creamers at a restaurant that leaves them out all the time, you should see the word somewhere on the containers or on the shipping container.
posted by fvox13 at 5:47 PM on March 24, 2006

hmm.
On preview, ultrapasteurization would seem to yield more local colonization rather than less, if it is simply more of the same. Kind of like Clostridium dificile colitis being linked to antibiotic use--kill the kind bacteria, and other bacteria have more resources to grow.

Maybe it has something to do with having the milk not curdle, versus not have it grow some science project. I'll have to look into that. BRB.
posted by gilgul at 7:55 PM on March 24, 2006

a lot of ultrapaturized products are put in milk cartons that are skived not sealed ... meaning that the inner panel is folded over again so that only smooth board and not the edge is exposed to the product ... the result is a package that will keep the product fresh longer

i have no idea whether it keep better once you open it up ... but i know for a fact that doing this will add weeks of shelf life to the product

(i'm the guy who tests the milk cartons to make sure they won't leak ... skived or sealed)
posted by pyramid termite at 9:18 PM on March 24, 2006