http://www.straightdope.com/columns/read/929/why-is-there-an-expiration-date-on-sour-cream
I think the much more important question on the subject of sour cream is how can they sell “Fat free sour cream”? Which seems a bit like selling water free water.
Yeah, it should really be called “sour cream flavored product” or something. Fat free sour cream has a lot of added sugars and thickeners. Real sour cream is only 30 calories per tablespoon, anyway.
I guess you’re focusing on the “fat free… cream” part?
Yeah, that seems counterintutive. But if you can get a semi-congealed lactobacillus fermented milk product, it’s called “sour cream” even if it’s not cream based. (Unless it’s called “yogurt”. I’m a little unclear on the distinction, TBH.)
It’s all marketing, anyway. And I’m sure that the marketers would argue that once you arrive at a certain tartness and consistency, you can call it “sour cream” regardless of what you started with. It’s a lie, but what marketing isn’t?
That is a bit like Samsung marketing a iOS free iPhone.
Is it a fact that “some sour-inducing microorganisms invariably survive pasteurization,” as Cecil says? I’d think it would be easier for sour-inducing microorganisms to be introduced after opening the container than for them to survive pasteurization.
Dunno about “sour-inducing”, but some microorganisms inevitably survive “pasteuarization”
Partly because microorganisms are like cockroaches or rats, mostly because pasteuarization aint pasteuarization.
When Louis Pasteur invented pasteurization, he invented Long Life Milk using Ultra High Temperature processing. This gives milk a distinctive scalded flavour.
A common claim (dunno if it is true or not) is that what he was trying to do was to make milk safe to drink. This only requires temperatures high enough to kill common dangerous pathogens, and gives milk only a subtle scalded flavour. This is what happens to normal pasteurized dairy products.
Unless you are careful, pasteuarizing milk to make it safe to drink actually makes it more likely to go off, because warming milk encourages the growth of sour-inducing microorganisms. I guess milk suppliers are careful, but I have inadvertantly bought flavoured milk past it’s use-by date that has gone off, even though unopened.
Ah, good points, Melbourne.
Now how about evaporated milk – what keeps that from spoiling? Hotter pasteurization? Or is it that being canned provides a more effective barrier against microbes? I know the lower moisture content is part of it, but bacteria can still grow in it, if left opened: http://www.milkingredients.ca/index-eng.php?id=179
I’d suspect one difference is that the milk can be pasteurized within a sealed can, but not within a plastic bottle or paper carton; there’s probably room for the introduction of microorganisms between the time of pasteurization and bottling (including maybe using a not-so-sterile bottle).
Which prompts the question: half what? And what is the other half?
Weird – cream is an ingredient in the “fat free” half & half.
This sounds a lot like the “0 calorie” packets of artificial sweetener, which are composed mainly of dextrose (a.k.a. glucose) and maltodextrin (i.e., they definitely have calories). They size the packets just right so that they can take advantage of an FDA loophole that allows anything containing fewer than 5 calories to round down to 0 calories on its labeling.
Since the serving size of the half & half is only 2 tablespoons, I’m guessing it would be easy to round down the fat out of [ostensible] existence. Mainly, though, they’re apparently just replacing the cream with corn syrup, as if that’s so much healthier for you…