Why does a carton of heavy cream last for 2 months in the refrigerator, but a carton of milk only lasts for about 1 week before expiration?
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Heavy cream is usually UHT or Ultra High Temperature pasteurized – basically they heat it up to well above the temperature that greeblies can live at for just a few seconds – enough to kill the greeblies but not long enough to cook or chemically alter the cream (too much).
So raises the question – how come all milk isn’t UHT pasteurized? It does carmelize some of the sugars, so it will sweeten the flavour a tad. It isn’t noticeable in your heavy cream because of all the fat and sugars already, but would be noticeable in milk. Plus, it requires special sterilization and sealable containers to be effective, plus you’re opening that milk constantly several times / day so there’s no point if you’re reintroducing airborne greeblies. Not true for the cream (unless you’re, for some reason having whipped cream with every meal?)
Creams are ultra-pasteurized, or UHT processed. Just means higher temp (ultra high temp) plus the additional fats help out too. Lower temp or standard pasteurization on milk and lower fats make all the difference.
There are two big reasons here:
1. Bacteria love environments with lots of water, and cream has much less water content than milk. Because it’s got a higher proportion of fat, bacteria can’t get the water that they need as easily, and they won’t grow as quickly. Cheese is the classic example when it comes to dairy – we take out most of the water, add salt, and preserve our milk for months. Cream has more water content, but still isn’t an ideal environment for bacteria, while regular milk is full of water and lactose for them to live on.
2. In the US at least, most milk is regularly pasteurized, but most half-and-half and heavy cream is ultra-high temperature (UHT) pasteurized, which makes it last significantly longer. A lot of other countries sell mostly UHT milk, and you can buy it in the US as well (a lot of organic brands do it) – it’s got a slightly different taste, but it lasts for months. Cream, since they don’t sell as fast as regular milk, is usually UHT pasteurized to make it more shelf stable
Depends son if the heavy cream has stabilizer in it or not. With out any stabilizer the cream would end up lasting a week past it’s code date, so right around 30days before notable flavor and odor change. Most milk you get from the store will usually last only 2 weeks because it has been sitting in storage for a while, because stock rotation, you get rid of old before new. Someone else here mentions UHT or ultra pasteurization which can be useful, for non-dairy based milk, because of the caramelization of the milk sugar, to put it simply. Most dairy’s here in the states utilize a HTST system, which is high heat short time,which stabilize thebmilk to last around 20 days or up to 27 days. Cream follows the same rules as milk. The biggest cause of milk going bad earlier is because of a few factors, stabilizer in the cream to help it last longer, a piece of equipment was not cleaned as well as it should have been, or most common the raw milk before pasteurization had a high P.I count/tested positive for ropy, which makes the protein in the milk bond in a pretty cool way and it pours out like string. Really cool to see, will make you VERY, VERY sick if you consume it.
Source: I’m a dairy lab technician.
One thing I don’t see mentioned is the tradeoff in whippability (hey, new word!) of UHT cream. You’ll note that UHT pasteurized heavy cream has carrageenan, gums, and stabilizers to restore the texture and ability to whip successfully. I only purchase heavy cream when it’s needed for a recipe, and I find the tradeoff of longevity vs. usability unacceptable. On the other hand UHT pasteurized milk is a fabulous thing, because I don’t use milk all that much and the UHT product means I waste a lot less milk.
Just a head’s up, but costco sells 4 half gallons (in a 4 pack boxed in cardboard)of all natural organic milk and it lasts like 3 months in the fridge with no difference in taste, my wife and I love it. Tastes way better than the plastic bottled stuff.
Live-culture buttermilk lasts forever in the fridge. I’ve had half-gallon jugs last for months and months. Why exactly is this? Is live-culture yogurt like this?
Holy shit I was literally wondering the same thing this morning as my mom brought out milk and cream for my dad and I during breakfast, I remarked how the half & half cream we currently have expires in August while our milk expires next week…
I am a bit confused, please clarify: my fresh milk usually has a best before date 2-4 weeks in the future; one week sounds really short. In my experience, it often is perfectly fine a week or two after, too, as long as it has not been opened yet. Meanwhile, UHT milk has dates two or maybe three months into the future…
I thought I read somewhere, sometime (sorry so vague but I’m old) that light affects time to spoil. Milk in cartons lasts longer than milk in plastic jugs because the carton blocks the light. Is this true?
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