Why do higher fat milk products last longer?

Question

Why is it that when I look at the expiration dates on milk products, as the % of milk fat goes up so does the self life? Skim milk may be a couple of weeks while heavy cream may be a couple of months. Why is this?

I mean shelf life, sorry.

Answer 1

Bacteria don't reproduce as quickly in a high fat environment, because there is less air. That's why you can leave oil and shortening and lard and butter (to an extent) sitting at room temperature and it doesn't spoil. It does develop a "stale" taste after a while, though.

Answer 2

I don't know about that. Cream has always lasted longer than regular milk in my fridge, but I have half a gallon of 2% that should have expired at the end of March, but it still good. Whole milk won't keep that long for me. I'm not sure it has to do with the fat content.

Answer 3

The heavy cream will go bad just as fast as the skim milk once it is open. All milk products will last about seven days after you open them. The creams are ultra-pasteurized and that gives them a longer shelf life before they are opened.

Answer 4

I would think the opposite would be true, as fat can turn rancid.
I can't find anything that says the fat content of dairy products affects their shelf life. They may be processed differently. The person who mentioned "ultra-pasteurized" is probably on the right track.

http://pubs.acs.org/cen/whatstuff/stuff/7945sci2.html

Read this article too

http://www.fst.vt.edu/extension/drg/dfax/1105.html

Answer 5

its true as i have been buying blue top now as before did semi skimmed , but when its only me i find it was going off too quick , full fat can last weeks if kept cold enough , and put away as soon as you have finished with it , im sorry but i dont know why , but glad you asked the question as i may now find out , thankyou x

Answer 6

i've found it to be just the opposite... lower fat content, higher shelf life.