Longer than milk that has a higher fat content, that is…
Personal experience only, no cites:
When we buy 2% milk, we can usually keep it around for a week, maybe a week and a half, before it starts to smell “off”. Skim milk has lasted for up to three weeks for us. Soy milk lasts even longer than that.
Lactaid, milk that is easier to digest for people with lactose intolerence, has a much longer life. I don’t know exactly why, but I buy it for that reason only. Check the expiration dates on the cartons.
When I was in college, I recall the cafeteria manager telling me the opposite was true: that skim milk went bad more quickly than whole milk.
We need a cite.
Found a fifth grader who says whole milk spoils faster, and a seventh grader who says skim milk spoils faster.
Most of the sites from the dairy industry don’t seem eager to dwell on the idea that their product might spoil.
I think that unless you ran a highly controlled study where all the different types of milk were handled exactly the same way from cow to consumer refrigerator, you might be able to decide something.
However, this dairy company’s website
http://www.darigold.com/questions.asp?page=5
seems to indicate that dairy products have many opportunities to spoil.
I didn’t know you could freeze milk for 30 days. I think that milk would taste awful. My father tried that technique with egg nog, so he could drink it in July, but it was a dismal failure.
I suppose it depends on what, actually, spoils in the milk. If the milkfat was the source of goodies for the bad guys then it certainly seems that 2% would spoil faster.
In personal experience, skim milk did indeed last longer, but I find that I can explain that away by how much I don’t like skim milk, and it took me longer to notice. 
Slight hijack.
Has anyone else noticed that certain brands seem to last a very long time (by milk standards)? I’ve been purchasing Land O’Lakes lately and the date on the carton is between 4-6 weeks in the future.
[slight hijack] I understand that the calcium content (vol per vol) is higher in skimmed milk than whole milk. Better for the teeth & boney bits folks![/slight hijack]
I’d like to see a cite for this. I have three jugs in front of me; whole milk, reduced fat, and fat-free. If I recall, these should be 3.5%, 2%, and 1/2% in fat content. All of them list 30% calcium on the nutrition label.
I used to freeze 1% milk when I lived so far from a grocery store that I only went once in 2 or 3 weeks. I never noticed any off flavor to the thawed milk, but there was one problem: the plastic jugs tend to burst when the liquid expands in the freezer.
Spoke with a representative of Dairy Management Inc, apparently the collective marketing arm of the American Dairy Association, the National Dairy Council, and the US Dairy Export Council. She contacted an unnamed professor of food science at the University of Wisconsin. Here is the reply:
[quote]
Milk of different fat levels should spoil at approximately the same rate if the following criteria are met[ul][li]They are of equal freshness[]They receive the same pasteurization processing[]Total solids content is approximately the same (protein-fortified or not)[]They are stored under the same refrigeration[]They have the same time after processing (sell-by date)[/ul][/li][/quote]
dqa,
I can only say that your dedication in getting to the truth of this matter is nothing short of awesome.
I take my hat off to you sir.
However the Dairy Management Inc opinion doesn’t seem to tally with anecdotal (and indeed my own) experience which is that skimmed milk seems to last longer.