I wonder why dairy milk goes sour on the day of expiration but soy milk can still be good a couple of months ?

Question

after expiration? and dairy milk if it sat out of refrig all day would spoil, but soy milk I left out of refrig (by mistake) all day and put back in refrig and it was still good? Why?? More germs in dairy milk? Or maybe lactic acid is the culprit?

No, I am talking about Silk (quart size) that was opened and left out accidently all day (12 hours) and it was put back in refrig and it was fine to drink (but will not do that on purpose)...

I am a vegetarian (or working on it), and Silk is most economical and easier to buy than to waste gas driving 20 miles...might try making my own...I am working on that too...time is an issue also with making my own soy milk...I have had sealed silk last about 2 months past expiration in refrig.

Answer 1

You got it right in your next to the last sub-question. Pasteurized milk still contains germs and spores that are able to survive the brief burst of heat we call Pasteurization! Soy milk is *cooked* to produce the 'raw' soymilk and in the commercial products like Silk it gets a final heat blast just before packaging. There's just not that many organisms that can survive that kind of treatment!.

What's really wacky is that USDA reg's are *much* stricter for bacterial contamination of soymilk! Soy milk for human consumption has to test at less than 1,000,000 cells per liter. Cows milk is allowed to have up to 750,000,000 per liter!
YUCK!!!!

Answer 2

If you open soy milk, and leave it in the fridge, it can and will spoil within the same amount of time as regular milk.
Soy milk is pasteurized.
There is no special law for the pureness of milk.

I keep both kinds of milk in my fridge and they both go bad about a week after the ex. date.
Maybe you are referring to the UHT, pasturized, cartons of soy milk that are sold on the shelf, un-refridgerated. Those last for a few months, if unopened. And cow milk is avaiable some places the same way.

Answer 3

Just so you know, if you don't drink cows milk for ethical reasons, it's pointless to buy Silk soy products instead because they are owned by dairy companies. Try a lesser known and local soy product company so you aren't contributing to the dairy industry.

Answer 4

Its due to the lack of animal protein in soy milk. Animal protein forms amines which cause dairy milk to break down faster. Soy milk, being derived from a plant source does not form amines and enzymes that will break it down, causing it to sour. Lactase and lactose, the sugars found in dairy milk, are enzymes that contribute to the deterioration of dairy milk. There is most certainly more bacteria and germs in anything derived from an animal

Answer 5

Dairy milk doesn't go sour on the day of expiriation. I've had milk stay perfectly sweet several days after the date on the bottle. As long as your refrigerator is cold enough and your nose is working properly you should have no issues determining whether things have gone off or not. Save with soy milk.

Soy milk is full of all kinds of ingredients and preservatives which will aid in longer shelf life. Dairy milk, by law, has to be pure and eventually the freshness will fade.

Answer 6

my milk stays fine up to 2 weeks after the expiration date. as for leaving it out, it probably has to do with the fact that soy milk is not an animal protein.

Answer 7

Some milk guy told my mother that milk spoiling had something to do with how much it's pasturized. . so maybe soymilk isn't pasturized.