How does fat cause milk to curdle?

I think you will find that the opposite is true. Full fat yogurt and cottage cheese as well as 4% milk (I never buy the lower fat kind) actually last longer than the skim, lowfat and 2% kind.

Consider that French peasants traditionally used goose fat as a preservative, although, I think in that situation the goose fat preserved by keeping oxygen out.

Consider what causes curdling: acid.

yeah, both 1/2 &1/2 and heavy cream always last longer in our fridge.

http://www.ehow.com/how-does_4572637_what-makes-milk-spoil.html


http://wiki.answers.com/Q/Why_does_milk_curdle_when_it_goes_bad

so after reading the above I am left with the question of milk fat content re curdling.

Butterflynet's answers seem to indicate that fat has little to do with the process.

http://wiki.answers.com/Q/What_causes_milk_to_curdle


What I read there is : "high temperatures, acids, tannins, enzymes, and salts"

I'm not professing knowledge on chemistry therein, but what could be implied could be a relationship with the enzymatic activity and the presence of milk fats.

Reading this 3-page article on milk curdling will give him the answer he seeks regarding fat content and curdling. The details regarding percentage of fat and curdling are on the last page.

http://chestofbooks.com/food/science/Experimental-Cookery/Coagulation-Of-Milk.html

ok I realize I don't read well and am easily confused butI can't find the part that explains fat content of milk and curdling.

factoids;
In the olden day (when this poster was a mere prat of a child) the price the dairy farmer got for his milk was determined by fat content, more fat = higher price, this resulted in such cows as the Brown Swiss etc to be prized because, with high quality feed, they produced high fat milk. When the pricing rules changed to simply price the milk by the poundage dairy farmers started switching to cows such as Holsteins which, even with lower quality feed produced many more pounds of lower quality milk.
Another factoid, for thos of us that have relied on milking our own cows for milk/cream/butter, the term used for curdled milk was "blinky" as in "this milk has turned blinky."

I am doing the same experiment and mine is due really soon. I also got the same results as you and I was wondering what you did in your presentation because I don't think I have time to redo the project, not that my results will change... Please answer as soon as you can!
Thanks!

Try channeling Louis Pasteur.