NOTICE TO ALL: Really, I am not recommending this following!!!
I just read an article about a VERY interesting way that was used, once upon a time, to keep milk fresh. It involved a pretty common amphibian taking a bath in some milk. Have I piqued your interest?
So what was this method? Drop a live frog in your milk. Seems like long ago, in some areas in northern Europe, a live frog would be put in the raw milk to keep milk fresher. What is interesting to me is that there is some evidence that this might actually work. Turns out that frogs' slime produces various antibiotics on their skin. When the slime was mixed with the milk (the frog takes a milk bath) those slime-ular antibiotics kept milk spoilage down, giving more shelf-life to the milk.
Now I just want to let you all know that I am NOT recommending making frog milk-baths, but it IS interesting. I mean, if you don't have a fridge, and the weather is warmer and you have a bunch of milk you need to hold a while longer. . . People are pretty observant and creative. Humans figured out how to cheese with bacteria. Kimchee and sauerkraut are products of fermentation also. Using frog slime to preserve milk is another example of humans putting bacteria to work.
Here is a link to the article I read: Refrigerators that Ribbit at NowIKnow.com .
And here's the link to more in depth information (given in the above article) about frogs in milk: "If Your Fridge Dies, Should You Put Frogs In Your Milk?" at Treehugger.com.
And knowing that just about anything is out there on the net, well, I would not be surprised if someone has detailed instructions about how to best use a live frog in your milk to keep it fresh. And I beg to decline to supply a link for instructions on how to do so! :-)
And again, I am NOT recommending this. You have a fridge--use it!