Before refrigerators existed, people would preserve products that needed to be kept cold, such as milk, by putting frogs in them.

In the past, each community had its own method of preservation. The ancient Russian and Finnish communities found a magnificent and very clever solution to this milk preservation: Throwing brown frogs called ‘Rana temporaria’ into milk…

A scientific study conducted in 2013 proved that this method worked.

 It was revealed that proteins such as Brevinin 1Tb synthesized from the skins of frogs (and other amphibians) restricted the life of some bacteria. 

Thus, the Russians and Finns discovered, albeit through trial and error, that they could fight bacteria by adding proteins produced from the skins of frogs to their milk.