Those who read Michener's "Centennial" might remember this person in there who carried a sourdough starter on his body on his trek to the Klondike and started some form of business based on it there. I read it just out of primary school (about 40 years ago) so I don't quite remember the details but the practice of keeping the starter for some fermentation process alive over a longer period of time is known and practised all over the world.