University of Michigan paleontologist Daniel Fisher had a theory that early Americans of 10,000 years ago used frozen lakes as refrigerators to store mastodon and mammoth meat.
He tested his theory when a friend's horse died of old age. Fisher dropped chunks of horse meat of up to 170 pounds below the ice in a nearby pond. He anchored some pieces to the bottom. Every week or so he cooked and chewed a piece of meat, and eventually swallowed each bite. The meat remained safe to eat well into the summer.
The theory is that as the water warmed in the spring, lactobacilli (the bacteria found in yogurt & cheese) colonized the meat, rendering it inhospitable to other pathogens. So despite the smell and taste (similar to Limburger cheese), the meat remained safe to eat.
Scientific American, April 2000