The vast majority of milk we drink is pasteurized - heat-treated to kill off harmful pathogens. Raw milk, on the other hand, goes straight from udder to bottle. Fans call it milk as nature intended: nutrient-rich and full of probiotics, the good kind of bacteria. Some fans go further, calling it a superfood that aids digestion, boosts the immune system and treats asthma, eczema and allergies. Due to concerns about safety, retail sales of raw milk are prohibited in about 20 states. Something called a "herd-share" scheme ... lets people buy an "interest" in a group of dairy cows. "As a part-owner, you're entitled to what that cow produces," [food blogger Jennifer McGruther] explains. "It's difficult for the state to say you can't drink the milk from cows you own." The US government estimates that 3.2% of people now drink it. But ... pasteurization is the norm for a reason - it's highly effective at killing things such as E coli, salmonella, campylobacter and listeria. Raw milk, on the other hand, relies heavily on the skill of the farmer and the cleanliness of the operation to avoid contamination. A study published by the Centers for Disease Control and Prevention (CDC) says raw milk illnesses have spiked as more people drink it. Between 2009 and 2014, raw milk and raw milk cheese caused the vast majority (96%) of all illnesses linked to contaminated dairy products. Several European studies and observations of Amish farm children do suggest those who drink raw milk have less asthma and fewer allergies.