Some people claim that we’re better off getting our probiotic bacteria from dirt than from foods like yogurt. But are these products safe? Scientific American presents Nutrition Divaby Quick & Dirty Tips. Scientific Americanand Quick & Dirty Tips are both Macmillan companies. Nutrition Diva listener Vicky asked me to do a show on soil-based organisms, beneficial bugs that some people believe to be even more helpful than the friendly bacteria that you’ll find in probiotic…