the extra bacteria for vege fermentation come from their spit which is infested by their rotten teeth from utter lack of dental hygiene. every time they open their mouths and talk in the kitchen, a billion nasty bacteria fall on the food they're preparing. that's even nastier than the rotten vege they pick up from the ground. :*:
but they add a special knock-your-socks-off flavor to the meal. :p