They are a great way to recycle food scraps and other organic materials. Not only are they are easy to care for, they create high quality, valuable compost using refuse like food scraps from schools, cafeterias, prisons, and manures from confined animal operations.
Worms eat decomposing organic matter and the small organisms that are involved in decomposition.
You can feed them kitchen scraps but to avoid odors don't feed them meats, oils, beans, etc., the same things that you would also avoid in a compost pile. I also avoid strong foods like garlic, or fruit, because of the fruit fly problem. Manage a worm bin as you would a compost pile. In prime conditions worms can eat their weight or more each day. Start slow and feed only what they can eat in a few days, to avoid heat from decaying matter.