It's part of an emerging industry that's trying to cash in on a senseless human problem: The huge amount of uneaten food that goes from supermarkets and restaurants to the dumpster. Much of that, if it's not composted, ends up in landfills where it decays, sending potent planet-warming greenhouse gases into the atmosphere. Enter a new business opportunity. A company called Winnow has developed the AI tool that spies on restaurant garbage. Another, company, Afresh, digests supermarket data to look for wasteful mismatches between what a store is stocking, and what people are buying.