Last May, Whole Foods recalled two types of curried chicken salad that had been sold in some of its stores in the Northeast. The retailer's kitchens had accidentally confused a batch of “chick'n” salad made with a plant protein substitute with one made from real chicken, and reversed the labels. “None of the customers apparently noticed the difference,” said Ethan Brown, founder and chief executive of Beyond Meat, which made the substitute in the product that was recalled. Demand for meat alternatives is growing, fueled by trends as varied as increased vegetarianism and concerns over the impact of industrial-scale animal husbandry on the environment. The trend has also attracted a host of unlikely investors, including Biz Stone and Evan Williams of Twitter, Bill Gates and, most recently, Li Ka-shing, the Hong Kong magnate. “I've tasted a few,” Mr. Gates wrote in a multimedia piece on the Beyond Meat investment that was posted to his blog, “and they're very convincing.” Mr. Brown said that one of the big agricultural commodities businesses that trades in meat also has a tiny stake in Beyond Meat, though he declined to name it. Some investors look at the development of viable meat alternatives as a sustainability issue.