The company Shiok Meats in Singapore aims to bring laboratory-grown shrimp to the food industry. Concerns about health, animals and the environment are leading more people to remove meat from their diet. Plant-based meat alternatives, popularized by Beyond Meat Inc. and Impossible Foods, increasingly appear in supermarkets and restaurants. But what some people call clean meat, meat grown from cells in a laboratory, is still an idea that is just beginning. More than 24 companies are testing lab-grown fish, beef and chicken. These businesses hope to enter the alternative meat market, which could be worth $140 billion by 2029.