Altruists and envious people who meet in contests are symbionts. They do better than a population of narrowly rational individuals. If there are only altruists and envious individuals, a particular mixture of altruists and envious individuals is evolutionarily stable.

The frequent exposures of food safety events in recent years have aroused extensive social concerns. Food quality and safety are hot topics in the food engineering field. In a market with mutual competitions, the products of different enterprises are substitutive, and enterprises have to achieve...