The reasons for this situation are food safety, nutrition and environmental protection.

1. Food safety problems: There will be problems such as substandard hygiene and excessive additives in the production process of prefabricated vegetables, which will lead to the decline of food quality and pose a threat to consumers' health.

2. Nutritional problems: The prepared vegetables are often stored and processed for a long time, and the nutritional components are seriously lost, which cannot meet the nutritional needs of the human body.

3. Environmental protection: A large amount of garbage and waste will be produced during the production and use of prefabricated vegetables, which will pollute the environment.