1. The common causes of chemical food poisoning in catering services are that the food is not cleaned: pesticide residues in unwashed vegetables and fruits.

2. Common causes of chemical food poisoning in catering services are incorrect use of containers contaminated with chemical poisons. For example, the containers used for eating have been contaminated with chemical poisons, which will contaminate them, and the poisons can enter the body with eating, thus causing chemical food poisoning.