Short answer: handle food appropriately and keep clean areas.
EXPLANATION
A chemical hazard arises from having contact or exposure to chemicals that can produce negative health effects. Also, a person who works handling food must be very careful in his/her job to avoid putting himself/herself at risk and the people who are going to consume the food that he/she prepares. Therefore, a food worker has to keep chemicals away from the place where they handle food, clean the surfaces in which they handle food, and carefully wash food because these can have pesticides, and deposit chemicals away from food.
True, vaccines are small doses of the virus in which the body will fight off and learn from it. your body next time will know how to fight the disease, making you immune.
