Director-general Pornthep Siriwanarangsun said once the chicken and rice was cooked it should not be kept for more than four hours, because it could become contaminated by bacterial growth and anyone who eats it could fall sick.
Common symptoms range from stomach ache to diarrhea, severe vomiting, cramps, shivering, convulsions, exhaustion and unconsciousness.
He suggested chicken and rice sellers boil the whole chicken until it is thoroughly cooked. Cooked chicken that has not been sold should be scalded in boiling water for 15 seconds every two hours.
Dr Pornthep also recommended that shops that use frozen chicken should defrost it in a refrigerator one day before cooking it, not leave it to defrost in the open air.
They should not cook still-frozen chicken meat.
Rice served with the chicken should be kept at around 60 degrees Celsius all the time to kill any bacteria.
Side vegetables such as cucumber and coriander should be washed with water and then soaked in brine or vinegar for 15-30 minutes before cleaning twice more with water.
He also advised people to be careful in making up a lunch box with food that has coconut milk as an ingredient, or food that is not fully cooked, to reduce the risk of food poisoning.