Formalin is a chemical in the form of formaldehyde. People used formalin to kill germs and fungi. Medical used of formalin in the embalming prevent rotting. Properties that help kill germs and fungi caused people take formalin into the fresh food to remain fresh for longer. Nowadays, the problem of formalin in food is the Narong Sahametapat, permanent secretary for public health (2014) said that the Ministry of public health has a policy to control food safety. The food and Drug Administration choose at random food in the 5 market in Nakhon Sawan.