In food businesses chemical agents must be avoided as far as possible. There is a risk of contaminating the food and the dead rats stink horribly. However, it is advantageous to place boxes of rat poison in strategic locations outside buildings, so rats are fought before they find their way into buildings and establish themselves there. When rats are inside buildings one should use the snap traps, so the dead animals can be easily removed. Use plenty traps. Place them with the trigger mechanism against the walls and make sure the bait is well fastened. In special cases, one must resort to extermination with poison.
The local authorities can provide a list of pesticides that may be used for rodent control.