In order for pests to feel comfortable and survive well in a food facility they need access to

Food, water and shelter

Pests invade human places in order to obtain the resources they require for survival, namely food, water and shelter. Therefore, if pests obtain access to these resources, they are likely to stay and reproduces, resulting in an increase in pest population in the area. Therefore, the best measure for preventing pest infestation is to prevent access to such resources.

It's called the nephron.