Rodents
Rats are able to squeeze through a ½ inch gap (e.g. gap under the door). Being prolific breeders, a pair of rats can produce up to 2,000 offspring in just one year. They pose a severe threat to food establishments by contaminating food, causing structural damage, and spreading diseases.
Cockroaches
Cockroaches can survive for weeks without food and even longer without water. They can transmit food-borne pathogens (e.g. Salmonella spp, Staphylococcus aureus) which are found in their guts and exterior surfaces, making them notorious carriers of diseases.
Flies
A single house has been estimated to carry more than 3 million bacteria. Flies transmit diseases through contact with faecal matter and decaying materials to food and food contact surfaces, proving to be a health hazard.