Cockroaches in a commercial kitchen can be a huge problem. To remove all residues of food debris in a busy kitchen is extremely hard so there will always be food availability making baiting hard.
However using cockroach bait is still the most effective method. It needs to be applied to where the main populations of cockroaches are.
Using residual insecticides can still be effective. In the photo the technician is applying the insecticide behind the metal cladding which is a common place for cockroaches to hide.
Pest Control Wirral and Chester