Cats are opportunistic meat-dependent eating machines equipped with a dedicated on-board protein detector colloquially referred to as a "nose" -- hence their interest in tuna and prawns.

Our cats will sample whatever high-protein foods they can get within tongue's reach of, but they rarely do more than taste -- reared in the safety of our kitchen with a constant supply of kibble, they are merely maintaining their situation awareness with respect to the local food supply.

People who cook in the constant presence of cats develop little routines to reduce the risk of contamination, or -- more simply -- to mitigate the ick factor. For example, I am a tad obsessive about not allowing food to touch the surface of the kitchen table unless its next destination is the cooker. Likewise, all cutting boards have a "clean" topside and a "dirty" underside, never to be confused. Despite the wanderings of two completely undisciplined cats, neither of us has ever suffered so much as a twinge of gastro-enteritis.