Have you ever noticed the cat's behavior when it is in the litter box? The cat may circle, like a dog, scratch at the litter, dig and then settle down to do its business. After the cat finishes, it scratches and digs some more, covers the droppings, and then leaves the box. The cat's paws are full of litter dust and waste matter, so it sits and licks them clean. Or at least as clean as a cat can get it. The cat's paws are still full of the bacteria from the box. And every surface that those paws touch are also receiving this rapidly growing and spreading bacteria. So if the cat jumps and lays around on the kitchen counter it is getting a good dose of bacteria. When you prepare your family's meal or the cat's food you could be giving everyone a large unhealthy dose of bacteria.
If you want to be healthy, you need to keep that cat off the counter. Letting the cat lay on the counter is providing an opportunity to dine on the contents of the litter box. Cat's love to look down from heights, you can accommodate them by providing another place to perch. Purchase or build a multilevel scratching post so that your pet can climb and lay around. You have to use an appropriate way to train the cat to stay of the counters and tables. Don't train your cat by spraying it with water or shouting at it. Some cats may resist you aggressively, and you will have a tug of war with it. Others may associate you with an unpleasant spray of water and loud noises. The cat could develop a neurosis and avoid you. Also, the cat could simply chose to continue jumping and lying on the counter when you are not around to bother it.
An alternative training method is to use something to make the "experience" less pleasant, but not traumatic. You could use a something sticky or noisy upon the counter or table top. If the cat jumps on the counter and its paws stick or it hears an unpleasant noise like the crinkle of aluminum foil, it probably will not jump on it again. Sticky tape or a strip of aluminum foil stuck to the counter will make the cat jump down. The cat will associate the noise and the stickiness with the counter. Or you could also use something that does not smell good to the cat. Cats don't like citrus smells. A lemon dishwashing detergent or a commercial cat herbal spray, may keep the cat away.
You should also keep the counters and table tops free of temptation. Don't keep food on the counter and the table. The cat may be jumping on the counter to help himself to a quick meal that could make him sick. It is best that cats stay off the counter. The counter and the kitchen table or not good cat perches.
