Generally it's not advised to fit carpet in kitchen. Tiled flooring or even laminate or wooden floors would suit kitchen much better than carpet. However there are durable and easy to clean carpets available on the market.
Probably the best option would be fitting carpet tiles instead of large one piece carpet. In case your old (or new) fridge gives up and you need a fridge freezer repairs after it left a wet patch on the floor. It's not just fridge, but any other domestic or kitchen appliance that might give up it's ghost.
If you still want to go for carpet in your kitchen then choose dark colours and carpets with pattern will work better as well. Depending on your current floor surface, you might not need to lay your carpet at the same time when kitchen is fitted.