Dont know if anyone else with animals has this problem, but I would certainly appreciate any tips you have........

Now that the weather is getting really warm flies are a nuisance! I have my cats feeding bowls near the back door of the kitchen & if my cat doesnt eat all of her food in one go (which she most often doesnt, she likes to pick) then flies come in when I have the door or window open & lay eggs in her food bowl! Yak!!!! Im forever chucking her food out & cleaning the bowl.
Is there any way of preventing this? (apart from the obvious of keeping the doors & windows shut lol)