My cat keeps getting food, litter, and occasionally poop in her cone?

She got spayed 3 days ago and she has to wear it for another 11 days. Her food is constantly getting in her cone and her litter and poop are getting in there when she smells her litter box before using it. She keeps licking her cone and she might have ingested some of her poop and litter. How can I prevent this from happening when i'm out?