Are guinea pigs allowed to eat frozen corn?

They can, but won't necessarily digest it well. Cats are obligate carnivores. Though, we had one domestic shorthair that enjoyed snacking on corn-on-the-cob, as well as pistachiOS, raspberries, sugar snap peas, peaches, bananas, winter squash, grass and catnip. We think he might have been a dumpster-diver before we got him.