Cats that are kept indoors do not have access to grass. Pet shops sell grass seeds, which you can plant inside your house and let your cat eat. There aren't any pet shops in the vicinity of my home. You can use mail-order shopping. Check the useful links page.
Cats swallow their food without chewing, so extreme temperatures of food are dangerous.
Spicy food is too strong for cats. Hard to digest. My cat behaves very strangely if it eats silvervine. There's no need to worry about it. If your cat eats this frequently, it will not have a strange reaction.