Hi, This cheese has gone bad. The lunch meet has spoiled. The milk has soured. (Only used for milk or dairy products) The water in this pond is rancid. A very polite way to discuss this unpleasant topic would be to say a food item has expired. I am sorry to mention this but I think the applesauce has expired.

Along with Joe's and Kristy's great comments, we also say: The XXX is spoiled. For example, 'The lettuce is spoiled. We need to throw it out/throw it in the garbage/put it in the trash.'

I didn't expect such a lot of answers! Thank you to everyone! I got lots of new phrases!

The most common way I've put this and have heard others say this: "This has gone bad." Other ways, but in my opinion not as common: "This has spoiled." "It's rotten." "This is off." (slang) Or you can be specific as to what the problem is: "This is moldy." "This has curdled." "It has freezer-burn."

Based on the answers so far, it seems to depend on whether you are looking for UK or U.S. English. I'd say the food "went bad."