Learn Italian: Questo formaggio fa schifo! - This cheese is disgusting!

You can add the pejorative suffix to formaggio to make formaggiaccio, which means "bad, nasty cheese". You could simply exclaim Che formaggiaccio! (What a terrible cheese!) to express a very similar idea without needing a verb.

Why does the sentence use fa (makes/does) instead of è (is)?

In Italian, the idiomatic expression for "to be disgusting" or "to suck" is fare schifo. It literally translates to "to make disgust" or "to cause disgust". You will often see the verb fare used where English uses "to be", such as in fa freddo (it is cold).

If I change the sentence to "These cheeses are disgusting," does schifo become plural?

No, schifo stays exactly the same! Because schifo is a noun meaning "disgust" and not an adjective, it doesn't change to match the subject. You only need to change the verb to plural: Questi formaggi fanno schifo.

Can I use fare schifo for things other than food?

Yes, it is an extremely common phrase used for anything that is terrible, of poor quality, or figuratively disgusting. For example, you can say a movie fa schifo (the movie sucks) or the weather fa schifo (the weather is awful).