I know that the particle же is used to remind someone of something they should already know. For instance, say my friend and I posted a nasty comment on someone’s Facebook, but then quickly deleted it. Then that person seemed angry with me a few days later and my friend suggests that it’s because of that comment. I could say to him: Она же комментарий так и не видела, to remind him that we deleted it before she could see it, which in English would be But she never SAW that comment. In English the stress on the verb saw has more or less the force as же in the same Russian statement, I believe.
Getting to the point of my question, I saw a sentence recently: Суп-то у нас того... испортился. Staying within the theme of the spoiled soup, let’s say my wife suggested that we serve our guests soup; I could potentially say Суп же у нас испортился, which would mean: But the soup (as you know) was RUINED. Again stress on the verb in English.
My question is: How does the use of -то in the sentence Суп-то у нас испортился change the semantics of the same situation as expressed with же. Does it, like же, also imply that the listener already knows about the soup being spoiled, or does it shift the sentential stress and focus onto the soup and make the whole statement a piece of news about the soup and what happened to it? In other words, what other underlying nuance(s) does it express that makes it different from же?