It becomes watery and sometime fungus grows, and it has a bad smell. It loses its firmness.

Tofu doesn't cost that much, so get rid of it.

From September... nope.

6 months is a long time for something wet to grow stuff

Tofu lasts a long time, so I would probably sniff it, maybe poke it, and eat it. But if you are not sure of your ability to judge the smell, you should definitely toss it.

Unopened in the original packaging, you open it and look for spots or discoloration anywhere on the surface of the tofu. If there isn't anything, you sniff. If there's no odor, you can eat it.

I've eaten tofu expired for months, and I've had to throw out tofu before the expiration date because it smelled bad and had obvious bacterial colonies growing on it.

I’m VERY lax on this kind of stuff and I wouldn’t eat it, although I think you’d be able to smell if it was bad. Tofu is dirt cheap, just toss it.

How about you don't eat it

Food poisoning is so common for young adults. Especially in their 20's. Because of poor decisions

I've eaten tofu that old and it's fine as long as well sealed. I also have opened tofu that went bad and the smell was really strong.

I’ve eaten old tofu as long as it’s in the original package and not noticed any difference . If it’s been opened and sitting in water I’d toss it.

I forgot about package of tofu in water, sitting in the back of my fridge. With most stuff I will just eyeball it but I really can't tell with tofu since it already has a strong smell to me normally. Is there a way to tell?

The best-by date was Sept 2021 ...