My nana is 95 and no matter what we do she will not throw out expired or bad food for example
"Nana this milk smells really sour im going to dump it out"
"now wait let me smell it........ Oh no no no its only a little sour I can drink it will its almost a solid"
and when we try to throw anything away she will actually go into the garbage and take it out
and to make it worse she complains of chronic nausea and stomach pain so much that she has been on 6 different medications for it
is there anything I can do
Sometimes we come across battles that aren't worth fighting. This is one that's worth fighting. Your grandma's going to make herself sick(er).
Better safe than sorry. I take it all home with me and put it down my disposal (she doesn't have one) or give it to my squirrels if it's just dried out bread or other things that are still technically OK, but not good enough for my mom to eat. So do something similar. Just sneak it out if you have to.
When I first came to live with my parents, some of the food had dates that were 20 years old. There was a sweet potato pie from 1990. I was about to toss it out and she protested. I asked her if she was going to eat it. She said no. I said I wasn't, either, and in the trash it went. Some things are important for us to be the boss. Some old people hoard food, which can be very unhealthy. If you know it's bad, then trash it.
As others had mentioned, don't say anything to her, just toss the expired food out. But be sure to replace it with updated products.