What do I do about my boyfriend's mother?

She’s one of the nicest people I’ve ever met. Let me get that out of the way.

The problem is that she has no concept of when food spoils. She has no sense of smell from some old botched medical procedure and her mother was a “Depression kid” so she’s grown up with the “waste nothing at any cost” attitude. She has a habit of using spoiled food in her cooking and nobody realizes it until it’s too late. This morning, she made my boyfriend ham and eggs, and he realized when he was through that the ham was left from our camping trip over the July 4th weekend.

It’s very hard to decide how to deal with this because she’s always trying to make sure everyone is fed; she’ll get up and cook a meal no matter what time you get home from work and have it ready when you get home… that type of thing. But it’s too unhealthy and terribly unpleasant when you constantly have a stomach issue. How does one handle this?