MIL telling husband to lie

This morning my MIL came to watch my LO while we work. They were downstairs and my husband was telling her what to feed LO for lunch from the fridge. One of the things was beef stroganoff that I forgot to throw out and had been in the fridge for two weeks. I called down from upstairs and said “oh that’s been in there two weeks, it needs to be thrown out” and I heard her whisper to my husband “just say OK, she shouldn’t waste food like that.” Well he didn’t say anything so I went downstairs and started to toss it and told her I heard what she said and I don’t appreciate her telling my husband to lie to me. She literally smiled and said “well I would have eaten it.”

I know it’s stupid, but am I wrong for being pissed that she’d tell my spouse to lie to me?

And side note, I can’t believe I have to tell a nearly 60 year old woman that meat sitting in the fridge for two weeks is not good. I threw it away because I didn’t want her eating it and potentially getting sick.