Ugh help!

So currently we are living in my mother in law’s basement while we start the process to buy their house. ( just had to get the credit score up a couple points) my son is 8 months old and just recently started eating solid food, avocados are his favorite. I went to go make his avocado toast for breakfast and the avocado that I’ve been waiting to ripen was gone. Now, my mother in law is famous for throwing things away. She’s thrown away a brand new jar of peanut butter that had jelly in it from the kids that she thought was bugs, she threw $13 Parmesan cheese away that I splurged on for a dinner I wanted to make, Shes thrown away bananas I was saving to either make baby food or banana bread with, she threw away a desert I brought home from a cookout that had crushed Oreo cookies in it which she thought was “mold”. She has a habit of throwing things away that are not hers without checking with me. This morning I had no back up breakfast for my son so I was beyond irritated that she continues to throw my good food away before asking me or even mentioning it to me. She’s only 53 I know the description makes her sound like like an elderly woman. I assure you she’s just ignorant not blind or disabled. Anyway I texted her this today and when I got home she met me out in the driveway and confronted me saying what I said was very rude after all she’s doing for us by letting us live here. To be clear yes it is a wonderful opportunity she is providing for us to become home owners but we are also doing her a favor in return she’s been trying to sell her house for over 10 years but it won’t sell. I also cook dinner for 6 people every night and do the dishes afterward. I pick up her granddaughter for her almost once a week so she can go get her hair and nails done. I’ve brought her dog to the vet and cleaned up the accidents (plural) she had all over the exam room. I feel I have done more then enough to show her my gratitude and I feel her attempting to hold “you’re in my house” over my head is so unfair. At what point will she feel we are no longer indebted to her and can hold her accountable for her actions? I want to point out it’s not the avocado itself that is the issue it’s the lack of respect for other people that is upsetting me and wanting it to just stop before I snap! (Kinda kidding) Also is throwing someone’s food away before checking with the person first or this text message ruder? Someone help!