Next time same some of every food she made and send it to a lab for testing.

Stress and anxiety make me nauseous and sometimes vomit. It wod happen before tests/big games when I was a kid.

Agree with the immediate PP. You don't have much to lose by asking her what she thinks about it.

How she answers you might give you more information although if she is dysfunctional she may be angry/defensive even if she did not do anything to your food.

I'm sorry that happened to you, OP, and it sounds like there were some tough times you had to navigate as a kid. I hope you have found healing.

Have you considered asking her what she remembers of these episodes and what she thought caused them? I think her reaction might tell you a lot.

I think it’s highly possible!
Unfortunately there are many more crazy people than we think, and most of them are very good at masking their craziness

I don't wash my hands before I cook and neither my husband or myself ever get sick. Judge away. Oh- and I use the same cutting board for everything.

I’m more likely to suspect improper hygiene or food handling. Alternatively, you were a kid in school. Classrooms are cesspools of bacteria and some people fight them off better than others. I had a job a few years back where I got sick every single Monday (my day off) for weeks. Never happened since. Could have been stress, could have been eating food that sat out too long, more likely was the dirty gross environment. (I was a bank call center—everyone in one big open room. Bacteria and virus central.)

I guess anything is possible, but I also experienced vomiting like that about once a month when I was in college. After I left college, it never happened again. I attribute it to stress, lack of sleep and, for a time at least, taking birth control pills.

Thank you for all the suggestions, everyone. I am still a fan of Lean Cuisines and sometimes eat chicken hot dogs without any problems. Perhaps different additives were used when I was young, but I don't have a problem now with them. As a child, I never got sick to my stomach after eating at a restaurant or at a relative's or friend's house, just my own home.

PP You mentioned frozen dinners and hot dogs after I posted. You might be allergic to a particular preservative.https://www.foodallergy.org/resources/food-additives-and-allergies/intolerances

Op that is strange. She could very well be putting something in your food.

I also briefly considered a food allergy, but I have not experienced that as an adult and have lived in multiple countries and eaten all kinds of foods and types of cuisines. I have not had a similar reaction.

My husband always said meat mead his stomach hurt and that he vomits a lot randomly. Then we moved in together and I almost never saw him vomit. But I HAVE seen his mother navigating her kitchen with unwashed hands while handling poultry. I'm pretty sure it was her lack of food safety. Is that a possibility?

Yes, she did show malicious behavior towards me, particularly from First Grade onwards. That is partly why I started considering whether it could be intentional. Perhaps it was just really bad cooking practices that only affected me and not my parents, but that seems odd.

Is there any particular recipe that your mom made once a month? Could it have been an allergy of some sort? Some people are allergic to certain spices. See https://www.nyallergy.com/spice-allergy/#:~:text=Spice%20allergies%20occur%20in%20up,to%20cause%20an%20allergic%20reaction.

If a spice like tumeric caused your reaction, it may have just stopped in college because your college dining hall didn't use it.