I've had the food triggers myself. When I relapsed my anxiety became so high due to a med I had just started that eating any food made me panic because I would feel the changes in my body. It took me about 3 weeks of intent staring at the TV power button whilst eating, a distraction technique I had read about, before I seemed to find a decrease in this trigger. It still took ages to work through the fears about trying new foods but at least the high anxiety had died away a lot.
Prior to all this, when I was working up to my first real breakdown, I used to take lots of exercise supplements for my weight training. All legal stuff. I added a new one that turned out to be just too strong for me, it was for advanced trainees only, and it gave me a huge adrenaline rush and my chest was pumped.
After that I went into my full breakdown and started to be afraid of anything in the way of supplements or meds. I wouldn't even take vitamin C, which is as safe as it gets. I wouldn't take paracetamol. I even stopped taking my asthma medication and ended up having a mild asthma attack that forced me to restart them.
Getting past this is still a work in progress but I have worked through lots of things to be confident with taking them. It took time, a lot of months to expose myself to different supplements to extinguish the fear gradually, but I got there.
It wasn't about poisoning for me, it was just the change in my body and the lack of control over something being ingested.