I want to add a little more about just how careful some IBS people may need to be.
Conventional poultry not only poses a challenge because of the antibiotics and harmones it contains, but also because food manufacturers sometimes inject it with milk products to make it taste better. Butterball turkey is an obvious example of this. But there are other less obvious examples. I've discovered, for example, that most restaurants purchase poultry that has been injected by milk products before it is cooked.
I've totally given up on buying conventional poultry. The last time I tried, I boiled and boiled it and then ate a small piece and (like the times before) I got stomach cramps. I tried another piece the next day with the same result. I had purchased the poultry from one of the best and highest quality food stores in Toronto.
The next day I went to the health food store and bought organic chicken and I've never looked back since. I feel fine after eating organic chicken. Actually the chicken I purchase is not officially "organic." However, it contains no additives and has been raised without harmones and antibiotics. I believe an organic certification is difficult for poultry farmers here in Canada to obtain so some don't apply for it even though their poultry is "organic."