For others reading this thread -
The problem with sulfite is that it's not a true (IgE mediated) allergy for most people, although there are some who DO react to it with anaphalaxis. Usually it's termed an intolerance or sensitivity. Most of us just get worse symptoms as the amount of sulfite intake increases. That's why you can't just rely on a list of foods and medicines, but you have to learn your tolerance level and how much you take in with the various foods.
Sulfite gal - Can you tolerate any at all?
Rick wrote at length on the process of making corn starch. Yes, it's sulfited. I could look it up in the book to find out how much is in it, but I know it's a lot because I react to it strongly too. I can't eat gravy made with it, although I can take pills where it's used as a binder. Sulfite is often used to keep nozzels from clogging in the spray drying process of making lots of powdered foods, even if it's not added to the food for preservaitve reasons.
Another big problem for me is gelatin. Gelatin plus sulfite preservative is found in lots of immunizations, which is why I react to many of them: flu shots, pneumonia vaccine, MMR. I did get away with taking Benadryl for 2-3 days when I was forced to take the pneumonia vaccine, but it wasn't fun. I can't eat even a small serving of gelatin without getting tachycardia. The amount in capsule coatings is OK though.
Tapioca is supposed to be OK, but you may be right. I react to it a little.
Frozen lemon juice is clean.
Most tea is clean unless labeled, and some brands are preserved!
Coconut milk? Dried coconut is sulfited.
Yellow dye #5, also other azo dyes.
Shrimp can be cleaned enough for me if washed thoroughly, since it's only sprayed on.
Fresh potatoes are clean. Canned may be sulfited.
All artificial sweeteners have dextrose or maltodexrin, or the other products for diets.
Grapes and grape juice and wine are naturally sulfited.
Pork is naturally sulfited.
All cheese is supposed to contain sulfite from the action of the bacteria that makes it.
Onions and garlic.