3. Can I rely on food labels? Short answer: no, may be. The FDA does have general guidelines. In 2006, the Food Allergen Labeling and Consumer Protection Act became in effect. Eight of the commonest allergens were required to be listed on the labels if those eight allergens were even potentially present at any stage in the manufacturing of any ingredient in that food. The intent was to help patients avoid them. The eight allergens are: milk, eggs, fish, shellfish, tree nuts, nuts, wheat, and soybeans. This has been effective. BUT if a patient is allergic or has adverse reactions to other substances in foods, food labels can NOT be relied on. Items for food processing, such as gelatin, do NOT have to be listed on labels, per the FDA, because they are deemed to have no effect on the food or be present in only trace amounts. Unfortunately, trace amounts can be enough to trigger allergic reactions in highly sensitive individuals.
This is not to say that processing aids are not regulated. They are and are defined clearly by such bodies as the European Union, FDA, and the Canadian government.
6. Is it completely safe to eat in restaurants if they post or list all of their ingredients? No, and this is not a knock against restaurants or food preparers. The issue is called cross contamination, which means the transfer of harmful substances to foods. This is inadvertent, but still a risk that depending on the severity of reactions must be considered.