This site has some useful information about how sulfur is regulated quite differently for different foods, although the risks may be the same:
Sulfites are not allowed on red meat. Sodium bisulfite does such a good job of color fixing, that sulfited ground beef can be rotten and you canâ€™t tell by looking at it. For this reason, the FDA has an absolute prohibition against sulfites in meat. However, the rule doesnâ€™t apply to other ingredients that may be mixed into the meat. For instance, sausage may legally contain corn syrup, molasses, or wine.
SharkFish is another story. Sulfites are a preservative for fish. Theoretically, sulfited fish must carry a warning somewhere near the fish display, but Iâ€™ve never seen one.
The author goes on to describe how he has tried to find sulfur in various foods but often suspected the wrong thing, or had a hard time tracing the source(s) of his allergic reactions.