Sulfiting agents, sodium bisulfite and sodium metabisulfite, are used with shrimp, lobster and related crustaceans to prevent melanosis (a.k.a. “blackspot”). While sulfiting agents are very beneficial to the seafood industry, some consumers are highly allergic to sulfite residues in food. For this reason, FDA regulations state that seafood containing sulfite residues of 10 parts per million (ppm) or more must be labeled as containing sulfites. Monitoring and verification of sulfite residues are required as part of a Hazard Analysis and Critical Control Points (HACCP) program. Alert® for Sulfites is a very simple and rapid semi-quantitative test for detecting sulfite residues in shrimp.