Yellow 5 (officially tartrazine, FD&C Yellow No. 5) is the second-most-used synthetic dye in US foods after Red 40 — common in macaroni and cheese, snack crackers, citrus drinks, pickles, and many "natural cheddar" colorings. The FDA has certified Yellow 5 as safe for general use since 1969 and requires it to be listed by name (not bundled under "artificial color") because of documented allergy and asthma risk in a small subset of consumers.
The kid-specific concern is twofold. First, the 2007 UK Southampton study linked Yellow 5 (in a mix with five other dyes) to increased hyperactivity in 3- and 8/9-year-old children. That study triggered the EU warning label requirement and pushed Kraft-Heinz to reformulate Kraft Mac & Cheese without synthetic dyes (2016). Second, the FDA's own labeling requirement reflects that ~1 in 10,000 people have a Yellow 5 sensitivity that can trigger asthma attacks, hives, or anaphylaxis — much higher than for Red 40.
California's 2024 school food dye ban includes Yellow 5 (effective December 31, 2027), and it's on the EWG Dirty Dozen Food Chemicals list. As of 2026, all major US mac and cheese brands (Kraft, Annie's, Banza, Goodles) sell dye-free versions. Most "white cheddar" SKUs are dye-free by default; "deluxe" or "extra cheesy" versions often add Yellow 5 plus Yellow 6 for the bright orange color.
How to spot it on a label: Yellow 5 always appears by its specific name because of the FDA labeling rule. Look for "Yellow 5," "Tartrazine," or "FD&C Yellow No. 5." Generic "color added" without a specific dye listed usually means a natural colorant (beta-carotene, paprika, annatto), but always confirm by checking the ingredient list.