What are category-level contaminant flags?
Short answer
A category-level contaminant flag reports that a food category is monitored by regulators for a specific contaminant — cadmium in cocoa, methylmercury in large fish, inorganic arsenic in rice. It is anchored to FDA monitoring programmes and applies to the category, never to the individual product in your hand, which no app has tested.
What the flag actually says
It says: regulators monitor this food category for this contaminant, at these levels, for this reason. It does not say the tin of tuna you scanned contains mercury above any threshold. No consumer app has laboratory results for an individual package, and any app implying otherwise is overstating what it knows.
Because the claim is category-level and precautionary, it is capped at a caution in the score — it can lower a score but never drive it to the bottom on its own.
Examples of the anchoring
- Inorganic arsenic in rice-based foods — FDA action level of 100 ppb for infant rice cereal
- Methylmercury in large predatory fish — FDA/EPA joint advice on shark, swordfish, king mackerel, tilefish
- Cadmium and lead in cocoa and dark chocolate
- Heavy metals in baby and infant food — the FDA Closer to Zero programme
- Acrylamide in fried and roasted foods, including chips, fries and coffee
- PFAS in grease-resistant food packaging
How to use it without panicking
Contaminant flags are most useful as a variety prompt: eat different fish rather than the same large predatory one weekly, vary grains rather than eating rice at every meal, and pay closer attention for infants, who eat a narrow diet at a low body weight. That is the same advice regulators give, and it is the intended reading of the flag.
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Last updated 26 August 2026.
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