Raisins

Fresh grapes are generally considered low-to-moderate in histamine and appear on some histamine liberator lists — drying them into raisins amplifies the concern considerably.

• Concentration effect — a small handful of raisins represents a lot of grapes in a tiny volume, so whatever histamine or liberating compounds are present become meaningfully more concentrated than in fresh grapes

• Sulfites are nearly universal in commercial raisins — sulfites help preserve color and shelf life, and they're one of the more reliably problematic additives for people with histamine sensitivity

Unsulfured raisins exist but are less common — fresh grapes tend to be a more manageable option if you want that flavor.