A hidden contaminant hunt occurs when individuals experience a reaction to an apparently safe food. It is as a result of contamination paranoia encountered in individuals who are not educated on food chemical intolerance and have not clarified their food intolerance reactions. It is generally based on a false supposition that the individual reacts to only one or two foods.

Reactions to apparently safe foods result in confusion in the individual and an attempt to discover a possible source of the suspected contaminant in the food. For example, someone who knows they react to gluten will seek to find a source of hidden gluten in the food ingredients they have eaten (e.g. "perhaps it was in the sauce", or "perhaps it was in the mashed potato"). This is a form of confirmation bias, as the result confirms the individual's current theory about food reactions, rather than seeking out a new, more likely theory (reactions to additives or natural food chemicals).

Examples of hidden contaminant hunts:

• Hidden gluten hunts
• Hidden casein hunts
• Hidden MSG hunts
• Hidden additive hunts
• Hidden carbohydrate hunts
• Hidden yeast hunts

See also, contamination paranoia.