Systems and methods for a handheld food additive detector are described. In one aspect, the food additive detector includes a test strip treated with or comprising chemical(s) reactive to at least one target characteristic (e.g., additive(s), compound(s) created as a result of stale/old food, etc.). Responsive to a food sample being placed on the strip, a sensor operatively coupled to the handheld device measures one or more of the strip characteristics (e.g., color, contrast, etc.) resulting from placement of the sample on the strip. The device analyzes the sensor measurement value(s) to determine presence, quantity, concentration, percentage, relative amount, and/or so on, of the target food additive(s), or other characteristics of the food that pertain, for example, to freshness or staleness. Results of the analysis are presented to a user.