Cry proteins are a family of crystalline delta-endotoxins produced by the soil bacterium Bacillus thuringiensis (Bt). Biochemically they are proteinaceous toxins that bind specific insect gut receptors and form pores, a mechanism that underlies their use in biopesticides and in pest-resistant crop breeding. Discovered through early 20th-century observations of Bt’s insecticidal properties, Cry proteins were characterized and later introduced into crops in the 1990s to reduce insect damage. In human biology these proteins do not act as insecticidal agents but can be recognized by the immune system as foreign protein antigens; this immunoreactivity is what antibody-based tests like Food Zoomer measure to assess exposure and immune patterning.

Elevated IgA or IgG antibodies against Corn Cry Protein may reflect increased exposure or immune recognition of Bt-derived proteins from dietary corn or corn-derived products, or cross-reactivity with related proteins. Elevated IgA suggests mucosal (gut) immune engagement, while IgG suggests broader systemic immune recognition; both must be interpreted alongside other panel markers, clinical history, and exposure sources. Low or undetectable antibody levels generally indicate little measurable immune recognition of Cry proteins in the sample tested, which may reflect limited exposure, tolerance, or absence of sensitization. Because cross-reactivity and mixed food exposures are common, single-marker results are most informative when viewed within the full Food Zoomer pattern.

Corn Cry Protein is included to capture immune responses related to corn and Bt-associated antigens, aiding identification of immune clustering around GMO-related or corn-derived proteins. Measuring this marker alongside IgA and IgG panels helps providers distinguish mucosal versus systemic patterns and refine personalized dietary guidance based on immune signal patterns.