Limes are members of the Citrus genus (common types include key and Persian limes) and contain a mix of proteins, peptides, and small molecules such as citric acid and essential oils. Biochemically, proteins like profilins and lipid transfer proteins (LTPs), plus lectin-like peptides, are the primary targets for antibody binding and are the focus of food antigen testing. Historically, citrus proteins have been identified as triggers of immune responses in some people, and they are present in fresh fruit and many processed foods and extracts. In the Food Zoomer, lime is evaluated at protein and peptide levels to detect IgA and IgG binding, which provides more detailed information than single-isotype assays about how the immune system recognizes this common dietary antigen.

Elevated IgA to lime generally suggests increased mucosal immune recognition in the gut, while elevated IgG suggests a broader systemic immune response to lime proteins or repeated exposure. High levels may be seen alongside other food or additive reactivities and should be interpreted with the full panel and clinical context in mind. Low or undetectable IgA and IgG to lime usually indicate minimal measurable immune recognition, which can reflect limited recent exposure, oral tolerance, or the absence of a detectable antibody response. Single-marker results are most informative when viewed as part of the pattern across multiple foods and isotypes.

Lime is included in Food Zoomer because citrus is a common dietary ingredient and a frequent component of processed foods, spices, and flavorings. Testing lime at peptide and protein levels helps identify whether citrus-related immune activity is part of a broader pattern, supporting personalized dietary adjustments and clearer interpretation alongside other food-specific markers.