Immunological detection of denatured proteins as a method for rapid identification of food residues on archaeological pottery

Our understanding of human diet in different periods of history can be enhanced by investigating direct evidence represented by accidentally preserved food remains found on pottery. So far, this task has been accomplished by the application of gas chromatography/mass spectrometry, often in combination with stable isotope analysis. These methods require specialised laboratories and their cost prevents wider penetration into the daily practice of archaeology and related disciplines. We have tested commercially available immunochromatographic kits for this task, which are designed to detect contaminants and allergens in the modern food industry. Unlike the previously published studies on archaeological material, we focus specifically on the identification of damaged and denatured proteins, which correspond better to the state of preservation of proteins in desiccated and carbonised organic residues that have survived from antiquity. We report the first successful qualitative detection of bird eggs, animal meat, milk (and species of origin), and to some extent also the presence of plant food, especially cereals and hazelnuts. The immunoassay is a methodology that is well suited for use in the field and resource-poor environments, so it is ideal for most archaeological excavations and museums. With necessary caution, the results can be used as a proxy for human diet in the past and reconstructions of anthropogenically modified environments.