Rapid and sensitive quantitation of hen egg-white lysozyme in foods using paper sensor

Hen egg-white lysozyme (HEWL) is commonly used in food preservation and as a substitute for sulfur dioxide in wine production and to prevent late blowing defects in cheese production. However, HEWL is an egg allergen that can cause severe allergic reactions in allergic individuals after accidental ingestion. Therefore, in order to prevent life-threatening health problems caused by consumer allergies, we developed an extremely specific gold immunochromatographic assay (GICA) tolerant to matrix effects for the qualification and quantification of HEWL in food products. First, we prepared a monoclonal antibody (mAb) specific for HEWL. By optimizing the parameters of the sandwich enzyme-linked immunosorbent assay, we performed mAb interaction analysis. We developed GICA strips for the determination of HEWL in foods by combining mAb with colloidal gold. Additionally, considering the complex matrix of foods, standard curves for HEWL-negative milk, cheese, and grape wine samples were established to minimize matrix effects. The calculated limits of detection for the determination of HEWL in milk, cheese, and grape wine were 21.12 ng/mL, 0.89 μg/kg, and 1.61 ng/mL, respectively. The recovery rates of the HEWL-spiked samples were 99.16 %-102.25 %, which were comparable to the HPLC results. Thus, we have successfully developed a rapid, sensitive and specific GICA method for the qualification and quantification of HEWL in milk, cheese and grape wine.