title: Development and validation of an enzyme-linked immunosorbent assay (ELISA) for quantification of lysozyme in cheese.
abstract: A competitive enzyme-linked immunosorbent assay (ELISA) was developed to quantify the amount of the preservative and potential allergen lysozyme in cheese using a commercially available monoclonal antibody against hen egg white lysozyme. The limit of detection for lysozyme in a cheese matrix amounted to 2.73 ng/mL, and the working range comprises 3.125-800 ng/mL. Intra- and interassay coefficients of variation were lower than 12%. Neither cross-reactivity with alpha-lactalbumin and human lysozyme nor unspecific interference with matrix components was observed. The recovery of lysozyme-spiked cheese ranged from 87.4 to 93.6% at four concentrations (50, 100, 200, and 400 mg/kg). The ELISA method was also compared to a high-performance liquid chromatography (HPLC) method, confirming the reliability and accuracy of the ELISA. A total of 21 commercially available cheese samples produced with and without lysozyme were analyzed with ELISA as well as HPLC. Both methods showed good agreement with a correlation index of R2=0.990.
authors.affiliation: Department of Chemistry and Pharmacy, Food Chemistry, Emil Fischer Center, University of Erlangen-Nuremberg, Schuhstrasse 19, 91052 Erlangen, Germany.
authors.forename: Nadine
authors.initials: N
authors.lastname: Schneider
authors.forename: Ingrid
authors.initials: I
authors.lastname: Weigel
authors.forename: Knut
authors.initials: K
authors.lastname: Werkmeister
authors.forename: Monika
authors.initials: M
authors.lastname: Pischetsrieder
mesh_terms: D000818:Animals; D002611:Cheese / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D009113:Muramidase / Q000032:analysis*
chemical_list: D009113:Muramidase