Development and validation of an enzyme-linked immunosorbent assay (ELISA) for quantification of lysozyme in cheese.
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.
Schneider
Nadine
N
Department of Chemistry and Pharmacy, Food Chemistry, Emil Fischer Center, University of Erlangen-Nuremberg, Schuhstrasse 19, 91052 Erlangen, Germany.
Weigel
Ingrid
I
Werkmeister
Knut
K
Pischetsrieder
Monika
M
D000818:Animals; D002611:Cheese / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D009113:Muramidase / Q000032:analysis*
D009113:Muramidase