Detection of hen lysozyme on proteic profiles of Grana Padano cheese through SELDI MS ToF high-throughput technology during the ripening process

Lysozyme is used in cheese manufacture in order to prevent blowing in cheeses caused by Clostridium tyrobutyricum. Being an egg derivative, the presence of lysozyme must be included on the label for residual allergenic risk (2003/89/CE). The aim of this study was to evaluate the presence of lysozyme on proteic profiles of typical Italian cheeses such as Grana Padano through surface-enhanced laser desorption/ionization time-of-flight mass spectrometry. The proteolytic activity of ripening (from 0 to 24 months), confirmed by a decrease in casein, did not influence the intensity of lysozyme peaks. Furthermore, ripened Grana Padano cheese could be differentiated on mass profiling from immature Grana Padano by the presence of particular signals that are probably related to casein proteolysis.