Chemical Markers for the Evaluation of Raw Material Hygienic Quality in Egg Products

The aim of this research was to study uracil, lactic and acetic acids as chemical markers for hygienic quality evaluation of raw material in liquid pasteurized egg products. Uracil, absent in sound whole egg, was formed in raw and pasteurized egg products as a consequence of high microbial contamination (>106 cfu/g) after a sufficient lag time, remaining stable at 4 °C but disappearing after 7 days of storage at 25 °C. Both lactic and acetic acids, starting from initial values of 1-7 mg/kg dry matter, presented trends similar to that of uracil; however, acetic acid never decreased during the storage of raw egg products. With few exceptions, all three metabolites were produced by Enterobacter cloacae, Escherichia coli, Morganella morganii, Serratia liquefaciens, Aeromonas hydrophyla, Pseudomonas fluorescens, Enterococcus avium, Enterococcus faecalis, separately inoculated in whole egg samples. Uracil seems to be the most sensible marker, with a suggested limit corresponding to the detectable level.