Evaluation of chemical indices for the identification of incubator-reject eggs in egg products

The use of incubator-reject eggs (IRE) is not allowed for the preparation of egg products. However, some producers fraudulently use them for whole egg products manufacture. The aim of this research was to study the efficiency of European legislative indices (β-hydroxybutyric acid and lactic acid), uracil, furosine and organic acids for IRE detection in egg products. The results confirm the possible illegal IRE presence in egg products by selection of IRE eggs through candling and/or dilution with sound eggs. A revision of the European legislation thresholds, lowering the limits from 10 to 6 mg/kg dm and from 1000 to 600 mg/kg dm, respectively, is urgently needed. Furthermore, uracil concentrations ≥0.9 mg/kg dm should be considered a warning signal, so uracil is suggested as a future additional legal parameter. A complementing high resolution mass spectrometry screening test also identified β-hydroxybutyric acid, lactic acid and uracil as discriminative markers of IRE presence. © 2019