Poultry and eggs are easily contaminated by pathogens and irradiation is a food preservation method .For fresh eggs, EFSA recommends doses ≤3kGy sufficient to inactivate Salmonella. Many countries claim the availability of rapid methods to detect the occurred treatment. The aim of this study was to test physical and chemical methods for the detection of irradiated eggs.

Tests were carried out on unirradiated and irradiated eggs purchased at local markets. Irradiation was performed in the range 0.5-5 kGy using X-ray irradiator. Thermoluminescence-TL and photostimulated luminescence-PSL were performed on silicates contaminating the egg surface as well as on the crushed shells. The headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME/GC-MS) was employed to determinate 2-dodecylcyclobutanone as irradiation marker.

As for physical techniques, the best results were obtained using the shells as the quantity of silicates was rather small due to the cleaning treatment before marketing. The results obtained by TL technique were particularly satisfactory, providing different glow curves for irradiated samples. PSL method was not always able to identify irradiated from non-irradiated samples due to lower sensitivity. HS-SPME/GC-MS allowed the detection of 2-DCB at the minimum dose of 0.5 kGy.

In conclusion, three analytical methods were applied to the eggs non-irradiated and irradiated at different doses. Among them, those based on the TL and HS-SPME/GC-MS techniques provided the best results with correct classifications.

Ijaz A. B. et al. Food Contr. 19 (2008) 587–591.

Campaniello M, et al. Int. J. Food Sci. Tech. 55 (2020) 961–969.

Project IZSPB 05/23 RC, financed by the Ministry of Health