The screening and/or identification of different types of irradiated eggs by analyzing photo-stimulated luminescence and thermoluminescence

Photo-stimulated luminescence (PSL) and thermoluminescence (TL) analyses were done to screen or identify irradiation treatment of ostrich, duck, hen and quail eggs. These eggs were gamma-irradiated at 0, 1, 2 and 3 kGy and the eggshells were used for PSL and TL analyses in a powdered form. The PSL results showed that all the non-irradiated control samples had photon counts (PCs) less than the lower threshold value (700 counts/60 s). Some of the irradiated samples like ostrich and duck, however, showed PCs higher than the upper threshold value (5000 counts/60 s), and the other irradiated samples were between the lower and upper values (700–5000 counts/60 s). Photon (PCs) less than the lower threshold value (700 counts/60s). Although the TL glow curves which originated from the calcite mineral present in eggshells, which were confirmed by X-ray diffraction spectroscopy. The intensities of the first glow curves (TL1) obtained from the egg shells were less intense as compared to that of quartz or feldspar that are usually present on the surface of the food as contaminants. The intensity and shape of the first glow curve (TL1) as well as the glow curve ratios (TL1/TL2) based on a normalization step, enabled discrimination between the control and irradiated eggshells by using natural bio-inorganic minerals.