Differentiation of eggs from organic and conventional production systems using fluorescence excitation spectroscopy (FES)

ABSTRACT The decay curves of the delayed luminescence of egg yolks after excitation with white, yellow and blue light were investigated, using fluorescence excitation spectroscopy (FES), and the relationships to the origin of the eggs were examined. FES measurements were done by exciting the sample with light of defined wavelengths, representing the colours white (w), blue (bl) and yellow (ye), and the subsequent photon emission was detected. A total of 147 samples (each sample consisted of 10 eggs) were analysed, which originated from samples collected directly from the farm as well as from retail markets. Classification by partitioning and Tukey HSD tests were used to show differences between the origin of the eggs. It was shown that the induced emission of the conventional eggs was different compared with that of the organic eggs, which was reflected especially in the long-time emission parameters R40-w and R80-ye/bl, with lower values for conventional samples. Classification was possible with the parameters R40-w and R80-ye/bl, allowing correct classifications of 91.8% and 95.9% of the samples, respectively.