Detection of free oxygen and water vapor in fertilized and unfertilized eggs by diode laser spectroscopy-Exploration of diagnostics possibilities

Nonintrusive methods for characterizing food products are of increasing interest related to the greater awareness of food safety issues. Hen eggs are an important part in food consumption in most parts of the world. We have investigated an optical method utilizing tunable diode lasers for monitoring free gas in eggs. We show that oxygen signals, recorded around 760nm, increase steadily as eggs become older. Further, we investigated fertilized eggs, which show a quite different temporal behavior during the hatching time. The oxygen signal decreases here with time, while water vapor, recorded around 937nm, shows a steady increase. Conclusions regarding the size of the air cell and the oxygen availability in fertilized eggs are drawn. The technique might be developed for automatic control of egg freshness, as well as for assessing if eggs are fertilized or not.