Abstract
A detailed study of the condition of eggs was performed using tunable diode lasers to monitor free gas in hen eggs. We detected oxygen and water vapor signals from 13 unfertilized eggs and studied the growth of the egg air cell over a time period of 3 weeks. We also studied the gas exchange through the egg shell, which is of particular interest for fertilized eggs. Four fertilized and five unfertilized eggs were followed over 3 weeks, the hatching period for hen eggs, and significant variations were found both in time and for the two types of eggs. Our results indicate that the techniques could be developed for automatic control of egg freshness, as well as for monitoring the hatching progress of fertilized eggs.