A rapid method to determine bacterial contamination on hatching eggs. 2. Correlation of the optical-density measurements after incubation to bacterial counts on hatching eggs.

The suitability of using optical-density (OD) measurements after a 6-h incubation period to determine bacterial contamination on hatching eggs was evaluated. A total of 154 hatching eggs, from five different flocks, were examined visually and bacterial counts and OD measurements of egg washings after 6 h of incubation at 37 degrees C were carried out to determine the levels of bacterial contamination, and these results were compared. A relationship between the OD measurements of egg washings and the log of the bacterial plate counts, was demonstrated. The OD measurements provide accurate and quantitative information to detect bacterial contamination on hatching eggs, as they are simple to perform, repeatable and reliable.