Effect of testing temperature on internal egg quality measurements

The objective of this study was to determine the effect of egg testing temperature on quality measurements of shell eggs. The quality measurements compared included 3 Haugh unit (HU) devices (electronic Haugh, tripod Haugh, and Haugh meter), egg weight, albumen height, albumen width, albumen index, yolk width, yolk height, yolk index, percentage of thin albumen, and vitelline membrane strength at 3 temperatures of 5, 13, and 23 degrees C from 2 strains of laying hens (Hyline W36 and Bovans White) at 2 storage times. The HU measurements averaged 72.44 at time zero and 59.99 at 7 wk. At 7 wk for all devices, HU values decreased 6 units with increased temperature (P < 0.05). The electronic Haugh and tripod Haugh devices gave equal measurements for all testing conditions. The Haugh meter gave equal values at 5 degrees C for fresh eggs but lower HU at higher temperatures and 7 wk storage. Thus, it is recommended that egg testing temperature be reported when HU are measured. Coefficient of variation generally increased for all HU methods with increasing temperature. Although there was a proportionately different amount of thin albumen detected between the strains of laying hens, no significant difference was seen in HU. From the evaluated methods for measuring quality, the electronic Haugh, which electronically measures albumen height and calculates HU, provided the lowest coefficient of variation, was sensitive to quality loss, and gave the highest quality measurement (5 degrees C).