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United States Department of Agriculture

Agricultural Research Service

Title: MEASURING HAUGH UNITS

Author
item Jones, Deana

Submitted to: National Egg Quality School Proceedings
Publication Type: Proceedings
Publication Acceptance Date: April 26, 2002
Publication Date: March 1, 2003
Citation: Jones, D.R. 2003. Measuring haugh units. National Egg Quality School Proceedings. p. 288-289.

Technical Abstract: The Haugh unit is revered as the "gold standard" for interior egg quality determination. This method was developed by R. Haugh in 1937 and is based on the relationship of egg weight and height of the thick albumen. USDA Agriculture Marketing Service (AMS) have published specific guidelines for Haugh unit readings and egg grades (AMS 56.210). Haugh units are determined with the aid of a micrometer, balance, and level, flat surface (such as an egg break-out table). A break-out table can be useful during measurements because the mirror allows the operator to determine exactly when the micrometer comes in contact with the thick albumen surface. The selection of the sample site on the thick albumen surface is important. Care should be taken to prevent contact with the chalazae or placement of less than 1 cm from the yolk. Both of these conditions can lead to elevated to values. The operator needs to take care when cracking eggs for analysis to ensure the thick albumen is not broken. There are also more technologically advanced instrumentation that connect to a PC and allow for "real time" results.

Last Modified: 9/2/2014