A Hydrostatic Tester for Egg Shell Strength

IT IS perhaps paradoxical that the quality of the non-edible portion of an egg is a primary factor in the production of market eggs. However, the importance of shell strength is indicated by its frequent study. In a recent review of the subject (Tyler, 1961), 16 methods of shell strength determination were reported. Subsequently different methods have been reported by Rehkugler (1962) and Frank et al. (1964). In general, quantitative studies of shell strength have been made by either static loading of eggs, or impacting some moving object against them. None of these methods simulate the more frequent conditions of shell failure—dynamic situations involving impact deceleration of the egg. Dynamic testing of egg shell strength requires large and complex machines—drop testers—which are not ordinarily available to those interested in shell quality. However, impact deceleration can be simulated by increasing the hydrostatic pressure of the egg contents. A…