The Department of Biosystems Engineering, at Zhejiang University, Hangzhou, China, has an ongoing scientific interest in lightly tapping quasi-spherical food items and observing the results. So far they have investigated : Pears, Peaches and Melons. And, surprisingly perhaps, the latest under the hammer are hens’ eggs. For it has been discovered that when exposed to a “light mechanical impact” the vibrations of cracked eggs and intact eggs are considerably different. Some of the resonant frequencies are higher for the cracked eggs, whereas the dominant frequency is lower for intact eggs.
“The result was found that the acoustic impulse response method can distinguish between intact egg and cracked egg. This research provides a technology detection of cracked egg.”
Results are published in Innovative Food Science & Emerging Technologies, July 2010, Pages 520-525.
Note: The same university department has previously developed an ‘Electronic Nose Test’ which can also successfully detect cracked eggs (after one or two weeks of storage).