Cold-Cracked Eggs

black and white photo of a ring

This is a ring of eggshell. Really.

Chilling keeps eggs safe from salmonella.

But chill them too fast, and the eggshells crack— invisibly—giving this stomach-churning bacteria easy entry during that warm car-ride, for instance, from store to fridge. And, according to graduate students J. Lin and T. A. Fajardo, the proposed "more restrictive Pennsylvania regulations related to cooling of eggs might potentially worsen this situation if eggs are cooled improperly."

Lin and Fajardo, with agricultural and biological engineering professors V. M. Puri and R. C. Anantheswaran, are studying the strength of eggshells to find a better cooling regime. After chilling eggs rapidly, they checked the shells by candling and with a scanning electron microscope. The microscope found "significant micro-cracks" in the shell—cracks the more common candling technique missed.

The students also developed a computer model to predict an eggshell's response to different cooling schemes. This "finite element model" required first that they know the precise force needed to crack a shell—which led them to cut and bend the elegant rings of eggshell in the photo above.

J. Lin and T. A. Fajardo are graduate students in the department of agricultural and biological engineering, College of Agricultural Sciences, University Park, PA 16802; 814-865-7792. Their advisors are V. M. Puri, Ph.D., and R. C. Anantheswaran, Ph.D., professor and assistant professor in the department, respectively; 865-7792. Their research was funded by Pennsylvania Department of Agriculture.

Last Updated December 01, 2004