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Byline: Steven Pratt Chicago Tribune

Soon we may be able to put homemade hollandaise, Caesar salads, eggnog and sunny-side up eggs back on our menus.

Scientists at Purdue University in West Lafayette, Ind., have discovered how to sterilize poultry eggs in their shells without affecting the consistency of the yolk or albumen.

In the last decade eating raw eggs has been risky because they could contain Salmonella enteritis, a virulent bacteria that can cause everything from a mild stomach ache to death in susceptible people.

Though salmonella infects only about 1 in 20,000 eggs, uncooked shell eggs have been on the Department of Agriculture's hazardous food list since 1991.

The Purdue research team experimented with several pasteurization methods before devising a system that heats fresh shell eggs rapidly with microwaves then holds them at 101 degrees F for 30 minutes. In tests of eggs inoculated with salmonella, that method killed more than 1 million bacteria per egg, says microbiologist Peter Muriana, professor of food science. Naturally infected eggs seldom have bacteria counts over 100.

Salmonella are killed easily by thorough cooking, but some favorite recipes call for using raw eggs. Even some types of fried eggs are cooked only slightly. Cooking an egg causes it to coagulate and harden, making it unsuitable for some sauces such as mayonnaise. Commercial products use liquid eggs pasteurized after they have been shelled.

Working with Rakesh Singh, a food processing engineer; poultry specialist William Stadelman and graduate student Huiying Hou, the team first tried using hot water to bring the eggs up to temperature. But the microwave was much more efficient in heating the yolk without effecting the texture of the sensitive white, Muriana says.

"Kids, don't try this at home!" Muriana says. Shell eggs cooked in the microwave in uncontrolled conditions can explode and cause a real mess, he says. "Believe me, we found out."

Several Indiana egg companies are working with the scientists to adapt the process for commercial operation, Muriana says. A market study by Purdue students estimated that a full-scale pasteurizing system would add about 5 cents to the cost of a dozen eggs in the supermarket.

"In the 1980s, Salmonella enteritis adapted in a way that made them able to cause ovarian infection in chickens," Muriana says. "Now it's the No. 1 type of salmonella isolated from egg-related food poisoning outbreaks." Because a contaminated hen's ovaries can be infected, there is a slim chance that her eggs will be infected before they are laid, he says.
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Publication:Daily News (Los Angeles, CA)
Article Type:Statistical Data Included
Date:Mar 7, 1996
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