WEST LAFAYETTE, Ind., Sept. 2 (UPI) -- With millions of eggs recalled in the United States for possible salmonella contamination, a way to create ice within shells shows promise, researchers say.
Purdue University food-science Professor Kevin Keener has spent a decade working on a system that uses carbon dioxide to create a thin layer of ice inside eggs shortly after they are laid, the Toronto Star reported Thursday.
"Currently, when eggs are put into pallets they are cooled using traditional refrigeration," Keener said. "Eggs near the center of the pallets can take up to six days to cool to the point where salmonella can't grow."
The long cooling process allows roughly 1 in 20,000 eggs to become contaminated with salmonella, Keener says, which leads to 130,000 shell egg-related salmonella infections in the United States each year.
In Keener's system 10 dozen eggs at a time are placed in a chamber the size of a conventional oven immediately after they are laid.
Liquid carbon dioxide is then sprayed inside and the chamber is rapidly cooled to minus 110 degrees Fahrenheit.
The CO2 that fills the chamber passes through the pores in each egg's shell. When a thin layer of ice forms inside, the eggs are taken out.
"We cool them in 2 to 5 minutes, instead of six days."
And, Keener says, the technique adds at least four weeks to the shelf life of eggs.