A study published in Agricultural Research magazine has found that radio waves can kill Salmonella bacteria in raw eggs without affecting taste or texture. Since one of every 20,000 eggs produced in the U.S. has a high risk of being contaminated with the Salmonella bacteria, and since many people eat raw or undercooked eggs, this is an important finding. At least 3,750,000 contaminated eggs are sold every year in this country.
Salmonella bacteria are killed by heat. Pasteurized eggs are safer, but they can be difficult to use, especially since the egg whites do not whip to the same volume as untreated eggs. Pasteurized eggs are immersed in hot water and held at a minimum temperature for about an hour to kill the pathogenic bacteria.
In the study, scientists tested 4,000 fresh shell eggs by heating them with the energy from radio waves, followed by a brief hot-water bath. Each egg is placed between two electrodes that send radio waves through it. The egg is rotated and the shell is cooled by spraying it with water. That stops denaturing of the egg proteins, which affects taste and performance. RF heating warms the egg from the inside out. A hot water bath after the radio wave treatment helps the yolk retain heat to complete pasteurization.
Start to finish, this treatment takes 20 minutes. Tests using eggs infected with a research strain of Salmonella found that the RF-based processed killed 99.999% of Salmonella.
The new process is not only effective, but cost efficient. And RF technology is already used in the food industry. Commercial use of this treatment is about a year away. Pilot tests will begin in 2014.
