Scientists at the USDA Agricultural Research Service facility in Wyndmoor, Pennsylvania, have developed a new technique designed to destroy Salmonella in fresh shell eggs using the energy from radio waves instead of conventional hot water immersion.
The process operates by placing the egg between two RF electrodes and passing radio waves between them. At the same time the egg is rotated and sprayed with water to cool the outside. This has the effect of heating the egg from the inside, so that the dense yolk receives more heat than the more heat-sensitive albumen. The egg is then passed briefly through a hot water bath to extend the heating process and complete pasteurisation.
The radiofrequency (RF) heating process takes about 20 minutes to complete and is about three times faster than pasteurisation in hot water. This results in much less damage to the quality of the egg and less risk of overprocessing. Tests have shown that it is capable of killing 99.999% of Salmonella cells artificially inoculated into eggs before processing.
Pilot scale trials of the new process are due to begin this year, although regulatory approval will be needed before the technology can be fully commercialised. The USDA researchers hope the technique will help improve the safety of eggs used in minimally processed foods.
More information about the research can be found here.