An Agricultural Research Service (ARS) scientist and his colleagues have developed a technology that rapidly pasteurizes eggs and could sharply reduce the number of illnesses caused each year by egg-borne salmonella bacteria.

The device — invented by David Geveke, a chemical engineer at the ARS Food Safety & Intervention Technologies Research Unit in Wyndmoor, Pa. — uses radio frequency (RF) waves to heat eggs and reduce salmonella without damaging egg whites.

Salmonella is associated with eating undercooked eggs or the raw eggs used in Caesar salad, eggnog and Béarnaise and hollandaise sauces, etc. Salmonellosis can cause diarrhea, stomach cramps and fever. Infants, preschoolers, pregnant women and the elderly are especially susceptible. Because of this, pasteurized eggs are often marketed to nursing homes and other institutional kitchens. However, overall, less than 3% of the 74 billion fresh eggs produced and sold to U.S. consumers each year are pasteurized, ARS said.

Current pasteurization methods involve immersing eggs in hot water (130-140°F). The process takes about an hour and adds about $1.50 to the retail price of a dozen eggs. It also can cause proteins in the heat-sensitive egg whites to break down and coagulate during cooking, ARS noted.

The patented RF process is faster and ensures that the protein-rich yolk gets more heat than the egg white. It also should lower the cost of pasteurization — and the price of pasteurized eggs on store shelves. If pasteurized eggs become less expensive and more abundant, more people are likely to choose them, and fewer people will get sick, Geveke said.

RF technology is already used to reduce pathogens in almonds, spices, wheat flour and other food products.

Geveke and his colleagues have published results showing that the RF treatment reduced pathogen levels by 99.999%, which is comparable to eggs pasteurized in hot water. The entire process also took about 20 minutes, making it almost three times faster than using hot water.