Monday, December 11, 2023

Researchers creating new ways to pasteurize eggs

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By Dennis O’Brien

Special to Poultry Times

BELTSVILLE, Md. — A USDA 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 and Intervention Technologies Research Unit in Wyndmoor, Pa., uses radio frequency (RF) waves to heat eggs and reduce Salmonella without damaging egg whites. Partners include Christopher Brunkhorst, an electrical engineer from the Princeton Plasma Physics Laboratory in Princeton, N.J.

Salmonella is associated with eating undercooked eggs or the raw eggs used in Caesar salads, eggnogs and Béarnaise and hollandaise sauces. Salmonellosis, as the infection is known, 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. Yet overall, less than 3 percent of the 74 billion fresh eggs produced and sold to U.S. consumers each year are pasteurized.

Current pasteurization methods involve immersing eggs in hot water (130 degrees F to 140 degrees 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.

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 says.

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

Geveke and his colleagues have published results in the Journal of Food Engineering showing that the RF treatment reduced pathogen levels by 99.999 percent, 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.

USDA estimates that pasteurizing all U.S.-produced shell eggs could reduce the number of egg-borne salmonella illnesses by up to 85 percent, or more than 110,000 cases a year.

Geveke is working with a commercial partner on plans to market the technology to egg processors.

Dennis O’Brien is a public affairs specialist with the USDA Agricultural Research Service in Beltsville, Md.

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