X-ray technology is effective in killing bacterial pathogens in leafy greens without causing undesirable changes in product quality, say Michigan State University (MSU) researchers.

Jane Byrne writes on Foodnavigator.com that Bradley Marks and Sanghyup Jeong claim X-rays can kill bacterial pathogens such as E. coli O157:H7 and Salmonella on the most delicate vegetables, as well as extend their shelf life.

Irradiation from other sources has been used for years to protect ground meat and other products. The process exposes foods to ionizing radiation that kills insects, molds and bacterium and the technology can kill up to 99% of pathogens.

The U.S. Food and Drug Administration (FDA) recently published a final rule allowing irradiation of lettuce and fresh spinach; the technology can already be used with other foods such as spices, poultry and shellfish including oysters, clams and scallops.

The MSU researchers said that they have been applying a higher dose than that used for medical X-ray imaging, but a lesser dose than that used by competing irradiation methods.

“That means less protective shielding is necessary, so the equipment is more compact and food companies can install it at their processing plants,” claim the researchers.

Peter Schoch, CEO of Rayfresh Foods, claims the potential for widespread contamination is compounded by the mingling of greens from different sources in processing plants. He says food irradiation based on the use of gamma rays from radioactive material or machine-generated electron beams tends to cause cellular damage and visually degrade food, whereas irradiation using X-rays promise a gentler, more scalable approach.

Schoch says his company recently won its first contract to build an X-ray machine to treat ground beef for Omaha Steaks.

According to Global Industry Analysts, the world food irradiation market is predicted to exceed $2.3 billion by 2012. Analysts say the U.S. is the single-largest market for food irradiation, accounting for an estimated 32% of global demand in 2008, with Asia and Latin America seen as hot growth areas in the future.
-- Foodnavigator.com