by Lauren Kern
You might not see bugs and bacteria on fresh fruit and vegetables, but they’re there. Texas A&M food engineers are experimenting with new technologies to eliminate these threats to keep our produce safe and healthy.
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Food engineering graduate student Carmen Gomes searches for new ways to keep fruits andvegetables safer and fresher for longer. Methods include irradiating the produce with a burst of energy and novel packaging.
Despite rigorous national standards, in 2006, spinach infected with Escherichia coli made it to consumers undetected, and more recently tomatoes hit the market with a rare form of Salmonella Saint Paul. According to the Centers for Disease Control andPrevention (CDC), more than 1,000 people in the United States were infected, sending almost 300 to the hospital and possibly contributing to two deaths.
Many Americans assume fruits and vegetables sold in supermarkets are safe: wholesome foods that are good for us and won’t make us sick.
This can be a deadly assumption.
Food engineering researchers at Texas A&M are perfecting a method toensure the safety of fresh produce: electron beam, or e-beam, irradiation. Electron beam irradiation kills disease-causing organisms that conventional decontamination methods can’t touch. “Irradiating produce reaches bacteria inside the vegetables, not only the organisms that are on the surface,” says food engineer Rosana Moreira, professor and assistant department head in Texas A&M’s Department ofBiological and Agricultural Engineering. “It kills bacteria without damaging produce or making the product unsafe to eat.” e CDC says that food irradiation holds great potential for preventing many foodborne diseases in meat, poultry, fresh produce and other foods without harming the nutritional value of food or making it hazardous to human health.
“Irradiating produce reaches bacteria inside thevegetables, not only the organisms that are on the surface,” Moreira says. “It kills bacteria without damaging produce or making the product unsafe to eat.”
CT scans of food items: 1) raspberries 2) broccoli ﬂorets 3) an egg 4) a whole chicken These 2-D images are used to calculate the smallest dose of irradiation needed.
Moreira and Elena Castell-Perez, also afood engineer and professor in biological and agricultural engineering, are working with a team of 11 graduate student researchers to calculate the best methods of using electron beam irradiation to eliminate dangerous bacteria and maintain the nutritional content of fresh produce. Electron beams are streams of high-energy electrons produced by an electron gun. e gun generates the beams by usingsomething found in every home, a larger version of the tube that shoots electrons into your TV screen. e beams are not radioactive, and they can be turned on and oﬀ like your TV or a ﬂashlight. is process is conducted using linear accelerators (LINAC), a 10MeV linac located at the National Center for Electron Beam Research and a 1.25 MeV accelerator located in the Hobgood Building.
“But irradiatedfood is completely safe, and in some ways may be better than food that has not been irradiated.”
Chemical vs. e-beam
Almost all fresh fruits and vegetables sold commercially in the U.S. are treated with chemicals before reaching grocery stores. Although beneﬁcial for eliminating many contaminants, some of the chemicals used have been found to leave residues that can become harmful once inthe consumer’s hands — for instance, when cooking fruits and vegetables at high temperatures, common in the home canning process. And chemical cleaning reaches only bacteria on the surface of the produce, and it may not even eliminate all of that. Carmen Gomes, a food engineering Ph.D. student who works with Moreira and Castell-Perez, says food irradiation has several advantages over chemical...