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Extension > Source - Winter 2007 > How safe is your food?

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How safe is your food?

Your nose doesn't always know

How often have you pulled something from your refrigerator, sniffed and wondered, "Is this still OK to eat?" The smell is not always the answer. In recent months, fresh produce has been linked to many E. coli outbreaks. That's because fruits and vegetables consumed raw aren't subjected to the same safety net of proper cooking temperatures like meat and other heated foods. But don't give up on raw produce just yet. University of Minnesota Extension researchers and educators are hard at work, finding new ways to keep your food safe.

Food that appears to be spoiled

In a near-perfect world, scientists could develop a method to kill harmful bacteria without changing the taste of food or harming the environment. This near-perfect world exists on the University of Minnesota's St. Paul campus. That's where Joellen Feirtag, Extension food scientist, has been experimenting with a water-based electrochemical activation system that disinfects and cleans food.

While electrolyzed water systems are not new, this system, developed by a team of Russian scientists, is unique because it produces a pH-neutral solution that won't cause deterioration or off flavors when sprayed on food. The system is environmentally friendly; its only outputs are water and salt.

"The results we're seeing are phenomenal," Feirtag said. "It's killing all bacteria and viruses. It even kills avian flu and anthrax spores."

Feirtag sees great potential for the system and is working to get it into the food industry. The solution can be sprayed directly onto foods such as lettuce, destroying bacteria like the E. coli strain responsible for the spinach outbreak. "This system could be used from the farm to the retail market-for irrigation in fields, washing in processing plants and misting in grocery stores," Feirtag said.

In another University lab, food scientist Ted Labuza focuses on the time it takes the disease-causing bacterium Listeria monocytogenes to grow to dangerous levels in foods such as deli meats and hot dogs. The way Labuza sees it, food labels with phrases like "best if used by" and "sell by" are not good enough. Current labels are based on consumer preference and quality standards like taste, texture and color. Labuza and fellow food scientists want to see those labels based on safety standards like temperature history and potential levels of disease-causing bacterium.

Labuza helped develop a system that allows manufacturers to evaluate the safety of their products. Thanks to Labuza's mathematical equations, small chemical and electronic food label tags can track the time-temperature history of food products during their journey from processing plant to supermarket.

Labuza proposes using labels with statements such as "use by the date indicated, unless the time-temperature history tag turns red." Food companies can use these tags in Europe, but it will be up to the U.S. government to mandate their use to help improve food safety in the United States.

Keeping your fast-food and restaurant meals safe

Minnesota requires that food service establishments employ a certified food manager (CFM), someone who has taken and passed food safety education training and a certification exam. Extension offers courses to help restaurants meet the state requirements. Since 2003, close to 5,000 managers and food service workers have participated in two Extension courses, ServSafe and Serve It Up Safely.

For more information, see

Singing and hand washing go hand in hand!

washing hands

Conducting University research on local growers' farms gives Extension soil scientist Carl Rosen and engineer Jerry Wright the best scenario for studying high tunnels in action.

The U's Central Region Sustainable Development Partnership funds the research.

The quick, "get your hands wet, add a little soap, rinse and dry" routine just doesn't get the job done, advises Joellen Feirtag, Extension food scientist.

"Too many people don't realize they're not getting their hands completely clean," Feirtag said. "If you aren't good at washing your hands, you're helping to spread bacteria. And that can make you sick."

Her advice for good hand washing: pick any 20-second song, such as the "ABC Song," "Happy Birthday" or "Twinkle, Twinkle Little Star." Start singing, and continue washing until you're done singing.

Feirtag says kids and adults most often forget places with ridges or calluses, fingernails, and wrists.

For the Flynns, the biggest challenge has been explaining their growing system to customers. "I bring pictures with me every year because I get the same questions, ‘Who do you buy your cucumbers from?'" said Dallas Flynn, who sits on the board of directors for the Minnesota Farmers' Market Association. "The beauty of it is when they find out it's locally produced by me. They love that."

Extension Food Doctor Francisco Diez answers your questions

Doctor Francisco Diez

Q: If my leftovers don't smell bad, can I still eat them?

A: For cooked leftovers, the recommended range is three to five days. Some microorganisms can grow at low temperatures in the refrigerator. Changes in flavor, taste and smell reflect the fact that bacteria and other organisms are growing. But don't wait for that to happen. Toss leftovers after three to five days.

Q: My bag of veggies says it's "triple-washed." Why do I need to wash it?

A: Such claims are not regulated. No one checks whether the product had three washings or whether those washings were effective. To remove soil, wash under running water.

Q: How do I get rid of bacteria on my vegetables?

A: Two alternatives can help you get rid of 99 percent of bacteria: soaking your veggies in a solution of water and household bleach (1 tablespoon per gallon of water) or a solution of water and at least 40 percent vinegar. Your best line of protection is to cook fresh vegetables

Q: Can I store my restaurant leftovers in take-home containers?

A: The containers you get in the restaurants were designed for transportation, not storage. If you're not going to eat the food the next day, move it to your own food-storage container. You never know how those containers were handled in the restaurant. And, styrofoam is not made for long-term food storage. The plastic material can leach into food if the food is exposed to the container for a long time.

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