Food Sleuth: Helping people think beyond their plate

A Fresh Look at “Fresh”: Irradiation keeps your food looking perky, but what’s the cost of trading life for shelf life?

By Melinda Hemmelgarn, M.S., R.D.

Photo © Dan Hemmelgarn Melissa Hemmelgarn with tomatoes.

Of all the terms used to describe food quality, consumers rank “fresh” as most important. So if I asked you to list the attributes of a food labeled as “fresh,” would you include the word “irradiated?”

I’m guessing, probably not. However, the U.S. Food and Drug Administration will allow newly approved irradiated spinach and lettuce to bear the “fresh” label.

According to the FDA, "fresh" can be used only on a food that is raw, has never been frozen or heated, and contains no preservatives. Irradiation, preferably called “cold pasteurization” by the food industry, is allowed at low levels.

On Aug. 22, the FDA ruled that ionizing radiation could be used to treat fresh iceberg lettuce and fresh spinach “up to the maximum absorbed dose” – 4 kiloGrays – to reduce the risk of potentially dangerous bacteria, such as Salmonella and E. coli. Irradiation also kills insects, parasites, inhibits ripening and sprouting, and extends shelf life significantly.

For example, the FDA reports that irradiated strawberries stay “unspoiled” at refrigerator temperatures for up to three weeks, compared to several days for untreated berries.

We know that light, oxygen and heat destroy nutrients immediately post harvest. Irradiation further reduces vitamin content, which leads me to wonder about the nutritional merit, let alone taste, remaining in 3-week-old “fresh” irradiated strawberries or bags of greens.

The FDA says nutrient losses aren’t significant, and figures we’ll make up any lost nutrients from other dietary sources. But losses depend on the specific food, radiation dose and storage conditions.

Even though the World Health Organization and the FDA claim irradiated food is safe to eat, valid concerns have been voiced about the production of free radicals or the formation of other potentially harmful compounds during the radiation process. Ingolf Gruen, food scientist at the University of Missouri, explains that we don’t have any long-term studies of populations eating significant amounts of irradiated food.

Irradiation won’t make our food radioactive, but like all technology, the process carries benefit, risk and cost. For example, if you were the parents of a child who died from eating a hamburger or spinach contaminated with E. coli, you might understandably favor the technology at any price.
However, irradiation equipment and facilities cost millions of dollars to build and operate. Plus, with few facilities, we’ll need to add transportation costs to truck irradiated “fresh” food from processing plant to supermarkets nationwide. Consumers can expect to pick up a part of the tab at the checkout.

At the end of the day, we have to question the larger food system responsible for widespread food-borne illness outbreaks. Irradiation is not a substitute for good agricultural and manufacturing practices, or proper handling at home.

To get to the root of the problem, we must understand how ground beef, lettuce, spinach, peppers and tomatoes become contaminated with Salmonella and E. coli in the first place. That’s the philosophy behind HACCP, or hazard analysis critical control point regulation. HACCP guidelines call for tracking potential hazards and points of contamination throughout the entire food system, and correcting problems at the source.

Because both Salmonella and E. coli are found in animal feces, investigators look at critical points of contamination, including: irrigation water, proximity of crops to feedlots, slaughterhouse conditions and farm-worker sanitation.

We can irradiate the end products to kill offending organisms, but we’d be wiser to focus our resources on prevention. Be smart and know your food:

• Irradiation is voluntary; but the FDA requires all irradiated food to bear the “radura” symbol, and contain the phrase ‘treated with radiation’ or ‘treated by irradiation’ on the label.
• Irradiation labeling does not apply to restaurant foods.
• Organic foods, by law, cannot be irradiated. And of course local producers at farmers markets won’t be irradiating their great tasting real “fresh” food any time soon.

Melinda Hemmelgarn, M.S., R.D., is a registered dietitian, advocate for sustainable food systems, and Food and Society Policy Fellow. She’s based in Columbia, MO. ©Food Sleuth 2008