Iradiation helps ensure food safety

Irradiation helps ensure food safety

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By Jennifer Bremer

Ensuring the safety of the food supply is a pertinent part of the food chain. Research with irradiation has led to improved safety at the pre-consumer part of the chain.

Iowa State University animal science Professor Dennis Olson has been studying irradiation of meat and other foods for more than 15 years. He directs Iowa State's Linear Accelerator Facility, which is one of only two commercial-sized irradiation facilities for food research and demonstration on a U.S. university campus.

"Our facility here opened one month after the Jack-In-the-Box incident in 1993," he said. "So our immediate studies were done on eliminating the risk of E. coli in beef."

Olson is an expert in food safety and particularly meat safety. The U.S. Food and Drug Administration has allowed the irradiation of meat to control pathogens since 1997, and since 1990 in poultry. But he said it was a long process before that and they continue to work on ways to make irradiated beef more accepted at the grocery store counter.

"People need to understand that irradiating beef isn't going to harm them at all but, in fact, it makes it safer and protects it more from illness-causing pathogens," he said. "But consumers must still understand that proper food handling at home is a must, also."

The process

The entire process of irradiating food products depends on the amount of time needed and exposure to the non-radioactive electron beams. The items are placed in a cart, which then moves into the linear accelerator and follows along a conveyor until it reaches the spot of exposure.

The facility is built with several safety devices to ensure no human exposure to the rays.

The process can kill most microorganisms in the food and decreases the chance of foodborne illnesses.

Ground beef has been an important part of Olson's research through the years because of the amount of surface area and the possibility of contamination in the ground product.

"Ground beef comes from so many different areas of a carcass and has an extremely higher risk for pathogens to be present," he said.

Olson said the use of irradiation somewhat mirrors the adaptation of pasteurization in milk.

"It wasn't until the public health officials said we needed milk to be pasteurized that it became a widely used practice," he said. "The problem is, enough people are going to have to become ill for the health professionals to realize irradiation is beneficial for eliminating the risk in so many different foods.

"While irradiation can help get rid of the microorganisms, consumers also need to use proper food handling procedures to prevent recontamination in the kitchen," he added.

Irradiation not only kills microorganisms, but also increases shelf life by nearly two-fold. Fresh meat products that normally last 14 days can last 28 days with irradiation. With a new process using carbon monoxide, researchers have found an increase in shelf life of up to 55 days. This process is intended for selling meat at convenience stores where the supply isn't leaving the shelves as fast, according to Olson.

Irradiated beef

While irradiated meat is safe, it has also had some hurdles to clear for consumers. Eye appeal is important to consumers when purchasing beef. Most are looking for a bright red color. Irradiation can turn beef a more brownish or grayish color, according to Iowa State University researcher Dong Uk Ahn.

Another problem has been odor. Ahn has found that adding certain natural products to beef before irradiating it allows the meat to maintain a healthy, red appearance and inhibits odors that can result from the process.

By adding an antioxidant and vitamin E, which are both natural compounds found in living organisms, to the beef, Ahn was able to prevent color change and odor-causing lipid oxidation.

"The color change and odor that comes from irradiating meat is due to the oxidation of lipids and pigments, and small changes in proteins in meat," said Ahn. "This process slows down oxidation and removes the unfamiliar odor from irradiated meat."

He said his research likely will most benefit ground beef since the additive can be mixed into the meat during the grinding process, before they are pressed into patties.

Ahn stressed the importance of irradiating meat and other food products for consumer safety.

"The irradiation process benefits those who need it most, people who may be susceptible to illness brought on by bacteria--especially children and the elderly," he said. "The nutritional value of the meat is not affected."

Currently, Ahn's research cannot be used on meat available to consumers. Irradiation is considered an additive by the FDA. Meat cannot have more than one additive by regulation.

"I hope the FDA will change irradiation's classification from an additive to a treatment, or approve the use of irradiation in processed meat, a petition that has been pending since 1999," he said.

Once the approval is accepted or changed, Ahn said many people will be interested in his technology.

Use in other foods

After the spinach and lettuce illness outbreaks in 2006, more emphasis was put on prevention. In August 2008, the FDA approved irradiation pasteurization to be used on fresh spinach and iceberg lettuce to kill illness-causing bacteria.

"If the FDA had approved irradiation sooner and it had become a more common practice, we could prevent illnesses and deaths," said Olson.

"What's sad is that the FDA, after a nearly nine-year review, selected only two products involved with the massive illnesses in 2006," he added. The FDA is still considering what other types of produce might be safely irradiated, including other leafy vegetables, tomatoes and peppers.

What is significant about the newest FDA rule is that it is the first time the federal government has allowed produce to be irradiated at levels sufficient to kill E. coli, salmonella and listeria--all microorganisms that make people sick.

The FDA has approved the use of irradiation to eliminate insects from wheat, potatoes, flour, spices, tea, fruits and vegetables since 1985, but it couldn't be used to treat vegetative pathogens until now.

Consumer acceptance

Olson stresses the importance of using irradiation to prevent foodborne illnesses.

"Cost and consumer acceptance are the two biggest obstacles that still stand in the way of irradiation," he said.

Irradiated ground beef generally costs 20 to 30 cents more per pound than non-irradiated.

Olson said there is a challenge to meet the demand for the irradiated product since there is a limited number of commercial irradiation facilities in the country.

A facility was recently opened in Sioux City, Iowa. Other facilities are at Texas A&M University and another in Mulberry, Fla. These are the only three that have Food Safety and Inspection Service license and registration to irradiate food and feed products.

Several companies currently irradiate spices on-site in much smaller facilities.

Olson said for companies to be able to afford to add irradiation to their process, they would need to add an on-site facility.

"In just the ground beef market, with 8 billion pounds of ground beef being sold each year and facilities like the one in Sioux City running at a 200 million pounds per year capacity, we would need 40 facilities," he said. "That is why it would be more economical to add it to current facilities in order to reduce transportation and labeling expense."

The Schwan Food Company and Omaha Steaks currently irradiate 100 percent of their ground beef. Some other smaller companies also market irradiated beef on a smaller scale.

The use of irradiation destroys pathogens that lead to foodborne infections. The Centers for Disease Control estimates that 76 million Americans get sick, more than 300,000 are hospitalized, and 5,000 people die from foodborne illnesses each year.

"It's unfortunate that people have to get sick for us to get requirements to prevent the illnesses," said Olson.

Date: 11/7/08



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