The topic of food irradiation is one that stirs up controversy almost as easily as the use of instant replay for a sporting event or any discussion on the national debt. On some fundamental level, everyone can understand and agree that we must do something to control foodborne pathogens, but no one can agree on what that something is.
The positions of the pro-food irradiation camp and the anti-food irradiation camp are fairly well defined. The pro camp says that they can eliminate 99-99.9% of the pathogens on product as well as kill pests that might be in the product. This can be accomplished without the application of chemicals that might leave behind residue, resulting in a safer product with a significantly extended shelf life. Any loss of nutrients or change in taste due to the radiation is comparable to other sterilization processes. We are all comfortable with the pasteurization of milk, and that has a significant effect on taste. But we have come to accept its use in the name of food safety.
The anti camp believes irradiation will not kill all of the pathogens, and thus, we are creating a false sense of security for the consumer. These people are also concerned that irradiation affects the taste, smell and color of the product. In addition, they claim that there have not been enough studies to determine the long-term effect of the byproducts produced in food by irradiation, called radiolytic products.
In addition to these points, food-processing companies are concerned about consumer acceptance of irradiated products. There are some consumers who fear that any irradiated food will contain trace amounts of radiation, even though this has been shown to be completely without merit. These consumers are also concerned about changes in the taste, smell and color of the product.
Given these relatively firmly entrenched positions, you might think that nothing is happening in this area. That is not quite true. The cost of a product recall and its effect on the financial health of a company has served as a motivation for some food processors to consider irradiation.
In the protein market, for example, one frequent source of product recall has been ground beef. This is due to the unique difficulties in killing pathogens in the product. In response, Omaha Steaks has been irradiating their ground beef since 2001 with overwhelming consumer acceptance. In fact, the company says many consumers will only buy their ground beef because they believe Omaha Steaks provides a safer product. Likewise, test-marketing of specific irradiated foods has shown that when consumers are educated about irradiation, approximately 80 percent will buy irradiated products.
Other food processors are also considering the use of irradiation to prevent product recalls and to meet government food-safety regulations. For the fresh fruit and vegetable industry, the control of pathogens and pests is particularly difficult because many of these products are eaten in their raw state. The recent incidents involving E. coli-contaminated lettuce and spinach have prompted the government to approve irradiation of these products.
Irradiation is also thought to be effective for pest control. Many fruits coming from outside of the U.S. must be fumigated to kill pests that might be on or inside the fruit. Ethyl bromide has been the chemical of choice for this application, but due to health concerns, its use is being phased out.
Houston-based ScanTech Sciences has developed an electronic cold pasteurization technique for produce that generates intense beams of high-energy electrons. One of its advantages is that, unlike irradiation, it does not rely on radioactive material to generate gamma rays to kill pathogens and pests.
While in operation, the ScanTech system generates powerful electron beams that can penetrate about 2.5 inches into food from the direction of the source (typically, two sources would be used, one from the top and one from the bottom). However, when you turn off the system, there is no radiation and no radioactive source that must be shielded from workers. ScanTech is currently working with Texas A&M and the state of Texas to build an irradiation facility near the border with Mexico to use the system in a food-processing environment.
Commercial food irradiation technology has existed for many years; however, only a small number of the products we consume have been approved for irradiation. This is due to the fact that the natural variability found in most food products complicates the determination of the optimal energy levels needed to irradiate a specific product. Research universities are working with the FDA to conduct product-specific energy optimization studies with the goal of expanding the approved use of irradiation for more food products.
While the jury is still out on the use of irradiation as a food-safety tool, one thing is clear â€” the control of foodborne pathogens using safe and affordable technologies is everyone’s goal. With continued advances in irradiation technology and an increasingly educated public, its use may become more acceptable over time.
McMurray oversees research in sensing, robotics, energy and environmental areas at Georgia Tech Research Institute. He has 20 years experience.
Irradiation debate continues
September 1, 2010