Jan 29, 2010 (CIDRAP News) – When people think of food irradiation, they probably think about irradiation of ground beef to kill E coli. So when a company whose pepper-coated salami has been linked to a 40-state Salmonella outbreak pledged this week to use irradiated pepper from now on, it may have raised some eyebrows and sparked new interest.
Daniele Inc., a Rhode Island firm, reported this week that it found Salmonella in black pepper it uses to coat some of its salami products. Yesterday Rhode Island's health department said it found the outbreak strain in an open container of pepper from Daniele. The department was still awaiting results of tests on unopened containers.
Spices have been irradiated for safety in the United States for years, but the process has largely been invisible. That's because it has been limited to spices used as ingredients in other foods—mostly ready-to-eat foods, according to food industry officials. Under Food and Drug Administration (FDA) rules, such foods don't have to be labeled as containing irradiated ingredients.
Grocery shoppers won't find any irradiated packaged spices on store shelves, because those products have to be labeled as irradiated, and food companies fear that will scare consumers away, industry sources say.
"There are no retail spices that are irradiated, primarily due to the fact that they have to be labeled," said Steve Markus, director of food safety and commercial products for Sterigenics, a company based in Oak Brook, Ill., that sterilizes food and medical supplies with irradiation and other methods.
McCormick & Co., a major marketer of retail spices, does not use irradiation on any of its consumer products, relying instead on steam sterilization and other methods, said company spokeswoman Laurie Harrsen.
"While irradiation of food products is both effective and lawful, our McCormick US Consumer Products Division does not irradiate any of its consumer products at present (and has no plans to do so in the future) as we believe there is insufficient consumer acceptance of irradiation to date," Harrsen told CIDRAP News by e-mail.
Spices that McCormick produces for industrial food customers are also treated by steam sterilization and other processes, she said, adding, "We will only send product out for irradiation if specifically directed to do so by that industrial food customer (it is not a common request)."
However, irradiation of spices is far from rare, according to other industry sources. Estimates vary but suggest that up to a third of the overall volume of spices marketed in the United States is irradiated.
On the basis of numbers from four providers of irradiation services, Ronald Eustice, executive director of the Minnesota Beef Commission in Minneapolis, estimated that about 175 million pounds of spices are irradiated annually, or about a third of commercial production. Eustice is a proponent of food irradiation, especially for meat.
Markus, of Sterigenics, said the FDA has estimated the amount of irradiated spices at about 190 million pounds annually. (The FDA was asked for an estimate but did not provide one in time for this article.)
Jim Prevor, an expert on the perishable-food industry, the editor of two food industry magazines, and writer of the "Perishable Pundit" blog, estimates that the share of commercial spices undergoing irradiation is probably only about 15%.
"The real number we don't have a specific handle on," Prevor said. "For spices used in ready-to-eat foods I'd say the number is slightly higher. My guess would be 25%."
"The significant thing is really not the total percent, it's the percentage of spices used in ready-to-eat foods, and there's even less information on that than on the total amount," he said.
Irradiation is often used with spices that are added to ready-to-eat foods after they have been cooked, since those foods are not cooked at home.
"The spices that are being treated [with irradiation] are those that don't go on to applications where it's further processed," said Markus. "The bacteria is killed at that point."
Prevor speculated that the salami-related Salmonella outbreak may spur greater interest in irradiation of spices. "I think this is sort of a wake-up call for the industry," he said.
But given the limited irradiation capacity in the United States and the large share of it that is dedicated to sterilizing medical equipment, Prevor expressed doubt about the ability to quickly expand irradiation of spices.
Other than irradiation, methods that are commonly used to kill microbes in spices—nearly all of which are imported from tropical countries—include steam sterilization and fumigation with gases such as ethylene oxide and propylene oxide, according to industry sources.
Food irradiation for safety involves exposing the target food to ionizing radiation, which can come in the form of an electron beam, gamma rays from a radioactive substance such as cobalt-60, or x-rays. The process kills microbes by disrupting their DNA. It does not make foods radioactive.
Food irradiation for safety is permitted in more than 40 countries and has long been endorsed by major medical and health organizations, including the World Health Organization. The FDA says it has evaluated irradiation safety for more than 40 years and found it safe and effective for many foods. When performed properly on suitable products, irradiation does not impair nutritional quality or change the taste or texture of food, according to the agency.
Markus said Sterigenics, which he described as the leading US irradiation provider for spices, uses cobalt-60 to treat spices, because it is more effective than the other irradiation technologies. Gamma rays penetrate food much better than the other forms of irradiation, he said.
He also said irradiation works much better than a fumigant like ethylene oxide on items like spices. "The effectiveness of ethylene oxide is not nearly as good as irradiation," he said. "It may provide a 1- to 2-log reduction [in microbial load], whereas with irradiation you can create near-sterility."
FDA overview of food irradiation