U.S. Water News Online
MANHATTAN, Kan. -- While industry professionals continue
talks with government officials on using irradiation to kill anthrax
spores in U.S. mail, a Kansas State University food scientist says
that research indicates the technology can be an effective way of
killing the deadly bacteria.
Randy Phebus, a food safety microbiologist with K-State Research
and Extension, said that some U.S. mail already is being irradiated.
Researchers liken the process to the well-established process of
using irradiation to sterilize medical devices.
"I'm confident that using gamma irradiation at the levels that are
routinely used to sterilize medical supplies would be effective in
killing the anthrax spores," Phebus said.
On its website last week, the U.S. Postal Service announced that
it is "adopting and immediately deploying" irradiation to fight the
current anthrax threat. Two Washington D.C. postal workers died last
week due to inhalation anthrax.
Killing anthrax spores with irradiation will require a level that
is at least 10 times higher than the amount of radiation needed to
protect food from harmful bacteria, according to researchers at Iowa
State University. The level of irradiation used for poultry, red
meat, spices, fruits and vegetables is 3 kiloGray (kGy) or less.
Jim Dickson, an associate professor and chair of the Department of
Microbiology at Iowa State, said killing anthrax spores will require
a 30 kGy level of irradiation. He noted the recommendation for
killing anthrax -- scientifically known as Bacillus anthracis
-- is partly based on testing irradiation against a comparable
organism, Bacillus cereus.
"There's not a lot [of research] out there specific to anthrax,"
But noting that irradiation is "not an unfamiliar technology,"
Dickson said that its current use for sterilizing medical items also
gives a good indication that it will be successful in sterilizing
mail. Medical supplies typically are irradiated with 25 kGy.
As with its other uses, irradiation would not make mail
radioactive, Dickson said. It's also considered safe for people
working around the irradiation systems, if they stay within the
guidelines for using the technology.
Phebus and Dickson both discounted recent reports that mail could
be sterilized by using a steam iron. Dickson said people would have
to keep the iron directly on the mail for approximately 30 minutes,
which may kill anthrax spores, but may also cause a fire.
U.S. companies with irradiation units were in discussions with
government and postal officials last week. A spokesperson for one
company -- the Steris Corporation in Mentor, Ohio, which has 16
facilities in North America to sterilize medical equipment -- said
the companies "definitely have the technologies available."
A statement from the U.S. Postal Service notes that "this new
technology will not be cheap, but we are committed to spending what
it takes to make the mail safe." Early indications, said the Steris
spokesperson, is that units to irradiate mail will have to be built
on-site. Iowa State's Dickson said he knows of only one portable unit
available in the country, built by Gray*Star Inc. of Mt. Arlington,
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