A Better Way To
Kill E. coli?
Source of Article: http://www.miller-mccune.com/article/a-better-way-to-kill-e-coli-1046 As food irradiation remains
a sensitive subject in the U.S., the mechanics of killing bacteria on food
without irradiating it just got a little easier. Kevin
Keener’s in-bag ozonation method creates ozone in packaged foods by using
high-voltage coils to charge the gas inside sealed food packages, effectively
killing any bacteria inside them. In this demonstration with a bag of
tomatoes, helium has beenTom Campbell/Purdue Agricultural Communication The
March 2008 issue of Miller-McCune
magazine examined the debate surrounding the U.S. Department of Agriculture’s
rules for leafy green safety certification; in particular, the article highlighted proposed changes in industry
practice in the wake of the 2006 E. coli outbreak in spinach, which killed
three people and sickened more than 200 across the United States and Canada. According to the Centers
for Disease Control and Prevention, about 40,000 cases of salmonellosis, an
infection caused by salmonella, occur each year in the United States causing
400 deaths. In addition, about 70,000 E. coli infections are reported each
year, killing dozens. How to kill the bacteria?
Irradiation has been a widespread but costly practice in Europe, and studies
in the U.S. have shown that irradiation of leafy green vegetables eliminates
most bacterial contamination, leaving the treated greens largely
indistinguishable from untreated produce. Although food irradiation is
allowed in nearly 40 countries and is endorsed by the World Health
Organization, for the American Medical Association and many other
organizations, it remains a controversial option. A Purdue University
researcher has discovered a simpler way to eliminate bacteria in packaged
foods like spinach. By placing two high-voltage, low-watt coils on the
outside of a sealed food package, a plasma field is formed in which oxygen is
ionized and converted into ozone, which then kills bacteria such as E. coli
and salmonella. The process is outlined in an article in LWT — Food
Science and Technology, a journal for the Swiss Society of
Food Science and Technology and the International Union of Food Science and
Technology. “Conceptually, we can put
any kind of packaged food we want in there,” said Kevin Keener, an associate
professor in Purdue’s department of food science, in a release announcing his
discovery. “So far, it has worked on spinach and tomatoes, but it could work
on any type of produce or other food.” The process uses only 30 to
40 watts of electricity, making it less of a power drain than most
incandescent light bulbs. Because the container’s exterior only increases a
few degrees in temperature, the food inside is not cooked or otherwise
altered during the treatment, which can range from 30 seconds to five
minutes. The longer the gas in the package remains ionized, the more bacteria
are killed before the ionized gas eventually reverts to its original
composition. “It’s kind of like charging
a battery. We’re charging that sample,” Keener said. “We’re doing it without
electrode intrusion. We’re not sticking a probe in the package. We can do
this in a sealed package.” Glass containers, flexible
food-storage bags and rigid plastics, such as strawberry cartons and pill
bottles, have all stood up to testing. A patent on the technology is pending,
and Keener said the next step is to create a commercial prototype of the
device for large amounts of food. |
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