zone machine keeps
bacteria at bay
machine keeps bacteria at bay
Source of Article: http://www.rdmag.com/ShowPR.aspx?PUBCODE=014&ACCT=1400000101&ISSUE=0903&RELTYPE=PSC&PRODCODE=00000000&PRODLETT=S&CommonCount=0
A Purdue University researcher has found a way to eliminate bacteria in
packaged foods such as spinach and tomatoes, a process that could eliminate
worries concerning some food-borne illnesses.
Kevin Keener designed a device consisting of a set of high-voltage coils
attached to a small transformer that generates a room-temperature plasma
field inside a package, ionizing the gases inside. The process kills harmful
bacteria such as E. coli and salmonella, which have caused major public health
Keener's process is outlined in an article released online early in LWTFood
Science and Technology, a journal for the Swiss Society of Food 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 Keener, an associate professor in the Department of Food
Science. "So far, it has worked on spinach and tomatoes, but it could
work on any type of produce or other food."
By placing two high-voltage, low-watt coils on the
outside of a sealed food package, a plasma field is formed. In the plasma
field, which is a charged cloud of gas, oxygen has been ionized and turned
into ozone. Treatment times range from 30 seconds to about five minutes,
Ozone kills bacteria such as E. coli and salmonella. The longer the gas in
the package remains ionized, the more bacteria that
are killed. Eventually, the ionized gas will revert back to its original
The process uses only 30-40 W of electricity, less than most incandescent
light bulbs. The outside of the container only increases a few degrees in
temperature, so its contents are not cooked or otherwise altered.
Other methods of ozone treatment require adding devices to bags before
sealing them to create ozone or pumping ozone into a bag and then sealing it.
Keener's method creates the ozone in the already sealed package, eliminating
any opportunity for contaminants to enter while ozone is created.
"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."
Keener said testing has worked with glass containers, flexible plastic-like
food-storage bags and rigid plastics, such as strawberry cartons and pill
bottles. He said the technology also could work to ensure pharmaceuticals are
free from bacteria.
According to the Centers for Disease Control and Prevention, about 40,000
cases of Salmonellosis, an infection caused by
salmonella, are reported each year in the United States, causing 400
deaths. The CDC reports that about 70,000 E. coli infections are reported
each year, causing dozens of deaths.
Funding for Keener's research came from Purdue Agriculture. A patent on the
technology is pending.
Keener said the next step is to develop a commercial prototype of the device
that could work on large quantities of food.
story with photo and abstract
SOURCE: Purdue Univ.