Good Vibes for Bad Bugs
When the device is turned on, the cantilevers begin vibrating rapidly, generating a baseline
electrical signal. But when an E. coli cell, for example, binds to one of the antibodies, the frequency at which the cantilever vibrates changes, producing a change in the electrical signal.
And how will this device be used? Dr. Mutharasan explains that the first uses would be
in a food processing facility, but that he can imagine that one form of the technology might
even make it into our homes some day.
“I envision two or three versions of the applications of this method. One that is currently
being developed in which you have a little test tube that contains your sample and you
insert the sensor, somewhat like a thermometer, and you have a little electronic device
that interfaces, perhaps something like a smart phone, and in a matter of a short time
period, maybe 15 minutes, you’ll get information that is adequate enough for you to
take corrective action. That’s one version of this application, and we’ve done enough
tests to be confident that format will work.”
Food Hot Spots
Even the best sensing technology has a major limitation: the quality of the samples used in the analysis.
Workers usually obtain those samples by taking random swabs of food during processing. The approach
may miss “hot spots,” isolated areas of contamination
that later may spread throughout the batch. Food scientists address this problem by taking a large number
of swabs that will hopefully pick up any contamination
that’s present on a particular food.
Dr. Jacob Petrich, a chemist at Iowa State University,
is taking a different approach. As described in the ACS’s
Journal of Agriculture and Food Chemistry, this method
enables meat packers to scan an entire animal carcass
at once for the presence of spinal and brain tissue,
which can harbor infectious proteins known as prions.
Those agents cause bovine spongiform encephalopathy — mad cow disease — and its human counterpart,
the incurable brain condition called Creutzfeldt–Jakob
disease. Here is Dr. Petrich:
“This all stems from research we began in 1997 to see if there was E. coli contamination
on these products. Instead of deciding to look for single E. coli 0157 bugs on a carcass,
we decided to look for the agent that puts it there in the first place, which is feces. And
we discovered that feces fluoresces intensely when irradiated and that’s enabled us to
develop devices that are actually in packing plants now. In the course of testing that
device, we were in the course of irradiating a carcass with light and we realized that
spinal cord fluoresced.”
It fluoresced with a soft glow that could help safeguard meat from the agent responsible
for a fatal brain disease. That’s really shining a light on our subject of providing safe food.
Thousands of other scientists are doing the same, with discoveries that respond to challenges
old and new of taking worry off the menu — on special occasions like Thanksgiving and
every day of the year.
Conclusion
Smart chemists. Innovative thinking. That’s the key to solving global challenges of the 21st
century. Please join us at ACS for the next chapter in this ongoing saga of chemistry for life.
In our next special Global Challenges podcast, we’ll examine how chemists are helping to
make our food more nutritious.
