It’s often said that the future is now, which may explain why so many people are unprepared for it.
Explore this issueFebruary/March 2011
The phrase is meant to reflect the immediacy of modern life, but it can be taken to explain why the attributes of the present seem so often unmanageable. Take the globalization of the food supply: It’s here. It’s off and running. And now we have to catch up with it.
For starters, as pointed out by Paul Zavitsanos, product marketing manager for Agilent Technologies in Santa Clara, Calif., food-related microbiology has a lot of catching up to do.
“When I entered this field 35 years ago,” Zavitsanos said, “a large portion of work in chemical labs involved glassware and boiling solutions and condensing vapor … making colors. But now, you dissolve the stuff and shoot it into an instrument.” This is not the case in microbiology. “Today we still test largely the way Pasteur used to”: isolate, enrich, and, in some low-tech way, identify—often using a confirmatory metabolic test. Which is not to say the right tools aren’t out there; in the immediate future, Zavitsanos wants to bring the already available and near-term novel instrumentations to microbiology.
To that end, Agilent recently entered into a collaboration with the University of California at Davis to develop a new process of pathogen identification that, from field to finding, takes a matter of hours rather than days. The technology, called MassCode PCR, will use mass-tagged PCR primers to amplify target genes-of-interest, liquid chromatography (LC) to resolve the target, and mass spectrometry (MS) to identify the bug in question, with the current project to focus on Salmonella spp. The technology will combine the sensitivity of the LC/MS with the reliability of the dual barcode approach to polymerase chain reaction (PCR) that eliminates false positives.
Zavitsanos is certain this technology will shorten the duration of, if not prevent, outbreaks of certain foodborne diseases. “With traditional technologies, it takes two weeks to get the first round identification of a bug, and then verifications must be performed.” With MassCode quickly nabbing the suspect, exposure time for the general population might be cut in half.
“It’s tough to make predictions, especially about the future.”
As with all things new, this bug-finding strategy may have its own bugs. Zavitsanos is uncertain, for example, of the effect MassCode’s potential sensitivity will have on the enrichment phase—the step prior to loading a PCR. “It might be sensitive enough and selective enough where certain enrichment technologies are no longer required. We just don’t know.”
Should enrichment remain an issue, as is likely, PhD candidate Brian Poe, of the University of Virginia at Charlottesville, may have a suggestion. Poe just presented his data regarding an acoustic cell trapping method that rapidly concentrates a pathogenic sampling at Pittcon, the laboratory science conference.
“We used ultrasound to create low-pressure zones within a microfluidic device,” explained Poe, “and in those zones any particles, or cells, are localized into that site.” The idea is to improve the time and circumstances involved in current sample preparation in the monitoring of wash water used in food production. Currently, the time is long, and the place is a bulky centrifuge.
In his investigation, Poe tethered the acoustic trap to another innovation, an ultra-rapid, infrared-mediated microchip PCR now being commercialized by Poe’s adviser, James Landers, PhD, chief scientific officer of the biotech company ZyGEM. “We integrated the two steps: Flow the sample through the cell-concentrating trap, then perform heat lysis and sequence amplification—all within the same device.” The process is rapid and the device portable.