Rapid Pathogen Detection
Method Helps Lab Meet
Customer Needs
Whether conducting testing in-house or choosing to contract with an independent reference lab, food processors’ decisions regarding pathogen detection technology and methods play a
critical role in their overall food safety program. As a respected microbiol-
ogy reference lab, TRAC Microbiology of Madison, WI strives to provide
customers with the fastest and most accurate pathogen testing results
possible. Recently, the lab was faced with a need to upgrade its pathogen
detection technology for Salmonella, Listeria, E. coli
O157:H7 and Enterobacter sakazakii.
“As market pressures continue to increase, our
customers look to us to help them meet their food
safety objectives—quickly, with a high degree of
sensitivity and with AOAC-approved methods. In the
area of pathogen detection, classic cultural methods
and even many of the rapid methods no longer meet
our customers’ needs,” says Virginia Deibel, TRAC
Microbiology CEO. “However, advancements in ge-
netic detection technologies have enabled TRAC to
provide the highly accurate next-day results our cus-
tomers require to remain competitive.” After con-
ducting extensive research and comparing multiple pathogen detection
technologies, TRAC decided to invest in the Assurance GDS™ pathogen
detection system from BioControl Systems, Inc., a Bellevue, WA-based
leader in food safety testing.
www.biocontrolsys.com
Market Demands Accuracy and Next-day Results
When Matt Howard, genetic scientist at TRAC Microbiology, began
looking to improve the lab’s pathogen detection program, he knew where
to start. “I needed a system that we could be confident would give us accurate results for a full array of pathogens across a wide variety of sample
matrices,” explains Howard. “When you combine that with the market demand for next-day test results, it immediately narrowed the field to PCR-based systems.” Because PCR directly targets and amplifies a specific
DNA sequence of an organism, it is widely accepted as the most specific
and sensitive detection technology currently available.
Due to the critical nature of pathogen testing in food samples, accuracy
was at the top of TRAC’s list of performance criteria for TRAC. Thanks to
Howard’s background in genetics and past experiences with PCR, he was
able to further narrow the list of candidates. “We definitely needed a system that combined the specificity of both primers and probes. Because
probes provide sequence-specific detection of the amplified DNA and
melting-curve systems rely on non-specific dyes such as SYBR Green, I
knew we could have greater confidence in results from a probe-based
assay,” he states. “Additionally, results from a probe-based system don’t
require the subjective interpretation often necessary to determine the results of melting curves.”
Performance Factors Essential in Method Selection
However, there were many other factors that had to be considered before making a final decision, including AOAC approvals, ease of use, relia-
bility and of course, cost. While some systems were able to satisfy one or two of
these requirements, Assurance GDS
proved to be the only system that could
satisfy all of TRAC Microbiology’s stringent performance criteria.
The system takes advantage of advances in sample preparation techniques
and molecular biology to provide a high
degree of accuracy. The system provides
three levels of specificity, which include
immunomagnetic separation (IMS) during
sample preparation to concentrate the
sample and remove PCR inhibitors, highly
specific primers and patented DNA
probes, which ensure accurate detection
of the target organism. Combined, these
features provide the accuracy that TRAC
personnel were looking for.
The single-step enrichments and simple sample-prep procedures of the Assurance GDS system produce a streamlined
workflow that was easily implemented in
TRAC’s lab. The shortened enrichment
times and the innovative multi-channel rotary cycler combined to yield results faster
than other PCR methods.
Implementing this system in the lab
has proven very beneficial to TRAC Microbiology as well as its clients. “The advanced technology and inherent accuracy
of Assurance GDS complements TRAC’s
position and reputation as an innovative
leader in testing, research, auditing and
consulting,” says Howard. “We have, of
course, been able to improve our service
to existing clients and gain new clients
based on our ability to confidently provide
faster results.”
The ease and efficiency of the assay
protocols has enabled TRAC Microbiology
to substantially reduce the amount of
hands-on labor and time required for
pathogen testing, helping to greatly improve the company’s lab operations. The
ability to obtain next-day results for both
food and environmental samples offers
tremendous value to food processors as
well. These faster pathogen test results
allow organizations to confidently release
product sooner, maximizing shelf-life and
reducing inventory holding costs. Additionally, faster results for environmental
samples allow processors to identify and
address potential problem areas in the
plant sooner, reducing the quantity of
product potentially exposed to a possible
source of contamination.
