Which rapid microbiological test methods are preferred by
food processors, and what attributes of rapid tests are most
important to them?

There has been substantial growth in the development and use of rapid methods since their
introduction to the market over the past 25 years or so. When these methods were first
introduced, they were originally intended for use by food processors in their in-house
laboratories. Over the past decade, however, fewer and fewer food companies have
continued to maintain an in-house microbiology lab, mainly due to the concern for cross-contamination when working with pathogen samples.

Tests such as polymerase chain reaction (PCR), lateral flow immunoassay, enzyme-linked
immunoassay (ELISA), automated bioburden testing, and similar instrument-based methods
are becoming more common in food safety.

PCR and instrument-based ELISA are two of the most commonly used test formats in food
processing facilities, and primarily for pathogen analysis. These tests are commonly employed
as part of a company’s environmental monitoring program and to guide their sanitation and
cleaning programs as part of their product changeovers on production lines. Companies also
implement the use of rapid indicator swabs—protein swabs, rapid bacteria growth indicator
swabs, and similar tests for cleaning verification and in order to speed up the product
changeover processes. Some companies use rapid bioburden tests—which characterize the
presence of microorganisms using ATP, monitoring of CO2, enzymatic colour change, and
other indicators of microbial growth—primarily for product release testing.

A high volume of companies use rapid indicator ATP swab tests. These tests have, over the
past 20 years, become a commonplace for use in cleaning verification in food and beverage
plants. The proportion of plants using ATP swabs and the intensity of testing varies widely in
other world regions depending the country, the product being produced, the level of exports,
and other factors.

Aside from the question of which tests are being used, the question of why rapid
microbiological methods are being used is of equal or greater importance. Again, not
unexpectedly, the main reason that processors choose rapid methods is that they produce
“faster results”.

This reason, however, has evolved over the past 20 years or so since rapid microbiological
methods have become more common. Early in their adoption, rapid microbiological methods
were employed at in-plant microbiology labs to produce faster results for product release
testing, especially faster results for the presence of pathogens. Since decisions to ship product
were held pending lab results, faster results meant faster and more efficient logistics and less
need for finished product inventory and storage.

However, with a large volume of pathogen tests now being outsourced to commercial labs,
food companies who use rapid microbiological methods are less solely driven by the “need
for speed” for product release, as the analytical turnaround time for these tests is now the
responsibility of their commercial lab partners.

Rapid microbiological methods are now more commonly used for internal operational
decisions. Most companies might reason that their need for faster results from the use of
rapid microbiological methods in-plant is mainly driven by product changeovers and decisions
regarding their environmental or sanitation program. Faster results may indeed allow for
faster decision-making, especially decisions based on real-time results.

This means that the test not only needs to be fast, but also easy to use, because these tests
will be used in-house, often by individuals who are not lab analysts and who may have little
or no microbiological testing experience. Speed and results turnaround time (TAT) and ease
of use may very well be number one and number two in importance for the use of rapid
microbiological methods for a food processor plant.

While it is understood that many of the tests may not be as accurate, or have the selectivity,
specificity, level of detection or other, similar analytical characteristics as laboratory-based
reference methods, they nonetheless need to be accurate and reliable, at least to a level that
makes them useful in the application in which they will be employed. This validation typically
comes from third-party validation organizations (e.g., AOAC, AFNOR, MicroVal, NordVal, etc.)
and can be considered as a “must have” for most of these tests.

KLM HIGH-giene SOLUTIONS supplies a wide range of rapid indicator swab test kits to the
food and beverage industry.

You can contact us for more information and/or quotation.