Page 39 - FoodFocusThailand No.164 November 2019

STRONG QC & QA

Evolution of

Molecular Methods

and Their Application

in Food Diagnostics

Mr.Scott Egan
Pathogen Technical Specialist The most common application for molecular diagnostic technology
3M Thailand in the food industry is for pathogen testing, however applications also
scott.egan@mmm.com
exist for identification of spoilage organisms and food authentication
eg. identification of fish species.
Molecular methods are currently well suited and accepted for
meeting regulatory requirements such as screening of end products for
pathogens. Given the speed and accuracy of molecular methods they
are also routinely used as part of the internationally accepted best
practice to screen samples from the manufacturing environment to
identify potential sources of contamination.
Adoption of newer molecular technologies such as next generation
Over 150 years ago, in 1860’s, Swiss chemist sequencing/whole genome sequencing (WGS) is also becoming more
Friedrich Miescher observed and described a chemical common, although the use of this technology is mostly confined to
compound he isolated from white blood cells with government or research organizations for use in outbreak investigations.
This technology requires the organism to be isolated from the sample
unusual properties. He called the substance nucleic, in pure form, so along with the cost and complexity, this technology
which we know today as deoxyribonucleic acid, or more currently has limited potential for routine sample testing.
simply and commonly, DNA. A newer technology which is emerging from WGS is metagenomic
sequencing which allows a complex (mixed) sample to be analyzed.
It then took almost 100 years for the now famous double helix This technology sequences the full range of genetic material present
structure of DNA to be discovered by Nobel prize winning pair Watson in the sample and through specialized software and a large amount of
& Crick in 1953, but since that time, new discoveries and the introduction computing power it can provide the identification of all organisms’
of related technologies has been rapidly accelerating. During the 1970’s present. This technology would not only be able to identify pathogens
with DNA technology in its infancy the first DNA sequences were present in the sample, but future research may also provide insights
unlocked, and the first genetically modified organisms were produced.
This was followed by the invention of the Polymerase Chain Reaction
(PCR) in the 1983 by Kary Mullis, finally allowing scientists to start
harnessing the power and unlocking the secrets of DNA faster than
ever before.
The use of DNA technology has changed the world from enabling
medical diagnosis and treatment, assisting criminal investigations to
improving the output of the agriculture sector. With the more recent
discovery of CRISPR and emergence of next generation/whole genome
sequencing the future of DNA technologies is likely to continue
accelerating.
DNA technology has also dramatically impacted the food industry into how pathogens interact with other flora present in a sample and
beyond the introduction of genetically modified crops, in particular with likelihood to cause disease, making it an exciting prospect for the future.
the introduction and ongoing development of molecular diagnostic So, while we are continuing to see these advances in molecular
technologies. The first commercially available PCR based molecular technology being applied to food diagnostics, for the foreseeable future
method for the food diagnostic industry was released in 1992. In the these newer technologies will be limited to government or research
following years newer technologies such as real-time PCR and organizations.
multiplexing became available and most recently a new generation of Routine testing of food for pathogens is currently well served using
amplification technology using Loop Mediated Isothermal Amplification available molecular methods and when selecting a method, the focus
(LAMP) has been commercialized. Each new generation of technology of users should be on ease of use, reliability, accuracy, time to result,
will typically come with enhancements in time to result, accuracy and throughput and of course support from the equipment/kit supplier.
ease of use.

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