An Exclusive Interview with Dr. Patrick Mester, group leader at the Christian-Doppler Laboratory for Monitoring Microbiological Contaminants
Franzisca Gartenmann, Marketing Manager at NEMIS Technologies:
As part of my work at the Christian Doppler Institute, we conducted a project for a large Austrian company where we replaced the complete diagnostics from their existing immunoassay solution to a new PCR system. This saved valuable time and reduced 60% of their initial costs, amounting to approximately one million euros. This switch demanded a high intensity training and an extensive support phase. In the meantime, more than 100,000 samples have been analyzed and a lot of expertise in this new system has been gained. The PCR method is very sensitive but also very expensive, having always been a significant disadvantage, until now. In this project, we analyzed the company data of the last few years in detail, and it quickly became apparent that a large part of the samples was negative. You must imagine that they examine about 20,000-30,000 samples per year. Of these samples, 95% to 99% are pathogenic listeria free.
Accordingly, we developed a system in which ten samples are combined, i.e., pooled, which makes it possible to exclude most samples after one day. However, if you have a positive result, you lose a bit of time compared to the original concept. In that case, the ten pooled sample sites have to be tested again individually to find out where the contamination is. Positive samples are sent to an external laboratory to obtain the isolate. It is crucial to understand whether the same house germ has repeatedly been appearing for years and could not yet be removed from the production environment or whether a new strain has been introduced. But if 99% of the samples are negative, you can save a lot of time and money. With the old system, it took at least two days to get a negative result. With the new system, we are now at one day. Through pooling, we have reduced costs enormously even with the follow-up examinations, which are more expensive per se. PCR is still heavily criticized for the associated costs because the individual reactions are still expensive. Typically, a single test costs 8-10 euros, which only includes the material costs and not the laboratory. With pooling, however, you decrease this value because you test ten sample sites simultaneously.
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We have a lot of experience in the food industry and are researching methods that allow us to quickly concentrate bacteria from food, i.e., to isolate them. The objective is to concentrate bacteria from a dairy product such as milk and reduce thereby the overall enrichment volume needed. We did experiments with AquaSparkTM and were pleased to find a very low single CFU detection limit with this method. This motivates us to analyze this approach further. We are planning to publish the results once the study has been completed.
They can be complementary as well as competitive. PCR only works if a company has its own laboratory, i.e., the method is only worthwhile for a certain company size. This applies to only a fraction of companies. Small or even medium-sized companies cannot afford it. In such cases, there is no competitive situation. In my opinion, this is the significant advantage of your method because the tests can be performed on-site without existing laboratory infrastructure.
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