Why today’s products are still being tested with yesterday’s microbiological technologies.
Walking through the supermarket offers access to a wide range of food and drinks. Colorful advertising promises maximum enjoyment at unbeatably low prices. But what about safety? The consumer simply assumes that the legislator has regulated everything necessary and that food is subject to sufficient quality control. But is that really the case?
Microbiology
In addition to various chemical and sensory analyses, food is nowadays tested for a variety of microorganisms and infectious agents. Care is taken to ensure that both pathogenic and product-spoiling germs are excluded. The aim of detecting bacteria is therefore to avoid endangering the consumer while at the same time protecting the product. There are a large number of pathogens that are regularly tested for in a wide variety of foods such as sausage, meat, dairy products and many more: Salmonella, listeria, staphylococci, clostridia and molds are just a small selection of these. Foods that are given to infants are particularly critical, as their immune system is not yet sufficiently developed to cope with hostile intruders. Cronobacter is particularly feared in powdered infant formula.
So much for the theory.
However, the current approach to quality control in microbiology has one major disadvantage: it often still uses outdated methods.
The “Gold Standard”
The “gold standard” for the detection method used is the cultivation method. Microorganisms are spread on an artificial culture medium or in an artificial culture medium.
Detection is positive when the bacteria start to grow on these culture media. However, this does not include germs that cannot grow on the artificial culture media. And there are far more of them than expected. It is now known that up to 99% of all bacteria cannot be detected using conventional methods, i.e. culture media. This figure may vary. The proportion of unculturable bacteria in environmental samples is higher (up to 99%) than in food samples. However, it always represents the majority.
Unculturable bacteria are not recorded
This means that only the germs that grow on the culture medium can be found in the food tests. For example, molds, staphylococci or salmonella. Unculturable bacteria are not detected during the test, but can possibly multiply in the food and contaminate it.
However, consumers expect a microbiological quality control system to detect all microorganisms relevant to them. However, this is not the case. However, this is only known to experts.
Molecular biological methods are more powerful
Molecular biological methods allow the detection of all bacteria, including those that cannot grow on artificial culture media. This is due to the fact that they do not focus on external characteristics (color, shape, etc.) or on the adapted ability to reproduce, but instead target genetic markers. There are now a number of powerful molecular biological methods such as VIT® gene probe technology, PCR and various nucleic acid tests that can and are used in routine analysis.
However, the legal regulations continue to focus on the “gold standard” of cultivation. It is therefore very difficult for modern processes to assert themselves in the industry against the tried and tested process, especially as they are usually more expensive for the company to implement. So why should the producer modernize the process if the legislator does not require it? Of course, modern detection methods are already being used in industry today. However, this is usually limited to “in-process” control in order to detect undesirable developments in production in good time and avoid faulty batches. The final inspection – the last test before it goes to the consumer – is usually carried out using conventional and legally approved methods.
Although innovative methods have been on the market for over two decades, they are still rarely used because there is simply a lack of pressure from legislators (who continue to rely on tried and tested methods) and consumers. However, very few consumers are familiar with the details so that they can form their own opinion and exert pressure.
THE CHANGE OF PERSPECTIVE
What if the “gold standard” was not cultivation but new molecular biological methods? Which can detect microorganisms regardless of their ability to grow on artificial culture media? Which simply detect all bacteria present in the food sample, for example? And suppose a new method called cultivation were to try to compete against this and be included in the regulations. Would it have a chance of displacing the “tried and tested” molecular biological methods? Even though it only covers a fraction of microorganisms? Hardly! Even if this method were cheaper, it would not be able to establish itself because it would detect fewer microorganisms in the products, ultimately making them less safe.
So if the “cultivation” method would have no chance against the more specific and comprehensive molecular biological methods in a “role reversal” and the only advantage would be reduced costs for the producer, why is it still the dominant detection method today?
What needs to change in the detection of bacteria?
Microbiological quality control will have to change in the coming years. The statutory regulations should finally be modernized and adapted to new methods. The focus must be clearly on the benefits for the consumer and the tried and tested must be abandoned.
The analysis of a microbiological sample must then no longer be determined by the technology used, but the aim must always be to obtain the entire microbiological picture.
The warehouse – a visual comparison
Imagine a large, unlit and therefore dark warehouse in which a package has been placed that needs to be found. A candle would only ever illuminate a very small area. Searching for the package placed in the warehouse would be an almost hopeless task with the dimly lit candle, as it could only illuminate a small spot at a time. However, if it were possible to suddenly light up the warehouse with a whole set of ceiling floodlights, the package would be found immediately.
The same applies to the detection methods: The method of cultivation is the candle. Innovative and molecular biological detection methods are the ceiling floodlights.
When Robert Koch’s cultivation method was established at the end of the 19th century, rooms were actually still lit with candles. The latter have given way to modern lighting technologies. However, microbiological detection methods have remained at the level of candles.
Now is the time to turn on the light! (JS)