Phages vs Bacteria – SWR Knowledge

Time and time again, food causes a serious bacterial infection. In 2011, more than 50 Germans died from EHEC, a type of coliform bacteria. Cultured viruses can significantly reduce the risk.

It is often the “ripe” foods that can become a fearsome gathering of bacteria. Raw milk cheese, for example, which potentially has the Listeria problem. Or smoked fish. In principle, they are preserved by smoking, but with longer storage they are still a haven for potentially life-threatening salmonella.
In the Netherlands, in the university town of Wageningen, there is the headquarters of a company that fights small monsters even with smaller monsters. Micro . company
produce bacteria. These are viruses that each specialize in a very specific strain of bacteria. Phages are produced in liquid bacterial cultures, where they multiply rapidly. Of course, it’s the exact bacteria that you’re supposed to be fighting later on on food. Phages are the natural enemies of bacteria. Micreos supplies phages against Listeria and Salmonella.

attack on bacteria

And this is how the attack on the bacteria works: the phage sticks to the bacteria and injects its DNA, its genetic information. This forces the bacteria to make dozens of copies of the phage. The bacteriophages explode and spread to infect other bacteria. And the game starts again. Ideally, until more bacteria are gone. When Micreos employees check if their phages can serve as a problem-solving for a food manufacturer, the procedure is always the same: Two copies of the food are contaminated with the problem-causing bacteria. The swabs are then placed on two plates of feeders in the incubator. After 24 hours, there is usually a significant difference in colonization. Few colonies in the phage sample and many in the untreated control sample. The treatment is working. Dr. Stephen Huggins, Scientific Director of Micreos, is not only completely convinced of his product, but is excited: “The phages are very adept because they are very specific. That means they only kill a very specific type of bacteria. And there, where there are good bacteria, they are not killed – as It is the case in cheese or yoghurt. This allows phages to be used in a very specific way.”

germ protection wall

And this is how phages can soon be used in Germany: in the production of sausages, the intestines can be impregnated with antibacterials. Phage will only be used on food surfaces. As a protective barrier against germs. This technique may also be useful in the production of smoked fish. One can spray the final product with a phage solution. While this technology has been standard in food production in the USA, Canada, Australia and Switzerland for years, it is not allowed in most EU countries, including Germany. At the University of Hohenheim in Stuttgart, microbiologist and safety officer for genetic engineering Dr. Wolfgang Beyer. He knows the reason for this “backwardness”: “Among other things, this has to do with the fact that phages can be used for completely different things: in addition to phage therapy in medicine and disinfection of laboratories and contaminated areas, also for disinfection of foodstuffs. For all applications, the process of Consent is very different and complex. Both in Germany and in the European Union.”

Danger from phages?

But there are also medical concerns about the use of phages on an industrial scale: There is a type of phage that does not immediately judge bacteria to produce phages, but instead integrates their genome first into the genome of the bacterium. If the bacteria reproduce, they duplicate the genome of the virus at the same time. A very elegant method of genetic reproduction. But it makes this type of phage dangerous. Because when viruses wake up from their genetic hibernation, they can take dangerous parts of the bacterial genome with them. Also resistance genes and toxins. and pass them en masse to other bacteria. Wolfgang Beyer knows these concerns. But he does not share the assessment that there is a real problem here: “This type of phage, which can integrate its genome into the bacterial genome, would not be used in the food industry. You can rely on a phage there, which, in fact, the bacteria can only feed. And there is a very small possibility of transmission Dangerous bacterial genes.”

Staff at Micreos assume that there will be approval of this process in the European Union in 2017. In the future, viruses on food could also be beneficial to consumers in Germany. An idea you have to get used to.

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