Butter found pathogenic bacteria
Russian scientists first read the genome of microbes in butter of different brands and found a number of opportunistic species, including dangerous for children. The study is published in the journal Foods.
Dairy products — the excellent environment for the growth of many dangerous bacteria, e.g. Salmonella. In Russia, the product quality according to established Standards, but even at observance of all norms of production, to ensure the absence of microbial contamination is impossible, as it often happens that the microorganisms can be detected only with the involvement of the latest scientific methods.
Scientists from the Voronezh state University and Voronezh state University of engineering technologies with high-throughput sequencing is analyzed 21 samples of different brands of butter: take one gram of the product, finely sliced it and added to a special culture medium in Petri dishes. The grown bacterial cells were sequenced, that is "read" their genome on a special device.
The authors used next generation sequencing — a set of methods for the determination of DNA sequences or RNA, allowing for once to set multiple genomes.
In General, the researchers found 94 kinds of bacteria, including opportunistic — which can be dangerous under certain factors, for example, when an unbalanced diet or a weak immune system.
"Identification of conditionally pathogenic microorganisms using high-throughput sequencing showed a need to optimize methodology to detect dangerous bacteria in food. We first demonstrated that the oil is a good medium for the growth of opportunistic species" — presented in a press release of the Russian science Foundation, which supported the study, the words of the head of the research team Evgeny Popov, doctor of technical Sciences, Professor of the Department of service and catering business of the Voronezh state University of engineering technology.
Interestingly, beneficial lactic acid bacteria producer Lactococcus and Lactobacillus, which are part of some cultures, prevailed only a quarter of the samples. The oil was heaviest contaminated with bacterium Bacillus cereus, can produce toxins and cause diarrheal syndrome. To researchers surprise the presence in the oil Cronobacter sakazakii — previously, it was recognized that this bacterium may have children up to year to cause sepsis, meningitis or enterocolitis with severe complications and even death.
According to the authors, studies of bacteria in the butter, until this has been given insufficient attention, as it was believed that the fatty medium prevents rapid growth of microbes. In addition, identification of microorganisms in oil requires, unlike regular milk, additional sample preparation, which complicates its analysis. In the few works on determination of microbial species from butter, mostly used classical approaches, for example, epitaxial growth on a special nutrient medium, which includes changing the color of the indicator, and not apply modern molecular methods.
The results of the study emphasize the need for strict quality control of dairy products with high fat content and demonstrate how modern methods to achieve these goals, scientists say.