Every time we eat food, millions of microorganisms pass through our digestive system and a small part stays with us, sometimes to help us process nutrients. Knowing how many of these bacteria, fungi and yeasts reside on us and what species they belong to seems like an unattainable goal, but a mega-study in which Spanish researchers have participated brings us closer to the answer.
Is it safe to use a microwave to sterilize? A scientific study has discovered bacteria that survive inside
In a work published this Thursday In the magazine Room, Member of Master EU Consortiumtogether with researchers from 14 countries, analyzed the set of microbial genes present in 2,533 foods from 50 countries (the so-called metagenome) and have identified 10,899 microorganisms associated with them. By comparing them with the genomes of microbes that usually appear in our intestines, the authors have an approximate answer to the initial question: about 3% of the microbes present in these foods appear in the intestines of adults, while in infants they represent an average of 56%, since their diversity is still much lower.
“It might seem like it’s only a small percentage, but that 3% may be extremely relevant to its function within our bodies,” he says. Nicola Segata“With this database we can begin to study on a larger scale how the microbial properties of foods can affect our health,” said study author and co-senior author of the paper, computational microbiologist at the University of Trento.
reservoir of germs
Another relevant aspect of the results is that almost half of the more than 10,000 microbes found in food, classified into 1,036 bacteria and 108 fungi, belong to unknown and non-cultivable species, known as ‘microbial dark matter’ (Microbial black matter(Information that could help the food industry and smaller producers produce more consistent and desirable products, as well as guide food regulators in defining which microbes should be in certain types of food and which should not, even contributing to certifying its origin and quality.
This may only seem like a small percentage, but that 3% can be extremely relevant to its function within our bodies.
Nicola Segata
, Computational microbiologist at the University of Trento and co-lead author of the article
“We can now begin to use this context to better understand how the quality, preservation, safety, and other characteristics of foods are related to the microbes they contain,” says Segata. “Food microbiologists have been studying foods and performing food safety testing for over a hundred years, but we have made little use of modern DNA sequencing technologies,” adds co-senior author and microbiologist. Paul Cotter. “This is the starting point of a new wave of studies in that area in which we make full use of the available molecular technology.”
Jerks off into an Amazon
Many of the foods whose microbes have been sequenced are of Spanish origin, including several Asturian cheeses and products such as cecina and chorizo from Leon or blood sausage. “Above all, there are a lot of dairy products and we have also introduced some foods from the meat industry, which we work with,” he explained. elDiario.es Avelino Álvarez OrdóñezResearchers from the Department of Hygiene and Food Technology of the University of Leon and co-authors of the study, which also involved other Spanish institutions such as the Institute of Agricultural Chemistry and Food Technology (IATA-CSIC) or the Institute of Dairy Products of Asturias (IPLA-CSIC). In general, dairy products were overrepresented in these metagenome samples, with 65% of these products in all samples, while fermented beverages accounted for 17% and meat for 5%.
Many of the foods analysed are of Spanish origin, including several Asturian cheeses and products such as cecina and chorizo from Leon or blood sausage.
In Álvarez Ordóñez’s opinion, the most remarkable thing is the discovery of such a high percentage of microbes from species that are not yet known or have not been observed in food. In some ways, he admits, it was as if they were searching through a pantry of potential resources – with applications in biotechnology or the food industry – that are hidden in everyday foods that have never been analyzed in detail. “In the field of food microbiology we have traditionally studied microorganisms using culture techniques, but they are only a very small fraction,” he says. “This result has shown us a much greater diversity than we expected and invites us to continue characterizing and exploring these bacteria, until we are able to grow them and see their function in food.”
This reservoir of bacteria in food, like the microscopic and unknown Amazon forest, could give rise to new strains that give rise to new types of cheese or fermentation processes that could range from bread, yogurt or beer. And Álvarez Ordóñez’s team is working in parallel on the study of microbial resistance to antibiotics present in these microorganisms, an issue very relevant for public health in the medium term. “The general population may have the idea that we are interested in foods free of microorganisms to stay safe, but we know that the vast majority can be beneficial,” he comments. “Fermented foods are gaining more and more interest, so having access to a wider list of those good microorganisms opens up many possibilities.”
“We are what we eat”
To Ignacio López-GoniProfessor of Microbiology at the University of Navarra, this is a very detailed article, with an impressive amount of information and data. “What has caught my attention the most is that about 50% of the microorganisms they found are non-cultivated, that is, those about which we know very little,” he explains. “And, 50% of them are unknown and food-specific.” Although we already know that if we apply these techniques to any ecosystem we find thousands of non-cultivated microorganisms, it seems to be a good starting point for future work. “Perhaps it can help us in the future to improve food control techniques, devise new fermentation strategies and, even, to design new probiotics that we did not know about until now,” he summarizes.
Perhaps it can help us improve food control techniques, find new fermentation strategies, or design new probiotics.
Ignacio López-Goni
, Professor of Microbiology at the University of Navarra
Cristian Diaz-MunozThe postdoctoral researcher at the Gastrointestinal Genetics Lab, CIC Biogun – BRTA, believes that this work has a direct impact on important and urgent aspects such as food safety. “Not only does it confirm the popular saying that ‘we are what we eat’, but it also confirms the foundations on which quality probiotic foods are established that contain microorganisms with a proven ability to colonize the digestive tract and have a positive effect on intestinal health.”, explains SMC. And this highlights the importance of yeasts as an essential part of the human microbiota. “Yeasts are ubiquitous in our diet (beer, cheese, wine…) but are often overlooked in studies on intestinal health and microbiota,” he emphasizes.
Baltasar Mayo PérezCSIC research professor at the Institute of Dairy Products of Asturias (IPLA-CSIC), there is no doubt that this is the largest scientific effort ever undertaken. “One of the first future research tasks will be aimed at recovering these new taxa and carrying out selective cultures to characterize them in depth, including tests that will allow to anticipate a practical and safe use,” he explained in his statements. SMC. “Only in this way can these new microorganisms be used as fermenters or supporting cultures in the fermentation of the foods from which they have been isolated,” he concluded.