“We are talking about the largest investigation into microbes in food ever conducted. Now we will be able to use this data to better understand how the quality, conservation, safety and other specificities of foods are linked to the microbes they contain”. This is what Nicola Segata, computational microbiologist at the University of Trento and the European Institute of Oncology (IEO) in Milan and co-senior author of the study that revealed the microbiome (microbiota, or the set of microorganisms found in a given environment) present in the food we eat, told Today.it.
The latter, in fact, contains microbes capable of influencing both the quality of food and (precisely) the heritage of microorganisms specific to each person: the human microbiome. To characterize the food microbiome in the most complete and efficient way, the international research team coordinated by Cibio (Department of Cellular, Computational and Integrated Biology) of the University of Trento has exploited metagenomics, an approach that allows to simultaneously sequence the entire genetic material present in a sample (in this case, food samples).
“Food Microbiome” Database
After analyzing 2,533 different foods (including 1,950 metagenomes sequenced for the first time) from 50 countries, the international research team reconstructed 10,899 genomes of food-associated microbes – half of which belong to previously unknown species – classified into 1,036 bacterial species and 108 fungal species. The research then showed that food-associated microbes make up an average of up to 3 percent of an adult’s gut microbiome (and 56 percent of a child’s gut microbiome).
And again, the study – truly innovative, considering that in practice the microbes present in food are grown one by one in the laboratory, with a decidedly slow process and not suitable for all types of microorganism – whose results are published in the biology journal Cellnoted that foods of this type tend to host similar but not identical microbes (with greater variety among dairy products). Although few potentially pathogenic microorganisms have been identified (as the Humanitas clinical institute explains on its website, “pathogenic microorganisms are agents of different nature, responsible for the onset of a pathology. Examples include viruses, bacteria and fungi”), the research has therefore identified some microbes that are less desirable for their impact on the flavor or preservation of food.
This information could be very useful both to improve the quality of what we eat and to support those who deal with food regulation (or must determine the identity and origins of a food). Understanding the food microbiome can therefore have a series of implications for human health. Some of the microbes we eat, in fact, could permanently access our microbiome.
Study every type and variant of bacteria
Segata further explains: “In many cases, the food microbiota is a crucial component of the food itself. For example, in fermented foods, the final properties are determined by bacteria that produce specific compounds that are characteristic of the food from an organoleptic point of view. For this reason, whether the fermentation process is triggered by bacteria that are initially present in the food or are added specifically, the type of bacteria responsible for the fermentation influences the process in progress and, consequently, the types of compounds produced”.
Thus, systematically studying every type and variant of bacteria present (or, indeed, added) in foods can help to understand which strains or species are associated with the quality of the resulting food. “And this is true for both fermented foods and all those – and they are the majority – that contain microorganisms inside them”, continues Segata. Who concludes: “The food microbiota can also prevent or favor the colonization of bacteria considered pathogenic, assuming in fact a decisive importance also for the safety of the food itself”.