Colonization of the human gut by bovine bacteria present in Parmesan cheese

Abstract

The abilities of certain microorganisms to be transferred across the food production chain, persist in the final product and, potentially, colonize the human gut are poorly understood. Here, we provide strain-level evidence supporting that dairy cattle-associated bacteria can be transferred to the human gut via consumption of Parmesan cheese. We characterize the microbial communities in samples taken from five different locations across the Parmesan cheese production chain, confirming that the final product contains microorganisms derived from cattle gut, milk, and the nearby environment. In addition, we carry out a human pilot study showing that Bifidobacterium mongoliense strains from cheese can transiently colonize the human gut, a process that can be enhanced by cow milk consumption.

Bifidobacterial Distribution Across Italian Cheeses Produced from Raw Milk

“…In contrast, cluster BifB is characterized by a dominance of B. crudilactis (average of 92.9%) with much lower average abundance of B. mongoliense (average of 4.0%) ( Figure 2). Notably, these findings confirm previous observations about the adaptation of B. crudilactis and B. mongoliense to grow and survive in milk and cheese environments [22,23,30,31], and reveal the widespread distribution of these bifidobacterial species in cheeses produced from raw milk derived from cow, buffalo, sheep, and goat.…”

“…For these reasons, bifidobacteria are now widely recognized as key members of the human gut microbiota, being frequently used as functional ingredients in food products. Some bifidobacterial species have been reported to grow and survive in milk and dairy products [22,23]. This observation is supported by the genomic dissection of species-specific metabolic capabilities across the whole genus that highlights a range of bifidobacterial species possessing genes dedicated to the utilization of carbohydrates typically found in dairy matrices [19].…”

“…This observation is supported by the genomic dissection of species-specific metabolic capabilities across the whole genus that highlights a range of bifidobacterial species possessing genes dedicated to the utilization of carbohydrates typically found in dairy matrices [19]. Furthermore, a recent strain-level assessment of horizontal transmission of bacteria across the Parmigiano Reggiano cheese production chain revealed that a bifidobacterial species harbored by dairy cattle and their associated environment are transferred to cheese produced from their raw milk, where it may colonize and persist in the consumers' gut [23]. These data not only highlight that bifidobacteria may modulate the cheese microbiota, thus perhaps participating in the development of the organoleptic features of cheese, but that they may also modulate the gut microbiota of human consumers.…”

A Guide to Diet-Microbiome Study Design

“…Consideration for the microbial load of a dietary pattern is important because the engraftment of non-pathogenic food-borne bacteria depends, in part, on other dietary components. For example, higher abundances of parmesan-cheese-associated bacteria are present after consumption of milk products (61). Ideally, we need to consider these microbial features of diet when planning and analyzing microbiome-diet studies.…”

Gut microbiota alterations due to fecal transplant

“…Metabolic functions of the gut microbial consortia are associated with support of physiological homeostasis, synthesis of vitamins and amino acids, short-chain fatty acids and other essential functions [Belkaid and Harrison, 2017]. Development of gut microbiota starts from the moment of birth and may depend on some important events, a few of which can be distinguished: the way of birth (vaginal or cesarean section), maternal microbiota transmission, feeding (breastfeeding or artificial) [Bäckhed et al, 2015;Ferretti et al, 2018;Shao et al, 2019], early antibiotic therapy [Korpela et al, 2016] et al Moreover, bacteria could enter the intestines from the environment with food [Milani et al, 2019] and drinking water [Hansen et al, 2018]. These factors form a microbial community that may contain both common and unique members for different people.…”