Mammalian milk was once thought to be free of bacteria, but it is now well understood that milk has its own microbiome, or community of bacteria. Although only recently “discovered,” microbes were likely one of milk’s original ingredients and have an evolutionarily ancient relationship with their mammal hosts. Many bacterial species are likely common to all. But because some bacterial strains could potentially benefit infant health by promoting the growth of beneficial bacteria in the gut or enhancing infant immunity, there may have been numerous opportunities for the evolution of species-specific milk bacterial communities. Does each mammal, including humans, pass on its own unique mix of bacterial strains in milk or is there a more general milk microbiome shared across mammals? Read More...