Background: Rural communities who consume unpasteurized and traditional
fermented milk products on a regular basis, have a low prevalence of
allergic diseases. Lactic acid producing bacteria present within these
products, is postulated to have an allergy protective role against
atopy. Objective: To characterize and compare the bacterial microbiota
of fresh unpasteurised cow’s milk and to explore the effect of milk
fermentation (commercially and traditionally fermented) on the bovine
milk microbiota. Methods: Raw, unpasteurized cow’s milk was collected
from urban and rural farms. Another sample, collected from a rural farm,
was left to ferment naturally. Three different brands of commercially
fermented milk samples were also analysed. The V3 and V4 regions of the
16S rRNA gene were amplified to assess microbiota composition. Results:
Urban and rural fresh milk had the highest microbiota alpha diversity,
and commercially bought fermented milk products, the least. Commercially
fermented milk was consistently dominated by lactic acid producing
bacteria, belonging to the phylum Firmicutes, while homemade fermented
milk comprised of approximately 50% Firmicutes and 50% Proteobacteria.
The relative abundance of several organisms differed between fermented
and unfermented milk. Lactococcus lactis dominated all milk products,
however its relative abundance was lower in fresh milk compared with
fermented milk. Lactobacillus paracasei and Streptococcus infantis were
abundant in traditionally fermented milk, but absent in commercially
fermented products. Potential pathogens were demonstrated in fresh and
home fermented milk. Conclusion: Commercially fermented milk can be
promoted as a safe and possible allergy protective complementary feed
from 1 year of age.
Bacterial microbiota composition of fresh unpasteurized cow’s milk and home‐made and commercially available fermented milk products
