Cheese has always felt like a bit of alchemy: milk, a handful of cultures, patience, and suddenly you have something with texture, aroma, and a personality of its own. A new study from the University of Reading, published in ACS Food Science & Technology, pulls back the curtain on that transformation, tracking exactly which microbes are doing the work inside three artisan British cheeses, and what they leave behind that might matter for our gut.
Three Cheeses, One Question
Researchers Sabrina Longley, Glenn Gibson, and Anisha Wijeyesekera studied cheeses made by Nettlebed Creamery in Oxfordshire: a soft, bloomy-rind cheese matured for just over a week, a semisoft washed-rind cheese aged over several weeks, and a semihard cheese matured in hay for around nine months. At several points during ripening, they sampled each cheese and ran two parallel analyses: 16S amplicon sequencing to map which bacteria were present, and 1H NMR spectroscopy to track the chemical changes happening alongside them.
The goal wasn’t just cataloguing microbes for the sake of it. Cheese has long been associated with potential gut health benefits, and the team wanted a mechanistic look at why: which bacteria survive the maturation process, what byproducts they generate, and whether any of that could plausibly carry through to the digestive tract.
An Army of Helpful Bacteria
Each cheese turned out to host bacteria with recognized probiotic potential. Streptococcus thermophilus, the same organism used to start yogurt fermentation, stayed dominant in the semisoft and hard cheeses right through to maturity. Lactococcus lactis showed up in all three cheeses throughout the entire process.
The washed-rind and hay-aged cheeses also carried Propionibacterium freudenreichii, an organism known for producing propionic acid, a short-chain fatty acid linked to anti-inflammatory effects, lower cholesterol synthesis, and appetite regulation. And the white mould responsible for the soft cheese’s bloomy rind, Penicillium candidum, produces chitin, a dietary fibre that may act as a prebiotic, feeding the beneficial bacteria already living in the gut.
As lead author Sabrina Longley, who is also a cheesemaker at Nettlebed Creamery, put it: the fat and protein matrix in cheese may help shield these bacteria as they travel through the digestive tract, making cheese a genuinely useful vehicle for delivering live cultures to the gut.
Hay Aging and a Lactose Disappearing Act
One of the more striking findings involved the hay-aged, semihard cheese. As it matured, its microbial diversity climbed sharply, ending up with nearly four times as many bacterial species as it had earlier in the process, suggesting the hay environment itself seeds and supports a richer community over the long aging window.
The NMR data told its own story: lactose, the sugar in cow’s milk that many adults struggle to digest, was almost completely gone from all three cheeses by the time they reached maturity. Lactic acid bacteria had broken it down over the course of fermentation, which helps explain why well-aged cheeses are often easier on lactose-sensitive stomachs than fresh milk or young cheese.
What This Doesn’t Prove Yet
It’s worth being precise about what this study shows and what it doesn’t. It maps, in detail, which microbes and metabolites are present in the cheese itself at the point of consumption. It does not test what happens once that cheese is actually eaten. The authors are upfront that dietary intervention trials are still needed to see how these bacteria behave once they reach the gut, whether they survive digestion in meaningful numbers, and what measurable effect they have on the wider gut microbiota. So this is a solid piece of mechanistic groundwork, not a green light to treat cheese as a supplement.
Still, it’s a nice reminder that fermentation is a genuinely active, living process, and that the rind you might be tempted to trim off could be pulling its own nutritional weight.
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