The added benefits of bacteria from the cheese-making process

Researchers in the Food Microbial Sciences Unit at the University of Reading tracked the microbial and biochemical changes that occurred as three locally made Oxfordshire cheeses matured. Their findings suggest that some of the bacteria responsible for developing each cheese’s unique character may also be useful to the people who eat them.

The study, published in ACS’s Food Science & Technology, focused on three varieties made by Nettlebed Creamery in Oxfordshire. These included a soft white rind cheese aged for a little more than a week, a washed rind semi-soft cheese that matures over several weeks, and a semi-hard cheese aged in hay for about nine months.

Lead author Sabrina Longley, a PhD researcher in the Department of Food and Nutritional Sciences, said: “Good cheese is delicious, and the artisan varieties we studied are full of microbial life that could have benefits to your gut health.

“The aging process creates more complex aromas and textures through the work of an army of helpful bacteria. The matrix of fats and proteins in the cheese may also help protect the bacteria as they travel along the digestive tract, making cheese an excellent vehicle for delivery of probiotics to the gut.”

To follow how the cheeses changed over time, the researchers collected samples at multiple stages of maturation and analysed both their bacterial communities and chemical composition.

All three cheeses contained bacteria with recognised probiotic potential, meaning they may help support populations of beneficial microbes in the gut. Streptococcus thermophilus, which is also commonly used as a yoghurt starter, remained dominant in the semi-soft and harder cheeses throughout the maturation process. Lactococcus lactis was detected in all three cheeses from start to finish.

The washed rind cheese and hay-aged cheese also contained Propionibacterium freudenreichii. This bacterium produces propionic acid, a compound associated with anti-inflammatory properties, reduced cholesterol synthesis and appetite regulation.

Cheese rinds may have prebiotic potential

Cheese lovers who enjoy eating the rind may have another reason to do so. The white mould Penicillium candidum, which forms the characteristic rind on the soft cheese studied, produces chitin, a dietary fibre that may act as a prebiotic.

Prebiotics serve as food for beneficial bacteria in the gut, potentially encouraging positive changes in the gut microbiota.

The hay aging process also appeared to have a striking effect on the harder cheese. As it matured, the diversity of bacterial species increased substantially. The fully mature cheese contained nearly four times as many bacterial species as the same cheese did earlier in the aging process.

Mature cheese contained little lactose

The researchers also found that lactose, the sugar in cow’s milk that some people have difficulty digesting, was almost entirely absent from all three cheeses once they had matured.

During fermentation, lactic acid bacteria broke down most of the lactose, leaving very little behind by the time the cheeses were ready to eat.

Sabrina Longley is also a cheesemaker at the independent Nettlebed Creamery in Oxfordshire, which part-funded the research. She is carrying out her PhD research part-time with support from a University of Reading regional bursary, a program designed to help people from the local area pursue research studies.

The researchers caution that more work is still needed. Further research (dietary intervention trials) will be necessary to determine how these bacterial populations behave and change within the gut microbiota after the cheeses are consumed, as well as what effects they ultimately have on the human body.

Image credit: iStock.com/Zulfiska