New research from DTU (Technical University of Denmark) could revolutionize how the food industry produces milk-based yogurt—making it both cheaper and more sustainable

A research team at the DTU National Food Institute has developed a new method for yogurt production, sparked by a simple question.

• We’ve been studying lactic acid bacteria and their energy metabolism for years, but one day it hit us: What if we let the bacteria ferment without growing? It was a bit of a ‘eureka’ moment,” says Associate Professor Christian Solem, who has researched lactic acid bacteria for over 25 years, in an article on DTU Food Institute’s website.

The research has major potential, as it’s estimated that each person worldwide consumes nearly 12 kilos of yogurt per year on average.

The method has been tested on a small scale in DTU Food Institute’s lab, but the researchers see no reason why it couldn’t be directly implemented in dairy production. It doesn’t require new technology—just a simple adjustment to the temperature control in the production process.

• Dairies could, in principle, start using the method tomorrow. We haven’t found any downsides, except that it takes one or two hours longer—and you get a product that’s both more stable and more sustainable, says Christian Solem.

Currently, yogurt is produced by adding a relatively large amount of yogurt bacterial culture to milk, which is then fermented for 4–6 hours at 42°C. Once the desired acidity is reached, the yogurt is cooled. But this process has several known challenges:

• High costs of bacterial cultures
• Limited shelf life
• So-called “post-acidification,” where the yogurt continues to become more acidic during storage, negatively impacting quality and shelf life

With the new method, researchers use only 20% of the usual amount of bacterial culture. The milk is fermented at 42°C as normal, but the temperature is then raised to 51°C for a couple of hours. At this point, the bacteria stop dividing—but they continue to produce lactic acid.

• It’s like putting the bacteria on a treadmill—they don’t go anywhere, but they’re still working. That means we can control the fermentation process while avoiding unwanted post-acidification, Christian Solem explains.

The 51°C phase also acts as a gentle pasteurization step.

• We eliminate up to 99.9% of the yeast cells and mold spores that would otherwise significantly reduce yogurt’s shelf life,” Solem adds.

You can read the full article here.

Photo: Micheile Henderson, Unsplash