Quick bacteria test for beer

A new polymer powder is the key to a faster, simpler method for breweries to detect contamination in their beer.

Pathogens that enter into beer during the brewing process can ruin the pleasure of the drink, resulting in strong variations in taste and smell or causing the beer to become cloudy and sour. Breweries therefore keep a close eye on their production processes to detect harmful microorganisms.

However, conventional microbiological methods can take five to seven days to detect beverage-spoiling organisms, such as bacteria and yeasts. It is often too late at that point to take corrective action.

In collaboration with German company GEN-IAL, researchers at the Fraunhofer Institute for Applied Polymer Research (IAP) have developed a polymer powder that significantly simplifies these tests and shortens the time that they require.

The existing process requires beer to be filtered in special equipment. The bacteria remain on a membrane and are then cultivated for a few days in a special culture medium before they can be examined microscopically.

The polymer powder from the IAP replaces this process: the powder is added to the liquid sample and the powder’s functionalised surface binds the bacteria efficiently. The pathogens adhere to the 100-200 micron powder particles. These can be easily removed along with the microbes in a specially developed system and analysed directly using various microbiological methods. This eliminates the need for the time-consuming enrichment in a nutrient medium.

The test is suitable for much larger quantities of beer and can also test drinks such as milk, juice, cola and red wine.

The membrane filtration method only enabled the testing of up to 1 L of beer at a time. And the method was not suitable at all for beverages such as fruit juices, milk and red wine as the suspended matter they contain quickly clogged the filter. With the polymer powder, tests with 30 L or more are possible, and other beverages can also be tested.