Curbing the growth of beer-spoiling bacteria

IN many industries, silver nanoparticles have found their way in the production of various materials, from containers to clothing, as a means to stop the growth of bacteria. The silver ions, which flow from the nanoparticles when oxidised, are toxic to numerous types of microbes. Scientists used to believe that the nanoparticles themselves were the lethal weapon, but research has shown that ionisation has to take place for the silver to do its clean-up job.

The beer and brewing industry is one that can benefit well with the use of silver ions particularly in tubings and fittings. Even in an environment that is inhospitable to most bacteria because of its low pH level and ethanol concentration, a number of microganisms are still capable of growing in and deteriorating beer. In addition to obligate beer spoilers, some bacteria, yeasts and moulds come into contact with the beer spoiling bacteria in biofilms whose presence gives an insight into the hygiene conditions of a brewery. Biofilms grow on equipment components and in niches that are difficult to clean, thereby contaminating the product and providing ideal growth conditions for a multitude of germs. Once colonised in the filler surrounding, for example, these germs can consistently get into the product and cause damage (Streukontamination). Hence, manufacturers must always check for bacteria and yeasts that contribute to the formation of biofilms. Strains of the genera Acetobacter, Wickerhamomyces, Lactobacillus and Pseudomonas can occur as biofilm colonizers and potential spoilage organisms not only in beer production but also in other beverages including wine. However, the formation of biofilms and micro-organism aggregations can be avoided by regular and thorough cleaning of plants and breweries.

Using antimicrobial coatings in particular have shown to be useful in curbing the growth of unwanted microbes.The Flexelene antimicrobial tubing from Eldon James Corporation, for example, inhibits the spread of pathogenic bacteria, moulds, fungi and algae, and prevents the formation of biofilm through the slow release of silver ions coming from the inner liner. The RoHS-compliant product is applicable not only in food and beverage processing, but in hospital settings as well.

Recently, the product received validation on its effectiveness against microbes, from the Research Centre Weihenstephan for Brewing and Food Technology (Forschungszentrum Weihenstephan) of the Technische Universit?t München in Germany, considered the world’s leading specialist for analysis and research on topics related to beer and food. Eldon James had contracted the research centre to measure the quality of its Flexelene antimicrobial tubing.

The study determined the antimicrobial activity of the Flexelene Silver Tubing against beer spoiling micro-organisms involved in the formation of biofilms in the brewing environment. It also examined the impact of the rubber material on the smell and taste of beer and alcohol. For this, researchers chose four industry isAir Zoom Pegasus 34