Fatty acid analysis and spoilage potential of biofilms from two breweries

Aim: The microbial composition of biofilms from different locations of beer bottling plants were compared based on fatty acid profiles and correlated with the product- spoiling potential of these biofilms. Methods and Results: The whole cell fatty acid profiles of 78 biofilms from bottling plants of two breweries were analysed. About half of the lipid profiles were dominated by oleic and linoleic acid, which refer to a high proportion of yeasts. In addition, more than half of all samples contained dimethylacetals indicating the presence of strictly anaerobic bacteria. Typical fatty acids for potentially beer- spoiling genera were detected in three biofilms. The majority of the biofilms contained no beer- spoiling organisms, as shown by inoculation experiments in beer. Conclusions: Biofilms from different locations of bottling plants were different with respect to their microbial composition. Potentially product- spoiling populations could be detected in a small number of samples. Significance and Impact of the Study: Biofilms on industrial plants can be characterized by a fast and cultivation- independent method with respect to overall microbial composition and presence of potentially product-spoiling micro- organisms.