Comparison of enrichment media for routine detection of beer spoiling lactic acid bacteria and development of trouble-shooting medium for Lactobacillus backi

Abstract

The beer spoiling lactic acid bacteria (LAB) are known to have a substantial financial impact in the brewing industry and their rapid detection is essential. Thus more effective media for the cultivation of LAB in both routine quality control and special trouble-shooting situations are needed. In this study, different media were tested for the routine detection of LAB at a commercial brewery. The results showed that the use of an enzyme controlled glucose delivery system, in combination with beer-MRS medium, can significantly decrease the total analysis time. For more effective trouble-shooting in contamination incidents a trouble-shooting media, including the reducing agents L-cysteine-HCl and sodium bicarbonate, was developed. The presented medium was shown to improve the growth of beer spoiling L. backi and L. brevis, and is thereby suggested for faster detection of these strains at the breweries. © 2010 The Institute of Brewing & Distilling.