Modified beer spoilage test—growth in lager beer 1 with and without an additional fatty acid source.

Lager beer 1 with and without an additional fatty acid source was inoculated with non-spoiling and spoiling strains. Genome sequenced strains are underlined. TMW 2.1535-SB served as positive control. Four non-spoiling strains were tested for their ability to grow in lager beer 1 with an additional fatty acid source, one of them sequenced and three which were tested for fabZ using PCR. Non-spoiling (fabZ negative) brewery isolates were capable of growing in lager beer 1 supplemented with an additional fatty acid source. Spoilage-groups derived from original beer spoilage test: strong beer spoilage potential (SB)—growth in pilsner, middle potential (MB)—growth in lager beer, weak potential (WB)—growth in wheat beer, no potential (NB)—no growth in test beers. Brewery as isolation source, the presence of fabZ and growth in test beers are indicated by +. IBU = international bitterness units (measure for hop content).