Microbiological stability of beer

Gram-negative spoilage bacteria in brewing

“…Conventional methods for detection of spoilage microorganisms in beer and other beverage generally involves pre-enrichment of sample with a nonselective medium, followed by enrichment on selective or differential agar (Hill, 2009). There are numerous media described for isolation and identification of AAB bacteria, but no single medium has been found to be effective in supporting the growth of all AAB, and selectivity of the medium is variable for different strains (refer Table 8.3).…”

Hygienic design and Cleaning-In-Place (CIP) systems in breweries

“…However, the presence and prevalence of foreign microorganisms in the brewery should be minimised through appropriate brewery design and cleaning practices, as the presence of contaminating microorganisms can cause stuck fermentations and affect product yield and beer flavour, consequently affecting brewery profitability (Hill, 2009). Contamination can also occur through the brewery process pipework or vessels if they have not been appropriately designed for hygiene.…”

Review: Gram Negative Bacteria in Brewing

“…Conventional methods for detection of spoilage microorganisms in beer and other beverages generally involves pre-enrichment of the sample with a non-selective medium, followed by enrichment on selective or differential agar [17].…”

“…There are several rapid detection methods available for detection of these microorganisms based on techniques such as Immunoassay, Ribotyping, PCR based methods, RT PCR based methods, Florescence and Luminescence based molecular probes [17] [88] [108] [111]. Although several methods are available in brewing literature, the actual use in commercial brewing microbiological labs is still limited to conventional plating and a few rapid detection methods.…”

“…Other significant Gram negative aerobic and facultative anaerobe beer spoilers belong to genera Acetobacter, Zymomonas, Selenomonas, and Obesumbacterium. Certain Enterobacteriaceae such as Rahnella and Hafnia have also been reported in brewing environments [15]- [17]. Wild yeasts in brewing are generally described as "yeast strains which are not deliberately introduced and grow uncontrolled in the brewing process" [18].…”