ABSTRACT
Beer is an inherently microbiologically stable product and therefore not subject to the myriad of spoilage microorganisms that can colonize most foods or nonalcoholic beverages. This chapter reviews the predominant spoilage organisms, outlines the available technology for detecting and identifying these organisms, and considers the role of the brewing microbiology laboratory in dealing with these problems and assuring consistent endproduct quality. Wild yeasts are generally defined as "yeasts not deliberately used and not under full control". Airborne microorganisms colonize barley in the field soon after the ears emerge from the leaf sheaths. Fortunately, of the many thousands of bacteria that have been described, few are of concern to the brewer. The lactic acid bacteria are the only group of Gram-positive bacteria likely to cause a significant threat to beer. The heterofermentative bacterium L. brevis is the most common beer spoilage bacterium and is detected at high frequency in beer and breweries.
