The Control of Microbial Spoilage of Beer*

Abstract

Controlling microbial spoilage of beer is best achieved by elimination of sources of contamination. However it must be realised that the brewing process is not aseptic and the occasional chance contaminant will often be encountered. The effects of such events can be minimised by reducing the susceptibility of beer to spoilage and by the use of techniques capable of rapidly determining low numbers of contaminant organisms before any harm is done. A number of rapid methods have been available to the brewing industry for some years but all are hampered by a lack of sensitivity. Consequently, a number of techniques for concentrating micro-organisms prior to testing have been investigated. The most effective was membrane filtration modified by the use of top-pressure and relatively high temperatures. On the spoilability front, studies of the role of beer components such as dissolved carbon dioxide and phenolic compounds have been carried out. These materials reduce the susceptibility of beers to spoilage.