Craft Beer Microflora Identification Before and After a Cleaning Process

Marisa Manzano*, Lucilla Iacumin, Marco Vendrame, Francesca Cecchini, Giuseppe Comi and Stefano Buiatti
Department of Food Science, University of Udine, via Sondrio 2/A, 33100 Udine, Italy.
* Corresponding author. E-mail: marisa.manzano@uniud.it

J. Inst. Brew. 117(3), 343–351, 2011 | VIEW ARTICLE

ABSTRACT
Although beer is a relatively safe product, growth of spoilage microorganisms can cause economic damage. The most effective way to prevent the spoilage of beer is to control contamination with adequate cleaning and sanitation. The aim of this work was to evaluate the microbial flora present both before and after a specific hygiene process was implemented during a brewpub's craft beer production. Various selective and differential culture media methods for the enumeration of beer-spoilage species are available, but they are time consuming compared to modern techniques. The utilisation of accurate molecular methods, added to the routine microbiological analyses, allowed for the fast identification of common environmental contaminants of beer. A poor sanitation plan by the brewer resulted in microbial contamination of the brewpub. This result demonstrates the importance of good sanitation to avoid the presence of undesirable microorganisms in the product. A cleaning-in-place (CIP) method, in operation in many small breweries, could be utilized to prevent the occurrence of such brewery and beer microbial contaminants. In small breweries, the simplest CIP units consist of a single tank and a portable pump. This method requires no additional equipment besides a spraying ball, which is usually included in the design of most tanks.

Key words:
Cleaning programme, craft beer, microbial contaminant, PCR – temporal temperature gradient electrophoresis / denaturing gradient gel electrophoresis.