WORT ENTEROBACTERIA AND OTHER MICROBIAL POPULATIONS INVOLVED DURING THE FIRST MONTH OF LAMBIC FERMENTATION

Abstract

Lambic is a special type of Belgian beer obtained by spontaneous fermentation. The micro‐organisms occurring during the first month of lambic fermentation were counted using several selective media. During this period a mixed flora is present in which the Enterobacteriaceae predominate. They were isolated from samples of lambic of different ages originating from different breweries and identified using the minitek identification system. Much variation may occur in types of Enterobacteriaceae: Klebsiella aerogenes, Enterobacter cloacae, E. aerogenes, Escherichia coli, Citrobacter freundii, A‐D group bacteria and Hafnia alvei are found during the first month of fermentation. E. cloacae is found most frequently followed by K. aerogenes. After 30 to 40 days all Enterobacteria die off because of the activities of yeasts. Lactic acid and acetic acid bacteria are found in very low numbers during the first month of fermentation; Staphylococci and Streptococci are not present.