TITLE:
Review: Gram Negative Bacteria in Brewing
AUTHORS:
Paradh Ashtavinayak, Hill Annie Elizabeth
KEYWORDS:
Gram Negative Bacteria, Beer Spoilage, Pectinatus, Megasphaera, Acetic Acid Bacteria
JOURNAL NAME:
Advances in Microbiology,
Vol.6 No.3,
March
22,
2016
ABSTRACT: Gram
negative aerobic bacteria such as Acetic Acid Bacteria, which include Acetobacter and Gluconobacter, have historically caused significant problems to brewers.
Although incidences of spoilage have recently reduced as a result of improvements
in beer packaging, these bacteria are still a concern in dispense systems in pub
breweries, public houses and cask conditioned beers. Gram negative facultative bacteria
of the genus Zymomonas can spoil primed
cask conditioned beer and cider. There is a wide range of Enterobacteraeceace which are found within brewery environments and
they serve as indicator microorganisms for hygiene and sanitation. Gram negative
strictly anaerobic bacteria such as Pectinatus and Megasphaera have recently emerged
as a significant threat due to the improvement in reduction of oxygen levels in
beer and an increase in production of unpasteurised beer. Pectinatus and Megasphaera are
sensitive to routine cleaning agents used in breweries, but they can survive and
proliferate in biofilms eventually causing spoilage of beer. This review focuses on Gram negative aerobic,
facultative anaerobic and strictly anaerobic brewery related spoilage bacteria.