Soil Films in the Beverage Industry: A Review

Abstract

This article provides an overview of the formation of soil films, their composition, effects and control measures that can be applied in the beverage industry, focusing on the negative aspects of their formation. The positive aspects utilised in bioreactors and fermentation reactions will not be reviewed here. Soils gain access to equipment surfaces and these form soil films that are an assembly of microbial cells, organic and inorganic foulants, irreversibly attached to a surface, and enclosed in an extracellular polymeric substance (EPS) matrix. The EPS is vital in the structure and functioning of different soil film communities. Soil films are responsible for the deterioration of water and corrosion in water distribution systems, food contamination, reduced product quality in the beverage industry, infection on medical surfaces, plaque build up on teeth, increase in fuel costs on ships, decrease in heat transfer in heat exchangers and deterioration of metal due to microbial activity during microbiologically influenced corrosion (MIC).

Competitive inter-species interactions underlie the increased antimicrobial tolerance in multispecies brewery biofilms

“…It should be noted, however, that our analysis only included culturable species and could not distinguish between species that have the same morphology on the PCA plates. Nevertheless, harmless biofilms still cause visual slimy contaminations that deteriorate the general image of hygiene in the brewery, can cause corrosion and reduce process efficiency [39] and might act as primary colonizers that prime the surface for subsequent colonization by beer spoilers [38,39].…”

“…Samples taken before CIP were collected at least 12 h after the last cleaning, whereas the samples taken after CIP were collected within 3 h after cleaning. The sampling protocol is similar to protocols used by other studies that isolated brewery biofilms [37,38]. Sterile cotton swabs (Deltalab) were used for collection of biofilm material from approximately 25 cm 2 on different surfaces in the bottling plant, filtration room, and storage room.…”

“…In the brewing industry undesired biofilms can be associated with spoilage organisms, cause corrosion and reduce process efficiency. Several stages of the brewing process, including pasteurization, storage, and bottling of the beer, are known to be affected by biofilms and the eradication of these biofilms remains highly challenging [37][38][39]. Improved understanding of antimicrobial tolerance is thus a prerequisite for designing more effective brewery sanitation procedures.…”

Draught beer hygiene: cleaning of dispense tap nozzles

“…). In addition to reviews there is growing interest and awareness of biofilms in packaging operations and on surfaces across a microbrewery . Further, signalling via acyl homoserine lactones has been demonstrated in bacteria colonizing brewery process surfaces .…”

Decision letter: Mapping microbial ecosystems and spoilage-gene flow in breweries highlights patterns of contamination and resistance

“…Beer is protected from wholesale microbial contamination through its alcoholic, low-pH, and antimicrobial properties, and modern sanitary technologies and practices minimize the threat of spoilage organisms that have evolved specifically to grow in beer (Bokulich and Bamforth, 2013). Nevertheless, biofilms and other environmental reservoirs remain potential sources of microbial contamination in breweries (Timke et al, 2005;Storgards et al, 2006;Timke et al, 2008;Mamvura et al, 2011;Matoulkova et al, 2012). As wort is boiled prior to fermentation, the primary reservoir for spoilage microorganisms in beer production eLife digest Many microbes-including bacteria and fungi-can affect the food and drink we consume, for better and for worse.…”