Research studies have shown that in beer dispense systems, the surface of the pipes are prone to bacterial attachment and accumulation.
Bio-films are then formed as the attached microorganisms secrete extra cellular polymers such as polysaccharides and glycoprotein's. It is further established that microbes (such as bacteria and yeasts) embedded in such bio-films are well protected against cleaning and sanitation.
It has further been shown that the places where the bio-films develop are exactly those places that are difficult to clean.
In beer dispense systems it is therefore critical to remove contamination in the pipes before bio-films are able to develop enough to strength to withstand the cleaning process.
This underpins the normal weekly cleaning regime recommended. This enables pipes to be cleaned completely with cleaners, which do not destroy the pipe surface, which would lead to increased anchorage of colonies and therefore bio-film.
The growth varies with the ph level of the beer, the particular hop acids, the alcohol level, the degree of fermentation, oxygen content and many other factors. Bio-film development is therefore accelerated by sources of nourishment for the bacteria, which enable the generation of higher levels of extra cellular polymers, which develop into bio-films.
Organisms which cause spoilage in beer dispense systems are more active at the places in the system where higher oxygen levels and higher temperatures are prevalent. The critical areas are also areas of ingress in an otherwise closed system for bacteria and wild yeasts. These areas are at the keg connector, the fobmeter and severely at the front aperture and the adjacent pipe work.
The pictures below show how quickly the bacteria can multiply and grow
when these kegs had been disconnected.
The images clearly show how easy the bacteria can take over your system and subsequently ruin your beverages.