Presence of Microbial Contamination and Biofilms at a Beer Can Filling Production Line

Abstract

Contamination of beer arises in 50% of all events at the late stages of production, the filling area. Hereby, biofilms, being consortia of microorganisms embedded in a matrix composed of extracellular polymeric substances, play a critical role. To date, most studies have focused on the presence of (biofilm forming) microorganisms within this filling environment. Our aim was to characterize the microbial status as well as the presence of possible biofilms at a can filling line for beer by determining the presence of microorganisms and their associated matrix components (carbohydrates, proteins and extracellular DNA (eDNA)). Targeted qPCR confirmed the presence of microorganisms at ten sites during operation and three after cleaning (from 23 sites respectively). The evaluation of carbohydrates, eDNA and proteins showed that 16 sites were positive for at least one component during operation and four after cleaning. We identified one potential biofilm hotspot, namely the struts below the filler, harboring high loads of bacteria and yeast, eDNA, carbohydrates and proteins. The protein pattern was different than that of beer. This work deepens our understanding of biofilms and microorganisms found at the filling line of beer beverages at sites critical for production.

Beer Safety: New Challenges and Future Trends within Craft and Large-Scale Production

“…Microbial and fungal contamination ( Pectinatus , Megasphaera , Staphylococcus , Bacillus , Enterobacter , and Zymomonas ) of beer are not well-documented but are not neglected due to important health implications [ 6 ].…”

Microbial Communities in Retail Draft Beers and the Biofilms They Produce

“…With some irony, one goal of these efforts is to create products with scent and flavor complexities that match wild-fermented ales and lambics ( 7 , 8 ). Nevertheless, great care and expense is still applied to minimize contamination by spoilage microbes and to ensure product stability ( 2 , 9 , 10 ).…”

“…Spoilage microbes enter the brewing process primarily from the addition of nonsterile ingredients, air exposure, or contaminated equipment ( 5 , 11 , 12 ). Several spoilage microbes are well known to the brewing community because they are commonly encountered and present a consistent threat; among these lactic acid bacteria (LAB), acetic acid bacteria (AAB), and wild yeasts represent dominant cohorts ( 10 , 12 – 15 ). Interestingly, these types of microbes are also present as desirable members of the microbial communities found in wild fermentations, wherein they can improve flavor balance and impart sour characteristics as the beers are aged to maturity ( 16 – 18 ).…”

Microbial communities in retail draft beers and the biofilms they produce

“…With some irony, one goal of these efforts is to develop create products with scent and flavor complexities that match wild-fermented ales and lambics (3, 4). Nevertheless, great care and expense is still applied to minimize contamination by spoilage microbes and to ensure product stability (2, 5, 6).…”

“…Spoilage microbes enter the brewing process primarily from the addition of nonsterile ingredients, air exposure, or contaminated equipment. Several spoilage microbes are well known to the brewing community because they are commonly encountered and present a consistent threat; among these lactic acid bacteria (LAB), acetic acid bacteria (AAB), and wild yeasts represent dominant cohorts (6)(7)(8)(9)(10). Interestingly, these types of microbes are also present as desirable members of the microbial communities found in wild fermentations, wherein they can improve flavor balance and impart sour characteristics as the beers are aged to maturity (11)(12)(13).…”