Isolation and Identification of Potential Beer-Spoilage Pediococcus inopinatus and Beer-Spoilage Lactobacillus backi Strains Carrying the horA and horC Gene Clusters

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).

Section: Soil Films Soil Films In the Brewing Industrymentioning

confidence: 99%

Soil Films in the Beverage Industry: A Review

Mamvura

Iyuke

Cluett

et al. 2011

“…L. paracollinoides, in particular, was shown to exhibit strong beer spoilage ability that is comparable with that of L. brevis and L. lindneri 110 . Although L. paracollinoides was once recognized as a rare beer spoilage species, it has been recently suggested that L. paracollinoides is more prevalent in brewing environments than initially anticipated 45 . The possibility that novel species become widespread poses a threat to the brewing industry that must maintain rigorous microbiological control systems in breweries.…”

Section: Taxonomy Of Sake and Beer Spoilage Labmentioning

confidence: 99%

“…lindneri, L. paracollinoides and P. damnosus are also frequently encountered species that exhibit strong beer spoilage ability 5,45 . With the exception for P. damnosus that is occasionally found in wineries, these species have been exclusively isolated from beer and related environments 5,45,100,104 , indicating L. lindneri, L. paracollinoides and P. damnosus are brewery-specific microorganisms.…”

Section: Association Of Beer Spoilage Lab With Their Habitatmentioning

confidence: 99%

Sake and Beer Spoilage Lactic Acid Bacteria - A Review

Suzuki

Asano

Iijima

et al. 2008

Self Cite

Japanese rice wine, sake, is a traditional alcoholic beverage in Japan. Similar to the case with beer, sake is known to be microbiologically stable and most microorganisms fail to grow in sake. This is principally due to its high ethanol concentration that reaches approximately 20% (v/v) in undiluted sake products and 15% (v/v) in finished products. Despite the high level of ethanol content, spoilage incidents occasionally occur in sake, due to the presence of highly ethanol-tolerant lactobacilli, known as hiochi-bacteria. Hiochi-bacteria are generally composed of two groups of lactobacilli, hiochi-lactobacilli and true hiochi-bacilli. The former group of lactobacilli is less ethanoland heat-tolerant, and therefore rarely poses a problem to sake products. In contrast, the true hiochi-bacilli exhibit extraordinarily high ethanol tolerance and cause spoilage incidents in sake, conferring acidity and off-flavors, such as diacetyl, in spoiled products. From a taxonomic standpoint, the true hiochi-bacilli mainly consist of two Lactobacillus species, L. fructivorans and L. homohiochi. The strains of true hiochi-bacilli prefer sake-like environments, and the presence of ethanol and mevalonic acid, in combination with low pH milieu, is essential or stimulatory for the growth of these bacteria. Interestingly, the type strain of L. fructivorans does not show such characteristics, suggesting the true hiochi-bacilli are profoundly adapted to sake environments. Although beer spoilage lactic acid bacteria do not have close taxonomic relationships with true hiochi-bacilli, there are striking similarities between these two groups of spoilage lactic acid bacteria. In this review, unique features of sake and beer spoilage lactic acid bacteria are discussed in comparative terms.

“…Among them the most important spoilage organisms are, according to brewing literature, L. brevis, L. lindneri, L. paracollinoides and P. damnosus 2,30,32,34 . In addition, L. backi and P. inopinatus have been reported as potential beer spoilers 7,22,33 . A recently characterised strain, P. clausseni, has been shown to spoil beer 12 .…”

Section: Introductionmentioning

confidence: 99%

“…They exert bacteriostatic effects on most Gram-positive bacteria as they act as proton ionophores and dissipate the transmembrane pH gradient. Several LAB species, such as Lactobacillus spp., have been found to have acquired beer-spoilage ability due to hop resistance genes (horA and horC), and consideration must be given to the fact that altering the hop composition of beer can have a profound impact on the organoleptic and physico-chemical properties of the final product 6,21,22,33,35 .…”

Section: Introductionmentioning

confidence: 99%

Effects of Lysozyme on the Microbiological Stability and Organoleptic Properties of Unpasteurized Beer

Silvetti

Brasca

Lodi

et al. 2010

Lysozyme is an antimicrobial enzyme that could be applied to counteract those bacterial species which, due to their own metabolic activity, possess notable beer spoilage ability and lead to loss of beer quality. Experiments were carried out to assess lysozyme potential to prevent the growth of beer spoilage bacteria, and to verify the effect of lysozyme on the microbiological stability and sensory characteristics of unpasteurized beer. Eight replicates, all from the same lot of Italian beer, were treated with 0 and 100 ppm lysozyme. Microbiological analyses were conducted bimonthly to investigate the presence of spoilage bacteria. Sensory analyses were performed to determine whether there were any significant differences in sensory impressions between beers produced with and without lysozyme. Lysozyme exerted a strong inhibitory action on the lactic acid bacteria (LAB) present in the beer and was very stable throughout the shelf life. Sensory tests revealed no unfavourable influence on beer flavour when using lysozyme. Indeed, the shelf life of beer with added lysozyme proved to be extended. Even as late as 1 month after the expiry date it still met with the panellists' approval. Lysozyme may be regarded as an effective agent for preventing microbiological contamination and prolonging the stability of unpasteurized beer.