Acetic acid bacteria (AAB) are often considered a threat of the past because today’s equipment allows to perform post-fermentation processes under greatly reduced level of oxygen. This paper deals with the current importance of AAB in brewing. The risk of contamination as well as functional role in spontaneously fermented sour beers is reviewed. The main harmful effect of AAB lies in the direct spoilage of draft beer and formation of biofilms, most often in dispensing systems. On contrary AAB seems to be indispensable in the case of sour beer production. A key issue of AAB in brewing environment is their (early) detection and identification. Therefore, part of this study is devoted to both the latest sophisticated methods and also those of traditional cultivation. which are still prevalent in operating laboratories due to their cost and easy implementation. Finally, the experimental and pictorial material is added as a guide for operations that have less experience with AAB.

Bacteria of the genus Bacillus are often detected in brewing operations, but they rank among less hazardous contaminants. They are not able to survive in the vegetative form in beer and spoil it. Spores of Bacillus bacteria are present especially in malt and grain adjuncts. They are able to survive wort boiling, however in the following phases they are not able to germinate because of their sensitivity to bitter hop substances and low pH of fermenting wort and fi nished beer. We provide here an overview of basic morphological and physiological properties of these bacteria and describe their importance in brewing process. Particular attention is given to species B. cereus and B. licheniformis for which has been proved the presence of the horA gene, which is associated with resistence of lactic acid bacteria to hop substances. Species Brevibacillus brevis and Paenibacillus macerans, which were previously included in the genus Bacillus, are also described.Brožová, M., Kubizniaková, P., Matoulková, D., 2018: Mikrobiologie pivovarské výroby -bakterie rodů Bacillus, Brevibacillus a Paenibacillus a kultivační metody pro jejich detekci -1. část. Kvasny Prum., 64(2): 50-57Bakterie rodu Bacillus jsou v pivovarských provozech často detekovány, řadí se však mezi méně rizikové kontaminanty. Ve vegetativní formě nejsou schopné přežívat v pivu a nekazí ho. Spory bakterií Bacillus jsou přítomny zejména ve sladu a obilných náhražkách sladu, přežijí chmelovar, ale v navazujících fázích výroby piva nevyklíčí -jsou citlivé na hořké chmelové látky a nízké pH kvasící mladiny a hotového piva. V publikaci jsou popsány základní morfologické a fysiologické vlastnosti těchto bakterií, je zde popsán jejich význam v procesu výroby piva. Zvláštní pozornost je věnována druhům B. cereus a B. licheniformis, u kterých byla prokázána přítomnost genu horA, který je spojován s rezistencí bakterií mléčného kvašení k chmelovým látkám. Publikace se dále věnuje druhům Brevibacillus brevis a Paenibacillus macerans, které byly dříve řazeny do rodu Bacillus. (meat, vegetables, milk, cereals). Due to their frequent occurrence in nature and thermoresistant spores, they enter the brewing operation mostly with raw materials (water, malt, hop). Bacillus bacteria are able to survive mashing and wort boiling, therefore they can also be found in fi nished beer (Back, 2005;Vaughan et al., 2005). However, in most species their following growth in beer is inhibited by bitter hop products and acid pH (Back, 2005;Basařová et al., 2010). Generally, they are not considered hazardous brewing contaminants, due to their inability to grow in beer, nor after adaptation to outer conditions, and the fact that they do not affect biological stability of fi nished beer. Undesirable is the ability of some bacilli to reduce nitrates to nitrites that may cause the formation of N-nitrosamines in beer (Back, 2005;Bokulich and Bamforth, 2013;Briggs et al., 2004). Keywords ■ 2 GENERAL CHARACTERISTICS OF GENUS BACILLUSBacteria of the genus Bacillus are aerobic or facultative anaerobic,...

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bacteria of the order Enterobacterales. Kvasny Prum. 64(4): 161-166 The Enterobacterales order contains 7 families with more than 40 bacterial genera which are isolated from various types of environment. The genera Shimwellia, Obesumbacterium, Rahnella, Citrobacter, Klebsiella, Raoultella, Serratia and Enterobacter are often found in the beer brewing process. The ability of these bacteria to grow and multiply in the finished beer is minimal. The bacteria occur primarily as contamination of yeast. They are harmful because these bacteria produce sensory undesirable substances (e.g. dimethylsulfide, diacetyl, acetoin) at the beginning of the main fermentation and get into the finished beer. Some species are involved in the formation of N-nitrosamines harmful for health. Here we present an overview of the basic morphological and physiological properties of these bacteria and describe their importance from the point of view of harmfulness in the beer brewing process.

The growth of 7 strains belonging to the order of Enterobacterales, represented by the species of Citrobacter Freundii, Enterobacter cloacae, Escherichia coli, Klebsiella oxytoca, Obesumbacterium proteus, Rahnella aquatilis, Raoultella terrigena, Serratia marcescens and Shimwellia pseudoproteus, was monitored on selected cultivation media. Three types of agars - Endo, MacConkey and Chromocult Coliform agar together with two incubation temperatures of 28 and 37 °C were tested under aerobic conditions. The aim of the study was to detect such essential enterobacteria harmful to beer that cannot be proven at 37 °C, which is the temperature usually used in operational laboratories in breweries. Our results showed that most of the tested strains of enterobacteria were able to grow at 28 °C on all selected types of agar. The exception was just the representatives detection of which is problematic at 37 °C. Nevertheless, a little or no growth was always observed on just one of the tested media.

In most cases, the Clostridium species rank among the sporogenic obligate anaerobes, which are sensitive to bitter hop substances and acidic pH. Thus they rank among the less dangerous contaminants in brewing operations. Their increased incidence in breweries can be linked to the modernization of technologies, which reduces access to oxygen in individual production phases. The endospores of Clostridium bacteria were isolated, e.g., from the storage vessels for liquid malt substitutes (glucose, starch syrups). They are able to survive the conditions of mashing and wort boiling, but they can not germinate in the following phases of beer production. However, their ability to be present in the vegetative form until the wort preparation presents a risk of damage to finished beer-vegetative cells form a number of undesirable organic acids, which may pass into the finished product. We provide here an overview of basic morphological and physiological properties of these bacteria and describe their importance in the brewing process. Particular attention is given to species Clostridium acetobutylicum, C. butyricum, C. cellulovorans, C. pasteurianum, C. thermocellum, "C. thermosaccharolyticum" (Thermoanaerobacterium thermosaccharolyticum) and C. tyrobutyricum, which were detected in brewing operations.

The role of the cytochrome P450 1A2 (CYP1A2) rs2472299, rs2470890 and rs11072508 polymorphisms in prostate cancer risk, disease progression and tumour development remains unclear. The potential associations of these three CYP1A2 polymorphisms and haplotypes with prostate cancer susceptibility and its clinicopathological characteristics were therefore investigated. The present case-control study consisted of 522 patients with prostate cancer and 554 healthy controls. High-resolution melting analysis was used to determine the CYP1A2 polymorphisms. No significant association in prostate cancer risk was seen for CYP1A2 rs2472299 and rs11072508. However, a significantly decreased risk of prostate cancer was found for CYP1A2 rs2470890 [odds ratio (OR), 0.67; P=0.02] in the recessive model. After analysis of the associations of clinical status and these three CYP1A2 polymorphisms, the CYP1A2 rs2470890 and rs11072508 polymorphisms showed a positive association with a higher Gleason score (rs2470890 OR, 1.36, P=0.04 in the allelic model; rs11072508 OR, 1.37, P=0.04 in the allelic model and OR, 1.60, P=0.03 in the dominant model). All three polymorphisms showed a significant positive association with pathological T stage in the additive, allelic and dominant genetic models (P<0.05). Haplotype analysis revealed that the most common haplotypes 'GTT' and 'ACC' were significantly associated with pathological T stages 3 and 4 (OR, 0.62; P=0.02 and OR, 1.54; P=0.03, respectively). A significant association was found between the 'GTT' haplotype and the Gleason score (OR, 0.71; P=0.03). In conclusion, these CYP1A2 polymorphisms and haplotypes have the potential to predict prostate cancer disease progression.

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