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Peter Vandamme - One of the best experts on this subject based on the ideXlab platform.
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Application of matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) as a fast identification tool for beer Spoilage Bacteria
2020Co-Authors: Anneleen Wieme, Anita Van Landschoot, Peter VandammeAbstract:Beer Spoilage induced by Bacteria is a common problem in the brewing industry and has a great impact on the brewing economy. The present study aims to develop a quick, accurate and inexpensive method to detect and identify beer Spoilage Bacteria. To achieve this, an extensive database comprising about 6500 MALDI-TOF MS-profiles including more than 260 accurately identified contaminants and beer Spoilage isolates was built. The 260 isolates represent all commonly encountered Spoilage Bacteria with a focus on lactobacilli, acetic acid Bacteria and some anaerobes. The profiles revealed culture-independent species-specific biomarker peaks for all Spoilage species, allowing straightforward identification of novel isolates. The final aim of the present study is to detect and identify Spoilage Bacteria in a sample with no or minimal culture steps.
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Exploration of matrix-assisted laser desorption ionization-time of flight mass spectrometry as a fast identification tool for beer Spoilage Bacteria
2020Co-Authors: Anneleen Wieme, Anita Van Landschoot, Peter VandammeAbstract:Beer is a beverage with good microbiological stability because it contains almost no oxygen and nutrients for the growth of many Bacteria. In addition, low pH, high CO2-content and the presence of ethanol and antiBacterial hop compounds ensure microbial stability. Nevertheless, beer Spoilage induced by Bacteria is a common problem in the brewing industry and these Spoilage Bacteria typically cause visible turbidity, acidity and off-flavours. In modern breweries the hop-resistant, Gram positive, lactic acid Bacteria Lactobacillus brevis, Lb. lindneri, Lb. brevisimilis, Lb. coryneformis, Lb. plantarum, Lb. malefermentans, Lb. parabuchneri, Pediococcus damnosus, P. inopinatus and P. dextrinicus are generally regarded as the most hazardous beer Spoilage Bacteria. Recently, the process technology improved and therefore the importance of aerobic acetic acid Bacteria, genera such as Acetobacter and Gluconobacter, has decreased. In contrast, the appearance of strictly anaerobic Gram negative Bacteria, like Pectinatus cerevisiiphilus, P. frisingensis, Selenomonas lacticifex, Megasphaera cerevisiae and Zymophilus raffinosivorans, has increased.
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identification of beer Spoilage Bacteria using matrix assisted laser desorption ionization time of flight mass spectrometry
International Journal of Food Microbiology, 2014Co-Authors: Anneleen Wieme, Anita Van Landschoot, Freek Spitaels, Maarten Aerts, Katrien De Bruyne, Peter VandammeAbstract:Abstract Applicability of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for identification of beer-Spoilage Bacteria was examined. To achieve this, an extensive identification database was constructed comprising more than 4200 mass spectra, including biological and technical replicates derived from 273 acetic acid Bacteria (AAB) and lactic acid Bacteria (LAB), covering a total of 52 species, grown on at least three growth media. Sequence analysis of protein coding genes was used to verify aberrant MALDI-TOF MS identification results and confirmed the earlier misidentification of 34 AAB and LAB strains. In total, 348 isolates were collected from culture media inoculated with 14 spoiled beer and brewery samples. Peak-based numerical analysis of MALDI-TOF MS spectra allowed a straightforward species identification of 327 (94.0%) isolates. The remaining isolates clustered separately and were assigned through sequence analysis of protein coding genes either to species not known as beer-Spoilage Bacteria, and thus not present in the database, or to novel AAB species. An alternative, classifier-based approach for the identification of Spoilage Bacteria was evaluated by combining the identification results obtained through peak-based cluster analysis and sequence analysis of protein coding genes as a standard. In total, 263 out of 348 isolates (75.6%) were correctly identified at species level and 24 isolates (6.9%) were misidentified. In addition, the identification results of 50 isolates (14.4%) were considered unreliable, and 11 isolates (3.2%) could not be identified. The present study demonstrated that MALDI-TOF MS is well-suited for the rapid, high-throughput and accurate identification of Bacteria isolated from spoiled beer and brewery samples, which makes the technique appropriate for routine microbial quality control in the brewing industry.
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Identification of beer-Spoilage Bacteria using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.
International Journal of Food Microbiology, 2014Co-Authors: Anneleen Wieme, Anita Van Landschoot, Freek Spitaels, Maarten Aerts, Katrien De Bruyne, Peter VandammeAbstract:Abstract Applicability of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for identification of beer-Spoilage Bacteria was examined. To achieve this, an extensive identification database was constructed comprising more than 4200 mass spectra, including biological and technical replicates derived from 273 acetic acid Bacteria (AAB) and lactic acid Bacteria (LAB), covering a total of 52 species, grown on at least three growth media. Sequence analysis of protein coding genes was used to verify aberrant MALDI-TOF MS identification results and confirmed the earlier misidentification of 34 AAB and LAB strains. In total, 348 isolates were collected from culture media inoculated with 14 spoiled beer and brewery samples. Peak-based numerical analysis of MALDI-TOF MS spectra allowed a straightforward species identification of 327 (94.0%) isolates. The remaining isolates clustered separately and were assigned through sequence analysis of protein coding genes either to species not known as beer-Spoilage Bacteria, and thus not present in the database, or to novel AAB species. An alternative, classifier-based approach for the identification of Spoilage Bacteria was evaluated by combining the identification results obtained through peak-based cluster analysis and sequence analysis of protein coding genes as a standard. In total, 263 out of 348 isolates (75.6%) were correctly identified at species level and 24 isolates (6.9%) were misidentified. In addition, the identification results of 50 isolates (14.4%) were considered unreliable, and 11 isolates (3.2%) could not be identified. The present study demonstrated that MALDI-TOF MS is well-suited for the rapid, high-throughput and accurate identification of Bacteria isolated from spoiled beer and brewery samples, which makes the technique appropriate for routine microbial quality control in the brewing industry.
Kyu-seok Jung - One of the best experts on this subject based on the ideXlab platform.
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Growth characteristics and biofilm formation of various Spoilage Bacteria isolated from fresh produce.
Journal of Food Science, 2014Co-Authors: Ling Zheng, Jeong-eun Hyun, Kyu-seok JungAbstract:UNLABELLED: This study investigated the characteristics of Spoilage Bacteria isolated from fresh produce including growth at various temperatures, biofilm formation, cell hydrophobicity, and colony spreading. The number of Spoilage Bacteria present when stored at 35 °C was significantly greater than when stored at lower temperatures, and maximum population size was achieved after 10 h. However, Bacillus pumilus, Dickeya zeae, Pectobacterium carotovorum subsp. Carotovorum Pcc21, and Bacillus pumilus (RDA-R) did not grow at the storage temperature of 5 °C. The biofilm formation by Clavibacter michiganensis, Acinetobacter calcoaceticus, and A. calcoaceticus (RDA-R) are higher than other Spoilage Bacteria. Biofilm formation showed low correlation between hydrophobicity, and no significant correlation with colony spreading. These results might be used for developing safe storage guidelines for fresh produce at various storage temperatures, and could be basic information on the growth characteristics and biofilm formation properties of Spoilage Bacteria from fresh produce. PRACTICAL APPLICATION: Growth of Spoilage Bacteria was different depending on the Bacteria strains and storage temperature. Between biofilm formation and cell hydrophobicity was low correlation on Spoilage Bacteria. Therefore, growth characteristics and biofilm formation of Spoilage Bacteria might be used for developing safe storage guidelines for fresh produce at various storage temperatures.
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antimicrobial activity of natural antimicrobial substances against Spoilage Bacteria isolated from fresh produce
Food Control, 2013Co-Authors: Ling Zheng, Kyu-seok JungAbstract:Abstract The aim of this study was to investigate the efficacy of natural antimicrobial substances for inhibiting vegetable Spoilage Bacteria. Natural antimicrobial compounds (carvacrol, thymol, eugenol, cinnamic acid, nisin, and chitosan), organic acids (acetic acid and lactic acid), and chemical sanitizers (sodium hypochlorite and chlorine dioxide) were evaluated for their antiBacterial activities, as single and combination treatments, against 15 Spoilage Bacteria isolated from vegetables, using the agar disc diffusion and broth dilution methods. Carvacrol, thymol, and eugenol showed strong inhibitory effects compared to those of the other antimicrobial substances, and their average minimum inhibitory concentration (MIC) values against 15 Spoilage Bacteria were 167, 648, and 168 μg/ml, respectively. When they were combined, four kinds (carvacrol + thymol, carvacrol + eugenol, thymol + eugenol, and carvarol + thymol + eugenol) of the combination formulas showed higher antiBacterial effect than others against Spoilage Bacteria, with average MIC values of 47, 43, 59, and 42 μg/ml, respectively. However, two combinations (carvacrol + thymol, and carvacrol + thymol + eugenol) showed the strongest inhibitory effects against Bacteria in fresh vegetables among all treatments. These results could be used for the development of new sanitation or preservation methods to improve freshness and to extend the shelf-life of fresh produce.
Wil N Konings - One of the best experts on this subject based on the ideXlab platform.
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beer Spoilage Bacteria and hop resistance
International Journal of Food Microbiology, 2003Co-Authors: Kanta Sakamoto, Wil N KoningsAbstract:Abstract For brewing industry, beer Spoilage Bacteria have been problematic for centuries. They include some lactic acid Bacteria such as Lactobacillus brevis, Lactobacillus lindneri and Pediococcus damnosus, and some Gram-negative Bacteria such as Pectinatus cerevisiiphilus, Pectinatus frisingensis and Megasphaera cerevisiae. They can spoil beer by turbidity, acidity and the production of unfavorable smell such as diacetyl or hydrogen sulfide. For the microbiological control, many advanced biotechnological techniques such as immunoassay and polymerase chain reaction (PCR) have been applied in place of the conventional and time-consuming method of incubation on culture media. Subsequently, a method is needed to determine whether the detected bacterium is capable of growing in beer or not. In lactic acid Bacteria, hop resistance is crucial for their ability to grow in beer. Hop compounds, mainly iso-α-acids in beer, have antiBacterial activity against Gram-positive Bacteria. They act as ionophores which dissipate the pH gradient across the cytoplasmic membrane and reduce the proton motive force (pmf). Consequently, the pmf-dependent nutrient uptake is hampered, resulting in cell death. The hop-resistance mechanisms in lactic acid Bacteria have been investigated. HorA was found to excrete hop compounds in an ATP-dependent manner from the cell membrane to outer medium. Additionally, increased proton pumping by the membrane bound H+-ATPase contributes to hop resistance. To energize such ATP-dependent transporters hop-resistant cells contain larger ATP pools than hop-sensitive cells. Furthermore, a pmf-dependent hop transporter was recently presented. Understanding the hop-resistance mechanisms has enabled the development of rapid methods to discriminate beer Spoilage strains from nonspoilers. The horA-PCR method has been applied for Bacterial control in breweries. Also, a discrimination method was developed based on ATP pool measurement in lactobacillus cells. However, some potential hop-resistant strains cannot grow in beer unless they have first been exposed to subinhibitory concentration of hop compounds. The beer Spoilage ability of Pectinatus spp. and M. cerevisiae has been poorly studied. Since all the strains have been reported to be capable of beer spoiling, species identification is sufficient for the breweries. However, with the current trend of beer flavor (lower alcohol and bitterness), there is the potential risk that not yet reported Bacteria will contribute to beer Spoilage. Investigation of the beer Spoilage ability of especially Gram-negative Bacteria may be useful to reduce this risk.
Anneleen Wieme - One of the best experts on this subject based on the ideXlab platform.
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Application of matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) as a fast identification tool for beer Spoilage Bacteria
2020Co-Authors: Anneleen Wieme, Anita Van Landschoot, Peter VandammeAbstract:Beer Spoilage induced by Bacteria is a common problem in the brewing industry and has a great impact on the brewing economy. The present study aims to develop a quick, accurate and inexpensive method to detect and identify beer Spoilage Bacteria. To achieve this, an extensive database comprising about 6500 MALDI-TOF MS-profiles including more than 260 accurately identified contaminants and beer Spoilage isolates was built. The 260 isolates represent all commonly encountered Spoilage Bacteria with a focus on lactobacilli, acetic acid Bacteria and some anaerobes. The profiles revealed culture-independent species-specific biomarker peaks for all Spoilage species, allowing straightforward identification of novel isolates. The final aim of the present study is to detect and identify Spoilage Bacteria in a sample with no or minimal culture steps.
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Exploration of matrix-assisted laser desorption ionization-time of flight mass spectrometry as a fast identification tool for beer Spoilage Bacteria
2020Co-Authors: Anneleen Wieme, Anita Van Landschoot, Peter VandammeAbstract:Beer is a beverage with good microbiological stability because it contains almost no oxygen and nutrients for the growth of many Bacteria. In addition, low pH, high CO2-content and the presence of ethanol and antiBacterial hop compounds ensure microbial stability. Nevertheless, beer Spoilage induced by Bacteria is a common problem in the brewing industry and these Spoilage Bacteria typically cause visible turbidity, acidity and off-flavours. In modern breweries the hop-resistant, Gram positive, lactic acid Bacteria Lactobacillus brevis, Lb. lindneri, Lb. brevisimilis, Lb. coryneformis, Lb. plantarum, Lb. malefermentans, Lb. parabuchneri, Pediococcus damnosus, P. inopinatus and P. dextrinicus are generally regarded as the most hazardous beer Spoilage Bacteria. Recently, the process technology improved and therefore the importance of aerobic acetic acid Bacteria, genera such as Acetobacter and Gluconobacter, has decreased. In contrast, the appearance of strictly anaerobic Gram negative Bacteria, like Pectinatus cerevisiiphilus, P. frisingensis, Selenomonas lacticifex, Megasphaera cerevisiae and Zymophilus raffinosivorans, has increased.
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identification of beer Spoilage Bacteria using matrix assisted laser desorption ionization time of flight mass spectrometry
International Journal of Food Microbiology, 2014Co-Authors: Anneleen Wieme, Anita Van Landschoot, Freek Spitaels, Maarten Aerts, Katrien De Bruyne, Peter VandammeAbstract:Abstract Applicability of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for identification of beer-Spoilage Bacteria was examined. To achieve this, an extensive identification database was constructed comprising more than 4200 mass spectra, including biological and technical replicates derived from 273 acetic acid Bacteria (AAB) and lactic acid Bacteria (LAB), covering a total of 52 species, grown on at least three growth media. Sequence analysis of protein coding genes was used to verify aberrant MALDI-TOF MS identification results and confirmed the earlier misidentification of 34 AAB and LAB strains. In total, 348 isolates were collected from culture media inoculated with 14 spoiled beer and brewery samples. Peak-based numerical analysis of MALDI-TOF MS spectra allowed a straightforward species identification of 327 (94.0%) isolates. The remaining isolates clustered separately and were assigned through sequence analysis of protein coding genes either to species not known as beer-Spoilage Bacteria, and thus not present in the database, or to novel AAB species. An alternative, classifier-based approach for the identification of Spoilage Bacteria was evaluated by combining the identification results obtained through peak-based cluster analysis and sequence analysis of protein coding genes as a standard. In total, 263 out of 348 isolates (75.6%) were correctly identified at species level and 24 isolates (6.9%) were misidentified. In addition, the identification results of 50 isolates (14.4%) were considered unreliable, and 11 isolates (3.2%) could not be identified. The present study demonstrated that MALDI-TOF MS is well-suited for the rapid, high-throughput and accurate identification of Bacteria isolated from spoiled beer and brewery samples, which makes the technique appropriate for routine microbial quality control in the brewing industry.
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Identification of beer-Spoilage Bacteria using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.
International Journal of Food Microbiology, 2014Co-Authors: Anneleen Wieme, Anita Van Landschoot, Freek Spitaels, Maarten Aerts, Katrien De Bruyne, Peter VandammeAbstract:Abstract Applicability of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for identification of beer-Spoilage Bacteria was examined. To achieve this, an extensive identification database was constructed comprising more than 4200 mass spectra, including biological and technical replicates derived from 273 acetic acid Bacteria (AAB) and lactic acid Bacteria (LAB), covering a total of 52 species, grown on at least three growth media. Sequence analysis of protein coding genes was used to verify aberrant MALDI-TOF MS identification results and confirmed the earlier misidentification of 34 AAB and LAB strains. In total, 348 isolates were collected from culture media inoculated with 14 spoiled beer and brewery samples. Peak-based numerical analysis of MALDI-TOF MS spectra allowed a straightforward species identification of 327 (94.0%) isolates. The remaining isolates clustered separately and were assigned through sequence analysis of protein coding genes either to species not known as beer-Spoilage Bacteria, and thus not present in the database, or to novel AAB species. An alternative, classifier-based approach for the identification of Spoilage Bacteria was evaluated by combining the identification results obtained through peak-based cluster analysis and sequence analysis of protein coding genes as a standard. In total, 263 out of 348 isolates (75.6%) were correctly identified at species level and 24 isolates (6.9%) were misidentified. In addition, the identification results of 50 isolates (14.4%) were considered unreliable, and 11 isolates (3.2%) could not be identified. The present study demonstrated that MALDI-TOF MS is well-suited for the rapid, high-throughput and accurate identification of Bacteria isolated from spoiled beer and brewery samples, which makes the technique appropriate for routine microbial quality control in the brewing industry.
Ling Zheng - One of the best experts on this subject based on the ideXlab platform.
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Growth characteristics and biofilm formation of various Spoilage Bacteria isolated from fresh produce.
Journal of Food Science, 2014Co-Authors: Ling Zheng, Jeong-eun Hyun, Kyu-seok JungAbstract:UNLABELLED: This study investigated the characteristics of Spoilage Bacteria isolated from fresh produce including growth at various temperatures, biofilm formation, cell hydrophobicity, and colony spreading. The number of Spoilage Bacteria present when stored at 35 °C was significantly greater than when stored at lower temperatures, and maximum population size was achieved after 10 h. However, Bacillus pumilus, Dickeya zeae, Pectobacterium carotovorum subsp. Carotovorum Pcc21, and Bacillus pumilus (RDA-R) did not grow at the storage temperature of 5 °C. The biofilm formation by Clavibacter michiganensis, Acinetobacter calcoaceticus, and A. calcoaceticus (RDA-R) are higher than other Spoilage Bacteria. Biofilm formation showed low correlation between hydrophobicity, and no significant correlation with colony spreading. These results might be used for developing safe storage guidelines for fresh produce at various storage temperatures, and could be basic information on the growth characteristics and biofilm formation properties of Spoilage Bacteria from fresh produce. PRACTICAL APPLICATION: Growth of Spoilage Bacteria was different depending on the Bacteria strains and storage temperature. Between biofilm formation and cell hydrophobicity was low correlation on Spoilage Bacteria. Therefore, growth characteristics and biofilm formation of Spoilage Bacteria might be used for developing safe storage guidelines for fresh produce at various storage temperatures.
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antimicrobial activity of natural antimicrobial substances against Spoilage Bacteria isolated from fresh produce
Food Control, 2013Co-Authors: Ling Zheng, Kyu-seok JungAbstract:Abstract The aim of this study was to investigate the efficacy of natural antimicrobial substances for inhibiting vegetable Spoilage Bacteria. Natural antimicrobial compounds (carvacrol, thymol, eugenol, cinnamic acid, nisin, and chitosan), organic acids (acetic acid and lactic acid), and chemical sanitizers (sodium hypochlorite and chlorine dioxide) were evaluated for their antiBacterial activities, as single and combination treatments, against 15 Spoilage Bacteria isolated from vegetables, using the agar disc diffusion and broth dilution methods. Carvacrol, thymol, and eugenol showed strong inhibitory effects compared to those of the other antimicrobial substances, and their average minimum inhibitory concentration (MIC) values against 15 Spoilage Bacteria were 167, 648, and 168 μg/ml, respectively. When they were combined, four kinds (carvacrol + thymol, carvacrol + eugenol, thymol + eugenol, and carvarol + thymol + eugenol) of the combination formulas showed higher antiBacterial effect than others against Spoilage Bacteria, with average MIC values of 47, 43, 59, and 42 μg/ml, respectively. However, two combinations (carvacrol + thymol, and carvacrol + thymol + eugenol) showed the strongest inhibitory effects against Bacteria in fresh vegetables among all treatments. These results could be used for the development of new sanitation or preservation methods to improve freshness and to extend the shelf-life of fresh produce.