Wilhelm Bockelmann

Max Rubner-Institut, Carlsruhe, Baden-Württemberg, Germany

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Publications (41)93.38 Total impact

  • Zeitschrift für Gastroenterologie; 09/2014
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    ABSTRACT: Introduction Non alcoholic fatty liver disease (NAFLD), defined by accumulation of triglycerides in hepatocytes in the absence of alcohol consumption, is associated with obesity. Evidences so far suggest that ethanol produced by gut microbial strains may be implicated in this metabolic disease. Methods In vitro fermentation under anaerobic conditions in medium for colonic bacteria (MCB), supplemented with fructose, was applied for evaluating metabolite profiles of the heterofermentative lactic acid bacteria (htLAB) Weissella confusa and Lactobacillus fermentum in absence or presence of sodium citrate, sodium pyruvate, ribose or xylose. Results and Discussion Results obtained showed that in the absence of electron acceptors (citrate, pyruvate), lactate was the major metabolite of W. confusa and L. fermentum. High amounts of ethanol were produced by W. confusa in MCB supplemented with fructose. In contrast, L. fermentum produced high amounts of mannitol in the same medium. Lactate and acetate were the major metabolites of xylose or ribose fermentation by W. confusa and L. fermentum. Changes of fructose fermentation profiles were observed when citrate or pyruvate was added to the medium: besides lactate, succinate and acetate became the major metabolites of W. confusa and L. fermentum. Co-fermentation of both pentoses with fructose by W. confusa or L. fermentum resulted in decreased amounts of ethanol and increased amounts of lactate and acetate. Our data show that citrate and pyruvate may act as electron acceptors for NAD regeneration in htLAB resulting in decreased amounts of ethanol. Furthermore, fermentation by htLAB of pentoses instead of hexoses increases production of acetate at the expense of ethanol. Conclusion Consumption of natural sources or supplementation of diet with citrate, pyruvate or xylose could reduce production of ethanol by intestinal microbiota and thus may decrease the risk of NAFLD.
    2013 EFFoST Annual Meeting: Bio-based Technologies in the Context of European Food Innovation Systems, Bologna, Italy; 11/2013
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    ABSTRACT: I. Einleitung Nichtalkoholische Fettleber (NAFLD) ist definiert als „Fettanhäufung von Triglyceriden in 5 - 10% des Lebergewichts“ (Neuschwander-Teri & Caldwell, 2003) und mit Zeichen des metabolischen Syndroms assoziiert. Einige Studien legen nahe, dass die Darmmikrobiota, hauptsächlich Ethanol produzierende und Gram-negative Bakterien, für die Entwicklung der NAFLD eine Rolle spielen könnte (Nardone et al., 2004). II. Ziele der Arbeit In dieser Arbeit sollte untersucht werden, ob Elektronenakzeptoren (Natriumcitrat oder Natriumpyruvat) die Metaboliten-Profile ausgewählter Stämme der Darmflora und von Probiotika verändern können und inwieweit sich hierin Bakterien unterscheiden. III. Methodik Bakterielle Fermentationen wurden in Wachstumsmedium unter Sauerstoffausschluss durchgeführt. Metabolitenprofile wurden mittels HPLC analysiert. IV. Ergebnisse • Lactobacillus fermentum produziert große Mengen an Ethanol aus Glukose und an Mannit aus Fruktose. • Weissella confusa (Isolat aus menschlichen Darm) produziert große Mengen an Ethanol aus Monosacchariden (Glukose oder Fruktose). • Bei Zusatz von Natriumcitrat oder Natriumpyruvat zu Wachstumsmedium, änderten sich die Metaboliten-Profile erheblich. • Neben Laktat stellten Succinat und Acetat die Hauptmetaboliten für W. confusa und L. fermentum bei Zusatz von Citrat oder Pyruvat dar. V. Folgerung Supplementierung mit Citrat oder Pyruvat konnte die Produktion von Ethanol durch Stämme der Darmflora reduzieren. Im Fall des L. fermentum führte der Austausch von Glukose gegen Fruktose zur Verringerung der Ethanol Produktion. Mögliche Implikationen für die NAFLD werden diskutiert.
    6. Symposium Funktionelle Lebensmittel 2013; 06/2013
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    ABSTRACT: The fate of 5 different Escherichia coli strains, including 3 Shiga toxin-producing E. coli (STEC) strains, was analyzed during the production and ripening of semihard raw milk cheese. The strains, which were previously isolated from raw milk cheese, were spiked into raw milk before cheese production at 2 different levels (approximately 10(1) and 10(3) cfu/mL, respectively). Two cheese types were produced, which differed in cooking temperatures (40 and 46°C). The cheeses were sampled during manufacture and the 16-wk ripening period. An increase in E. coli counts of approximately 3.5 log(10) cfu/g occurred from raw milk to fresh cheese at d 1, which was attributed to a concentration effect during cheese production and growth of the strains. During ripening over 16 wk, a slow, continuous decrease was observed for all strains. However, significant differences were found between the E. coli strains at the applied spiking levels, whereas the inactivation was similar in the 2 different cheese types. The 2 generic E. coli strains survived at higher counts than did the 3 STEC strains. Nevertheless, only 1 of the 3 STEC strains showed significantly weaker survival at both spiking levels and in both cheese types. Six of 16 cheeses made from raw milk at a low spiking level contained more than 10 cfu/g of STEC at the end of the 16-wk ripening process. After enrichment, STEC were detected in almost all cheeses at both spiking levels. Particularly because of the low infectious dose of highly pathogenic STEC, even low colony counts in raw milk cheese are a matter of concern.
    Journal of Dairy Science 12/2012; 96(2). DOI:10.3168/jds.2012-5865 · 2.55 Impact Factor
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    ABSTRACT: People suffering from non-alcoholic fatty liver disease (NAFLD) show - without any consumption of alcohol - all signs of a typical alcohol-induced fatty liver. So far the elicitor of NAFLD remains unclear. However, alcohol produced by the intestinal microbiota has been discussed to be involved in the development of the disease. In order to take a closer look at this problem, a simple fermentation model was established for evaluating strains intestinal and lactic acid bacteria. So far, we analysed Anaerostipes caccae, Bacteroides thetaiotamicron, Bifidobacterium longum, Escherichia coli, Lactobacillus acidophilus, Lactobacillus fermentum, Lactobacillus plantarum and Lactobacillus reuteri with respect to their metabolic activities. Medium for colonic bacteria (MCB), supplemented with different sugars like glucose, fructose, lactulose, arabinose, ribose and inulin was used under anaerobic conditions.The results obtained generally reflected the anticipated metabolic activities. Lactate was the major metabolite for all lactobacilli strains. High amounts of ethanol were observed in L. fermentum and L. reuteri, grown in MCB supplemented with either glucose or fructose. Lactate and acetate were the major metabolites of B. longum, however succinate and acetate were the major metabolic substances of B. thetaiotamicron. On the other hand, butyrate was only the major metabolite of A. caccae in all tested sugars except inulin. E. coli showed mixed acid fermentation with different amount of ethanol from all tested sugars except inulin. Fermentation of lactulose and inulin, two potential prebiotics, could reduce the production of ethanol by the intestinal bacteria. We now plan to conduct co-fermentation experiments to see, whether combinations of different bacteria will change the overall metabolic profiles in general and the production of ethanol in particular. Key words: lactobacilli, Bacteroides thetaiotamicron, fructose, prebiotic, probiotic, intestinal microbiota
    2 nd Kiel Food Science Symposium, Kiel, Germany; 05/2012
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    ABSTRACT: The aim of this work was to investigate how production and freeze-drying conditions of Bifidobacterium animalis subsp. lactis INL1, a probiotic strain isolated from breast milk, affected its survival and resistance to simulated gastric digestion during storage in food matrices. The determination of the resistance of bifidobacteria to simulated gastric digestion was useful for unveiling differences in cell sensitivity to varying conditions during biomass production, freeze-drying and incorporation of the strain into food products. These findings show that bifidobacteria can become sensitive to technological variables (biomass production, freeze-drying and the food matrix) without this fact being evidenced by plate counts.
    Food Microbiology 05/2012; 30(1):274-80. DOI:10.1016/j.fm.2011.12.004 · 3.37 Impact Factor
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    ABSTRACT: Screening of 175 yeasts in an agar plate co-cultivation assay revealed that five out of 31 species reduced Listeria monocytogenes by 4–5 log units, one exceptionally active Pichia norvegensis reduced Listeria by 7 log units. To test the anti-listerial activity of this Pichia strain on cheese, Tilsit cheese and smeared acid curd cheese (Harzer) were prepared. The Tilsit cheese surface was inoculated with a 3%-NaCl brine containing Brevibacterium linens, Microbacterium gubbeenense, Corynebacterium casei, Staphylococcus equorum, Debaryomyces hansenii, P. norvegensis and L. monocytogenes. Ripening was done at 13 °C and >95% relative humidity. On the Tilsit, but not on the Harzer cheeses, a decrease of listerial cell numbers by 1–2 log units was observed. The difference between high inhibition in agar plate co-cultivation versus cheese is probably due to a decreased expression of the unknown inhibitory substance due to lactate, but not by the low pH.
    International Dairy Journal 02/2011; 21(2-21):83-89. DOI:10.1016/j.idairyj.2010.08.002 · 2.30 Impact Factor
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    ABSTRACT: The objective of the study was to isolate potential probiotic lactobacilli from Kimere, a pearl millet dough prepared in the Mbeere community of Kenya, East Africa, by fermentation for 18-24 hours. Kimere samples, collected from 11 different homesteads in Mbeere, showed average pH values of 3.63±0.29. Counts of presumptive lactobacilli were 8.52±0.02 log10 colony forming units per gram, respectively. 48 presumptive Lactobacillus isolates were characterised and identified by biochemical and molecular methods. Lactobacillus fermentum (46 isolates) was the dominant Lactobacillus species detected. Analysis of strain diversity with pulsed-field gel electrophoresis indicated relatively large biodiversity among L. fermentum isolates. All L. fermentum isolates were able to grow in MRS medium containing 0.3% ox gall. Twelve of them were able to grow in the presence of 3% ox gall, and of these 60% survived incubation at pH 3 in the presence of 2 mg pepsin per ml for three hours.
    Beneficial Microbes 09/2010; 1(3):243-52. DOI:10.3920/BM2010.0019 · 1.50 Impact Factor
  • Wilhelm Bockelmann, Michael Heller, Knut J. Heller
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    ABSTRACT: Amplified ribosomal DNA restriction analysis was used for classification of 90 yeast strains of 32 species of dairy origin. Primers ITS1 and ITS4 yielded PCR products in the range 375bp (Candida lipolytica) to 915bp (Schizosaccharomyces pombe). Species-specific restriction products were liberated by the enzymes Hin6I, HinfI and BsuRI. Some species showed genetic variation, leading to PCR products of different sizes (Debaryomyces hansenii, C. lipolytica, Candida inconspicua, Candida sake). Restriction patterns of three Trichosporon species were similar; a species determination was possible by including Trichosporon reference strains on the gels. Candida krusei, an essential ripening culture of acid curd cheese, could be distinguished from Candida norvegensis and C. inconspicua. C. lipolytica, an important contaminant of smear cheeses, could be classified by the size of the PCR product and restriction patterns. The method provides a fast and reliable tool for identification of dairy yeasts. Size determination of the PCR products gives a narrow range of possible species, while subsequent restriction analysis allows accurate species classification of relevant dairy yeasts.
    International Dairy Journal 10/2008; 18(10):1066-1071. DOI:10.1016/j.idairyj.2008.05.008 · 2.30 Impact Factor
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    ABSTRACT: In this communication, we describe the isolation of a Lactobacillus delbrueckii subsp. bulgaricus 92063 mutant strain named pH-P11, which differed from the parent strain by low proteolytic activity and altered regulation of expression of lacZ in the presence of glucose or lactose. In the presence of lactose, beta-galactosidase activity was approximately twice as high in pH-P11 than in the wild type. pH-P11 exhibited protosymbiosis together with Streptococcus thermophilus. Yoghurt produced with pH-P11 was characterized by low acidity and little post-acidification during storage. The organoleptic properties (absence of bitterness and other off-flavors, weak sourness, and clear yoghurt taste) were those of a typical "yoghurt mild". This mild flavor was achieved at rather high cell counts of lactobacilli even at the end of shelf-life. High cell counts in conjunction with high beta-galactosidase activity make pH-P11 an interesting strain for application in yoghurt especially designed for consumers with lactose malabsorption. In contrast to "yoghurt mild", which is predominantly produced with Lactobacillus acidophilus together with Streptococcus thermophilus, the product obtained by fermentation with pH-P11 and Streptococcus thermophilus concurs with international standards for yoghurt. During frequent sub-culturing, strain pH-P11, which is supposed to differ from the wild type by one or a few so-far-not-characterized mutations, showed sufficient stability for application in industrial production.
    Biotechnology Journal 04/2007; 2(4):469-79. DOI:10.1002/biot.200600225 · 3.71 Impact Factor
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    ABSTRACT: Amplified ribosomal DNA restriction enzyme analysis (ARDRA), pulsed field gel electrophoresis (PFGE) and ribotyping were used to differentiate among 24 strains of Brevibacterium linens, Brevibacterium casei and Brevibacterium epidermidis obtained from type culture collections or isolated from various smear ripened cheeses. ARDRA was applied to the 16S rDNA. B. linens was shown to be a quite heterogenic group with 2 to at least 4 copies of rrn operons per strain with aberrant nucleotide sequences. AccI gave genus specific restriction patterns and was used to separate Brevibacterium from Corynebacterium species. The expected species specificity of TaqI applied to B. linens type culture strains, but not to all strains isolated from cheese. By AvaI restriction, B. casei and B. linens were differentiated from B. epidermidis and the orange pigmented Arthrobacter casei, a new species of coryneform bacteria; by XmnI restriction, B. linens and B. epidermidis were differentiated from B. casei. One of 4 B. linens genotypes could not be distinguished from B. casei by this method. Here, the typical orange B. linens pigments were used for classification, which was confirmed by partial sequencing of the 16S rDNA.
    Systematic and Applied Microbiology 02/2007; 30(1):50-7. DOI:10.1016/j.syapm.2006.02.008 · 3.31 Impact Factor
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    ABSTRACT: To assess which types of siderophores are typically produced by Brevibacterium and how siderophore production and utilization traits are distributed within this genus. During co-cultivation experiments it was found that growth of B. linens Br5 was stimulated by B. linens NIZO B1410 by two orders of magnitude. The stimulation was caused by the production of hydroxamate siderophores by B. linens NIZO B1410 that enabled the siderophore-auxotrophic strain Br5 to grow faster under the applied iron-limited growth conditions. Different patterns of siderophore production and utilization were observed within the genus Brevibacterium. These patterns did not reflect the phylogenetic relations within the group as determined by partial 16S rDNA sequencing. Most Brevibacterium strains were found to utilize hydroxamate siderophores. Brevibacteria can produce and utilize siderophores although certain strains within this genus are siderophore-auxotrophic. It is reported for the first time that brevibacteria produce and utilize siderophores. This knowledge can be utilized to stimulate growth of auxotrophic strains under certain conditions. Enhancing the growth rate of Brevibacterium is of importance for the application of this species, for example, for cheese manufacturing or for industrial production of enzymes or metabolites.
    Journal of Applied Microbiology 10/2006; 101(3):637-46. DOI:10.1111/j.1365-2672.2006.02928.x · 2.39 Impact Factor
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    ABSTRACT: Three Tilsit-type smear-ripened cheeses were manufactured: one was treated with an undefined smear starter mix, the other two were treated with a different defined smear starter mix. The composition of the surface microflora over 8 weeks of ripening was analyzed using Terminal Restriction Fragment Length Polymorphism (T-RFLP) analysis. During the whole period of ripening starter strains were found to be present; additionally, strains apparently acquired from the environment were found. Most of the strains reached a maximum level after 2–4 weeks but were not observed after 8 weeks, except for the Corynebacterium species, which remained as the dominant bacterial genus on the surface of the fully ripened cheese. This study constitutes the first and successful application of an ALFexpress™ automatic sequence analyzer to T-RFLP analysis. It was found to be an excellent tool for rapid and specific culture-independent assessment of population composition and dynamics of a cheese system.
    International Dairy Journal 06/2005; DOI:10.1016/j.idairyj.2004.08.027 · 2.30 Impact Factor
  • W. Bockelmann, K.P. Willems, H. Neve, K.H. Heller
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    ABSTRACT: Data on typical surface microflora of smeared semi-soft, soft and acid curd cheeses and the minimal composition of suitable surface starter cultures are reviewed. Cultures for semi-soft cheeses should contain Debaryomyces hansenii, Staphylococcus equorum, Corynebacterium casei, Microbacterium gubbeenense (or Arthrobacter nicotianae), and Brevibacterium linens. Apart from D. hansenii, soft cheese surface cultures should contain Geotrichum candidum, which is responsible for the typical appearance and aroma development. M. gubbeenense or A. nicotianae and B. linens are essential for soft cheese ripening, but C. casei is not. S. equorum, not regularly found on the surface of commercial soft cheeses, accelerated deacidification and smear development. Cultures for acid curd cheeses, produced from quarg, should contain Kluyveromyces marxianus and Candida krusei. Staphylococci seem to be essential for ripening. S. equorum can replace the non-food-grade S. saprophyticus that is always present on commercial acid curd cheeses. Suitable corynebacteria for spraying of cheeses are B. linens and C. variabile.
    International Dairy Journal 06/2005; 15(6-9-15):719-732. DOI:10.1016/j.idairyj.2004.08.022 · 2.30 Impact Factor
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    ABSTRACT: Young Tilsit cheese is traditionally smeared during ripening using smear liquid from older cheese which facilitates the development of surface flora, but this practice is undesirable from the point of view of hygiene. The objectives of this study were to investigate an alternative to this traditional practice involving a defined-strain surface starter. Two trials of Tilsit cheese were undertaken. In Trial 1, cheese were smeared with a reference smear (R1; old–young smearing) or defined-strain smears, i.e., Mix A (Brevibacterium linens 5 Br5, Microbacterium gubbeenense CA12, Br. casei 047-0399, Corynebacterium casei CA3, Staphylococcus equorum STAPH 2 and Debaryomyces hansenii 6004) or Mix B (as Mix A but C. variabile 025-0165 was used instead of C. casei CA3). In Trial 2, the cheese were smeared with a reference smear (R2) or defined-strain smears, i.e. Mix C (strains as in Mix A except S. equorum STAPH 2 and D. hansenii 6004 were added to the brine) or Mix D (strains as in Mix C plus S. sciuri STAPH 4 and C. variabile 025-0165). Compositional analysis indicated that the surface of the cheese differed from the core due to the action of the smear but that the compositions of the cheese made with the defined strain smear were similar to those made with the reference smears. Levels of pH 4.6-soluble nitrogen, expressed as a percentage of total nitrogen, increased more rapidly at the surface than in the core, reflecting the high level of proteolysis at the higher pH values, but levels were similar in all cheese. Principal component analysis of reverse-phase HPLC chromatograms and data from individual free amino acid analysis separated the surface and core samples of all cheese. Cheese made with the reference smears (R1, R2) were separated from those made with defined strain smear by the end of ripening, reflecting the different proteolytic systems associated with the organisms in the different smears used.
    International Dairy Journal 10/2004; 14(10):871-880. DOI:10.1016/j.idairyj.2004.03.001 · 2.30 Impact Factor
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    ABSTRACT: Amplified Ribosomal-DNA Restriction Analysis (ARDRA) was used to differentiate among 12 species and 4 subspecies of the genus Staphylococcus. With a universal primer pair a 2.4 kbp PCR-product was amplified, including the 16S rDNA, the 16S-23S rDNA interspacer region, and about 500 bp of the 23S rDNA. Species-specific restriction patterns were found using the restriction enzymes HindIII and XmnI separately. Cheese related staphylococci were clearly differentiated. ARDRA results were in good agreement with results of partial sequencing of the 16S rDNA. ARDRA could fully replace the biochemical identification with ID32 Staph (BioMerieux) which was less reliable when staphylococci of cheese origin were analysed. Genomic restriction digests of cheese-related S. equorum strains by SmaI and SacI gave unique strain-specific restriction patterns which can be used to identify starter staphylococci in a complex microbial environment such as the surface of Red-Smear cheeses.
    Systematic and Applied Microbiology 04/2004; 27(2):211-8. DOI:10.1078/072320204322881835 · 3.31 Impact Factor
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    ABSTRACT: ARDRA (Amplified Ribosomal-DNA Restriction Analysis) was used to differentiate among species and genera of Arthrobacter and Microbacteria. Species-specific restriction patterns of PCR-products were obtained with NciI for Arthrobacter citreus (DSM 20133T), A. sulfureus (DSM 20167T), A. globiformis (DSM 20124T) and A. nicotianae strains (DSM 20123T, MGE 10D, CA13, CA14, isolate 95293, 95294, and 95299), A. rhombi CCUG 38813T, and CCUG 38812, and Microbacterium barkeri strains (DSM 30123T, MGE 10D, CA12 and CA15, isolate 95292, and isolate 95207). All yellow pigmented coryneforme bacteria isolated from the smear of surface ripened cheeses were identified as either A. nicotianae or M. barkeri strains. Using pulsed field gel electrophoresis (PFGE) strain specific restriction pattern for all Arthrobacter species and Microbacteria tested were obtained with restriction enzymes AscI and SpeI.
    Systematic and Applied Microbiology 10/2003; 26(3):438-44. DOI:10.1078/072320203322497473 · 3.31 Impact Factor
  • Wilhelm Bockelmann
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    ABSTRACT: For the surface ripened smear cheese varieties it is still general practice to use the mature smear of aged cheeses for the treatment of young cheeses (old–young smearing). The associated hygienic problems are obvious; saprophytic or pathogenic bacteria as well as moulds can become part of the house microflora and can persist over long periods of time by this in-house contamination cycle. This paper summarises studies of the past 8 years aiming to establish defined surface starters for the ripening of Tilsit-type smear cheeses performed in the microbiology department of the Federal Dairy Research Center, Kiel, Germany and currently in a cooperative EU project (FAIR programme, CT98-4220, 1999–2001).Growth on cheese (lab scale) of the five strain minimal starter developed is now comparable to that of a typical old–young smear “starter”. A complete smear layer is developed within 4–7 days. It consists of the yeast Debaryomyces hansenii, and the bacteria Brevibacterium linens, Arthrobacter nicotianae, Corynebacterium ammoniagenes, and Staphylococcus equorum. When defined starters were tested on pilot scale, a too weak sulphury volatile flavour was observed compared to the old–young smeared control cheeses. Some of the key sulphur components (methanethiol and derivatives), some alcohols and aldehydes were produced at lower levels by the defined starters. The development of typical light-brown cheese colour (so-called “red smear”) was attributed to the interactions between yellow-pigmented Arthrobacter spp. and proteolytic bacteria. The orange pigments of B. linens and staphylococci were found to be of lesser importance. The role of Corynebacterium species which show fast growth, is still not clear. An impact of this predominant part of the smear flora on aroma- and colour development can be expected. However, clear effects were not observed in experiments in model systems.
    International Dairy Journal 01/2002; DOI:10.1016/S0958-6946(01)00152-2 · 2.30 Impact Factor
  • Wilhelm Bockelmann, Tobias Hoppe-Seyler
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    ABSTRACT: Debaryomyces hansenii was found to be the predominant yeast in all stages of ripening in several studies on semi-hard Tilsit cheese, soft Chaumes cheese and semi-hard goat's cheese. 75–95% of the bacterial flora was made up of coryneform bacteria. Brevibacterium linens was found at 0–15%. Yellow pigmented coryneform isolates (1–30%) belonged to Arthrobacter nicotianae. Non pathogenic staphylococci (mainly Staphylococcus equorum) were found at 5–15% of the total flora. Model systems were used to study the microbial interactions for growth, colour and aroma development within the surface flora to be able to formulate a defined starter culture.Commercially available surface starters do not reflect the microbial composition of the cheese surface. Too much emphasis is put on B. linens because of the orange pigmentation. New results showed that the red–brown or orange pigments are most likely due to the yellow pigmented Arthrobacter sp. in the surface flora. The mechanisms of developing the different shades of red are not yet understood. B. linens may be more important for aroma development, due to a highly efficient sulfur metabolism which also affects colour development. The importance of commercial S. xylosus is not clear since S. equorum was predominant instead, on all cheese varieties analysed. Brines were determined to be a natural reservoir for salt-tolerant S. equorum. The successful use of a defined 5-strain starter (D. hansenii, B. linens, A. nicotianae, Corynebacterium ammoniagenes and S. sciuri) for Tilsit cheese ripening was demonstrated on a 10 kg scale. Further improvement is currently being tested within an EU funded project.
    International Dairy Journal 07/2001; DOI:10.1016/S0958-6946(01)00060-7 · 2.30 Impact Factor
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    ABSTRACT: Sporulation of Penicillium camemberti was studied in submerged batch fermentation. A defined medium was used with glucose and ammonium as C- and N-sources. Temperature was set to 25 degrees C at pH 5.6. Essential for submerged sporulation was the presence of calcium (14 mM) which was adsorbed to the cell walls in all sporulating strains and inhibited mycelial growth. Acetate led to highly branched conidiophores and was the second main factor for efficient sporulation. The chelating properties of citrate were necessary for keeping calcium and phosphate in solution. Fermentation conditions allowed high spore yields after 96 h (1.6 x 10(8) spores/ml). Cyclopiazonic acid, the mycotoxin common for P. camemberti was produced during fermentation. The levels observed (0.5-4 ppm at 96 h) were strain specific and not related to spore yield.
    Systematic and Applied Microbiology 10/1999; 22(3):479-85. DOI:10.1016/S0723-2020(99)80058-7 · 3.31 Impact Factor

Publication Stats

940 Citations
93.38 Total Impact Points


  • 2011–2012
    • Max Rubner-Institut
      Carlsruhe, Baden-Württemberg, Germany
  • 2007–2010
    • Federal Agency for Agriculture and Food (Germany)
      Berlín, Berlin, Germany
  • 1991
    • Eawag: Das Wasserforschungs-Institut des ETH-Bereichs
      Duebendorf, Zurich, Switzerland