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Zentralinstitut für Ernährungs- und Lebensmittelforschung (ZIEL)

Abteilung Mikrobiologie
Technische Universität München
Weihenstephaner Berg 3
D-85350 Freising


Hygiene and microbiota of milk products 

Group leader:   Dr. Etienne Doll

Anna Dettling, MSc, PhD Student
Angela Felsl, Technician
Patrick Schiwek, Technician
Annemarie Siebert, MSc, PhD Student
Dr. Lena Staib, Postdoc

This project is performed in close cooperation with Dr. Mareike Wenning, LGL Oberschleißheim (https://www.lgl.bayern.de)


The group’s focus is on the applied research of the hygiene and microbiota of milk and milk products. The value chain of dairy products strongly depends on their hygienic properties. The main determinants of an impeccable microbial quality are the raw milk microbiota on the one hand, and the hygienic design of production processes on the other hand.

In the NextMilQ project, we analyze the raw milk microbiota by high-throughput amplicon sequencing. Apart from a “typical” qualitative and quantitative composition of the microbiota, we aim to analyze different influencing factors like conventional or organic production, geographic position, and herd size. Additionally, methods for the rapid detection of hygienically relevant (spoilage) microorganisms are developed.

The second project’s focus is on the process hygiene in the production of milk and whey powders. Here, counts of thermophilic spores are important indicators and determinants of product quality. To reduce the spore-load of powders we investigate strategies to avoid and reduce the persistence of thermophilic strains in the processing lines. Therefore, persisting strains are detected by RAPD-typing and the inactivation-efficacy of different cleaning regimens is tested experimentally. Additionally, the adaptation of strains on a genetic level is analyzed by comparative genomics.

Publications

Wedel C, Wunsch A, Wenning M, Dettling A, Kayser K-H, Lehner W-D, Hinrichs J (2018) Thermal treatment of skim milk concentrates in a novel shear-heating device: Reduction of thermophilic spores and physical properties. Food Res Int. 2018 May; 107:19-26.

Reich C, Wenning M, Dettling A, Luma KE, Hinrichs J (2017) Thermal resistance of vegetative thermophilic spore forming bacilli in skim milk isolated from dairy environments. Food Control. 2017 Dec; 82:114-120.

Doll EV, Scherer S, Wenning M (2017) Spoilage of microfiltered and pasteurized Extended Shelf Life Milk is mainly induced by psychrotolerant spore-forming bacteria that often originate from recontamination. Front Microbiol. 2017 Jan 31; 8: 135.

von Neubeck M, Baur C, Krewinkel M, Stoeckel M, Kranz B, Stressler T, Fischer L, Hinrichs J, Scherer S, Wenning M (2015) Biodiversity of refrigerated raw milk microbiota and their enzymatic spoilage potential. Int. J Food Microbiol.2015 Oct 15; 211: 57-65.

Wenning M, Scherer S (2013) Identification of microorganisms by FTIR spectroscopy: perspectives and limitations of the method. Appl Microbiol Biotechnol. 2013 Jul 17; 97:7111-712.

Schmidt VSJ, Kaufmann V, Kulozik U, Scherer S, Wenning M (2012) Microbial biodiversity, quality, and shelf life of microfiltered and pasteurized extended shelf life (ESL) milk from Germany, Austria, and Switzerland. Int J Food Microbiol. 2012 Mar; 154:1-9.

Wenning M, Theilmann V, Scherer S. (2006) Rapid analysis of two food-borne microbial communities at the species level by Fourier-transform infrared microspectroscopy. Environ. Microbiol. 2006 Apr 04; 8:848-857.

 



News

Paper
Optimality in the standard gentic code is robust with respect to comparison code sets (2019)

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Accurate quantification of thermophilic spores in dairy powders (2019)

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Pseudomonas lactis sp. nov. and Pseudomonas paralactis sp. nov., isolated from bovine raw milk (2017)

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Resistance of thermophilic spore formers isolated from milk and whey products towards cleaning-in-place conditions: Influence of pH, temperature and milk residues (2019)

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Proposal of Lysobacter pythonis sp. nov. isolated from royal pythons (Python regius) (2019)

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The novel EHEC gene asa overlaps the TEGT transporter gene in antisense and is regulated by NaCl and growth Phase (Dec 2018)

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The small RNA RssR regulates myo-inositol degradation by Salmonella enterica (Dec.2018)

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Activity of a Holin-Endolysin System in the Insecticidal Pathogenicity Island of Yersinia enterocolitica (2018)

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Reprogramming Human Siderocalin to Neutralize Petrobactin, the Essential Iron Scavenger of Anthrax Bacillus (2018)

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Insecticidal Toxicity of Yersinia frederiksenii Involves the Novel Enterotoxin YacT (2018)

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Dysfunction, Disease, and the Limits of Selection (2018)

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Dynamic Proteome Alteration and Functional Modulation of Human Saliva Induced by Dietary Chemosensory Stimuli (2018)

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Genome sequence of the novel virulent bacteriophage PMBT14 with lytic avtivity against Pseudomonas fluorescens DSM 50090 (2018)

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The Novel Anaerobiosis-Responsive Overlapping Antisense to the Annotated Gene ECs2385 of Escherichia coli O157:H7 Sakai (Mai 2018)

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Thermal treatment of skim milk concentrates in a novel shear-heating device: Reduction of thermophilic spores and physical properties (Febr. 2018)

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A novel short L-arginine responsive protein-coding gene (laoB) antiparallel overlapping to a CadC-like transcriptional regulator in Escherichia coli O157:H7 Sakai originated by overprinting (2018)

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Thermal resistance of vegetative thermophilic spore forming bacilli in skim milk isolated from dairy Environments (2017)

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Comparison between Listeria sensu stricto and Listeria sensu lato strains identifies novel determinants involved in infection (2017)

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Differentiation of ncRNAs from small mRNAs in Escherichia coli O157:H7 EDL933 (EHEC) by combined RNAseq and RIBOseq-ryhB encodes the regulatory RNA RyhB and a Peptide, RyhP. (2017)

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Complete circular genome sequence and temperature independent adaptation to Anaerobiosis of Listeria weihenstephanensis DSM 24698 (2017)

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Discovery of numerous novel small genes in the intergenic regions of the Escherichia coli O157:H7 Sakai Genome (2017)

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Spoilage of Microfiltered and Pasteurized Extended Shelf Life Milk Is Mainly Induced by Psychrotolerant Spore-Forming Bacteria that often Originate from Recontamination (2017)

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Transcriptional and translational regulation by RNA thermometers, riboswitches and the sRNA DsrA in Escherichia coli O157:H7 Sakai under combined cold and osmotic stress adaptation. (2016)

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Comparative Bioinformatics and Experimental Analysis of the Intergenic Regulatory Regions of Bacillus cereus hbl and nhe Enterotoxin Operons and the Impact of CodY on Virulence Heterogeneity (Mai 2016)

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Acidified nitrite inhibits proliferation of Listeria monocytogenes - Transcriptional analysis of a preservation method (März 2016)

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Translatomics combined with transcriptomics and proteomics reveals novel functional, recently evolved orphan genes in Escherichia coli O157:H7 (EHEC)

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Evidence for the recent origin of a bacterial protein-coding, overlapping orphan gene by evolutionary overprinting (Dez. 2015)

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Massive horizontal gene transfer, strictly vertical inheritance and ancient duplications differentially shape the evolution of Bacillus cereus enterotoxin operons hbl, cytK and nhe (Nov. 2015)