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Burtscher J, Rudavsky T, Zitz U, Domig KJ. Specificity of the AMP-6000 Method for Enumerating Clostridium Endospores in Milk. Foods 2024; 13:1192. [PMID: 38672865 PMCID: PMC11049612 DOI: 10.3390/foods13081192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 04/04/2024] [Accepted: 04/10/2024] [Indexed: 04/28/2024] Open
Abstract
Enumeration of endospores of butyric acid-forming clostridia in cheese milk is an essential part of milk quality monitoring for cheese producers to avoid late blowing, severe spoilage caused by clostridia during ripening. However, due to the lack of an internationally standardized method, different methods are used and it is important to consider how the choice of method affects the results. This is particularly relevant when clostridial spore counts in milk are considered for quality payments. The aim of this study was to evaluate the specificity of the AMP-6000 method for the enumeration of endospores of cheese spoiling clostridia in milk. First, to assess the prevalence of Clostridium diversity and to determine potential non-target species, we identified isolates from positive reactions of the AMP-6000 method used to quantify clostridial endospores in raw milk and teat skin samples by MALDI-TOF MS. Based on these results, a strain library was designed to evaluate method inclusivity and exclusivity using pure cultures of target and non-target strains according to ISO 16140-2:2016. Most target Clostridium tyrobutyricum strains, as well as all tested C. butyricum and C. sporogenes strains were inclusive. However, C. beijerinckii may be underestimated as only some strains gave positive results. All non-target strains of bacilli and lysinibacilli, but not all paenibacilli, were confirmed to be exclusive. This study provides performance data to better understand the results of microbiological enumeration of butyric acid-forming clostridia in milk and serves as a basis for future methodological considerations and improvements.
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Affiliation(s)
- Johanna Burtscher
- Institute of Food Science, Department of Food Science and Technology, BOKU University, Muthgasse 18, 1190 Vienna, Austria (K.J.D.)
| | - Tamara Rudavsky
- Austrian Competence Centre for Feed and Food Quality, Safety and Innovation (FFoQSI), Technopark 1D, 3430 Tulln, Austria
| | - Ulrike Zitz
- Institute of Food Science, Department of Food Science and Technology, BOKU University, Muthgasse 18, 1190 Vienna, Austria (K.J.D.)
| | - Konrad J. Domig
- Institute of Food Science, Department of Food Science and Technology, BOKU University, Muthgasse 18, 1190 Vienna, Austria (K.J.D.)
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2
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Prinčič L, Burtscher J, Sacken P, Krajnc T, Domig KJ. Clostridium strain FAM25158, a unique endospore-forming bacterium related to Clostridium tyrobutyricum and isolated from Emmental cheese shows low tolerance to salt. Front Microbiol 2024; 15:1353321. [PMID: 38414773 PMCID: PMC10897056 DOI: 10.3389/fmicb.2024.1353321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Accepted: 01/30/2024] [Indexed: 02/29/2024] Open
Abstract
The genus Clostridium is a large and diverse group of species that can cause food spoilage, including late blowing defect (LBD) in cheese. In this study, we investigated the taxonomic status of strain FAM25158 isolated from Emmental cheese with LBD using a polyphasic taxonomic and comparative genomic approach. A 16S rRNA gene sequence phylogeny suggested affiliation to the Clostridium sensu stricto cluster, with Clostridium tyrobutyricum DSM 2637T being the closest related type strain (99.16% sequence similarity). Average Nucleotide Identity (ANI) analysis revealed that strain FAM25158 is at the species threshold with C. tyrobutyricum, with ANI values ranging from 94.70 to 95.26%, while the digital DNA-DNA hybridization values were below the recommended threshold, suggesting that FAM25158 is significantly different from C. tyrobutyricum at the genomic level. Moreover, comparative genomic analysis between FAM25158 and its four closest C. tyrobutyricum relatives revealed a diversity of metabolic pathways, with FAM25158 differing from other C. tyrobutyricum strains by the presence of genes such as scrA, srcB, and scrK, responsible for sucrose utilization, and the absence of many important functional genes associated with cold and osmolality adaptation, which was further supported by phenotypic analyses. Surprisingly, strain FAM25158 exhibited unique physiologic traits, such as an optimal growth temperature of 30°C, in contrast to its closest relatives, C. tyrobutyricum species with an optimal growth temperature of 37°C. Additionally, the growth of FAM25158 was inhibited at NaCl concentrations higher than 0.5%, a remarkable observation considering its origin from cheese. While the results of this study provide novel information on the genetic content of strain FAM25158, the relationship between its genetic content and the observed phenotype remains a topic requiring further investigation.
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Affiliation(s)
- Lucija Prinčič
- Department of Food Science and Technology, Institute of Food Science, University of Natural Resources and Life Sciences, Vienna, Vienna, Austria
| | - Johanna Burtscher
- Department of Food Science and Technology, Institute of Food Science, University of Natural Resources and Life Sciences, Vienna, Vienna, Austria
| | - Paul Sacken
- Department of Food Science and Technology, Institute of Food Science, University of Natural Resources and Life Sciences, Vienna, Vienna, Austria
| | - Tina Krajnc
- Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Konrad J Domig
- Department of Food Science and Technology, Institute of Food Science, University of Natural Resources and Life Sciences, Vienna, Vienna, Austria
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3
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Sánchez C, Garde S, Landete JM, Calzada J, Baker DJ, Evans R, Narbad A, Mayer MJ, Ávila M. Identification, activity and delivery of new LysFA67 endolysin to target cheese spoilage Clostridium tyrobutyricum. Food Microbiol 2024; 117:104401. [PMID: 37919009 DOI: 10.1016/j.fm.2023.104401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 10/03/2023] [Accepted: 10/07/2023] [Indexed: 11/04/2023]
Abstract
Bacteriophages and their endolysins are potential biocontrol agents for the anaerobic spoilage organism Clostridium tyrobutyricum, which causes cheese late blowing defect. This study sequenced and compared the genomes of eight bacteriophages from Spanish dairy farms that were active against C. tyrobutyricum, to identify novel species and phage proteins. Phages vB_CtyS-FA67 and vB_CtyS-FA70 shared >94% intergenomic similarity to each other but neither phage had significant similarity to ΦCTP1, the unique C. tyrobutyricum phage sequenced to date. Taxonomic analysis indicated that both phages belong to the class Caudoviricetes and are related to dsDNA viruses with long non-contractile tails. vB_CtyS-FA67 had no other close relatives and encoded a novel endolysin, LysFA67, predicted to belong to the glycoside hydrolase GH24 family. LysFA67 lysed 93% of C. tyrobutyricum cells after 4 min in turbidity reduction assays, retaining lytic activity at pHs 4.2-8.1 and at 30-45 °C. The endolysin remained stable after 30 d storage at 4, 12 and 25 °C, while its activity decreased at -20 °C. LysFA67 lysed several clostridia species, while common dairy bacteria were not affected. Lactococcus lactis INIA 437, used as a cheese starter, was engineered to deliver LysFA67 and red fluorescent LysFA67-mCherry to dairy products. We demonstrated that these engineered strains were able to maintain lytic activity and fluorescence without affecting their technological properties in milk.
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Affiliation(s)
- Carmen Sánchez
- Departamento de Tecnología de Alimentos, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA-CSIC), Carretera de La Coruña km 7, 28040, Madrid, Spain
| | - Sonia Garde
- Departamento de Tecnología de Alimentos, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA-CSIC), Carretera de La Coruña km 7, 28040, Madrid, Spain.
| | - José María Landete
- Departamento de Tecnología de Alimentos, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA-CSIC), Carretera de La Coruña km 7, 28040, Madrid, Spain
| | - Javier Calzada
- Departamento de Tecnología de Alimentos, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA-CSIC), Carretera de La Coruña km 7, 28040, Madrid, Spain
| | - Dave J Baker
- Science Operations, Quadram Institute Bioscience, Norwich Research Park, Norwich, NR4 7UQ, UK
| | - Rhiannon Evans
- Science Operations, Quadram Institute Bioscience, Norwich Research Park, Norwich, NR4 7UQ, UK
| | - Arjan Narbad
- Food, Microbiome and Health Institute Strategic Programme, Quadram Institute Bioscience, Colney, Norwich, NR4 7UA, UK
| | - Melinda J Mayer
- Food, Microbiome and Health Institute Strategic Programme, Quadram Institute Bioscience, Colney, Norwich, NR4 7UA, UK.
| | - Marta Ávila
- Departamento de Tecnología de Alimentos, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA-CSIC), Carretera de La Coruña km 7, 28040, Madrid, Spain.
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Diarra C, Goetz C, Gagnon M, Roy D, Jean J. Biofilm formation by heat-resistant dairy bacteria: multispecies biofilm model under static and dynamic conditions. Appl Environ Microbiol 2023; 89:e0071323. [PMID: 37732743 PMCID: PMC10617596 DOI: 10.1128/aem.00713-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 07/26/2023] [Indexed: 09/22/2023] Open
Abstract
In the food industry, especially dairy, biofilms can be formed by heat-resistant spoilage and pathogenic bacteria from the farm. Such biofilms may persist throughout the processing chain and contaminate milk and dairy products continuously, increasing equipment cleaning, maintenance costs, and product recalls. Most biofilms are multispecies, yet most studies focus on single-species models. A multispecies model of dairy biofilm was developed under static and dynamic conditions using heat-resistant Bacillus licheniformis, Pseudomonas aeruginosa, Clostridium tyrobutyricum, Enterococcus faecalis, Streptococcus thermophilus, and Rothia kristinae isolated from dairies. C. tyrobutiricum and R. kristinae were weak producers of biofilm, whereas the other four were moderate to strong producers. Based on cross-streaking on agar, P. aeruginosa was found to inhibit B. licheniformis and E. faecalis. In multispecies biofilm formed on stainless steel in a CDC reactor fed microfiltered milk, the strong biofilm producers were dominant while the weak producers were barely detectable. All biofilm matrices were dispersed easily by proteinase K treatment but were less sensitive to DNase or carbohydrases. Further studies are needed to deepen our understanding of multispecies biofilms and interactions within to develop improved preventive strategies to control the proliferation of spoilage and pathogenic bacteria in dairies and other food processing environments. IMPORTANCE A model of multispecies biofilm was created to study biofilm formation by heat-resistant bacteria in the dairy industry. The biofilm formation potential was evaluated under static conditions. A continuous flow version was then developed to study multispecies biofilm formed on stainless steel in microfiltered milk under dynamic conditions encountered in dairy processing equipment. The study of biofilm composition and bacterial interactions therein will lead to more effective means of suppressing bacterial growth on food processing equipment and contamination of products with spoilage and pathogenic bacteria, which represent considerable economic loss.
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Affiliation(s)
- Carine Diarra
- Département des Sciences des Aliments, Institut sur la Nutrition et les Aliments Fonctionnels, Université Laval, Québec, Canada
- Regroupement de recherche pour un lait de qualité optimale (Op+Lait), Saint-Hyacinthe, Québec, Canada
| | - Coralie Goetz
- Département des Sciences des Aliments, Institut sur la Nutrition et les Aliments Fonctionnels, Université Laval, Québec, Canada
- Regroupement de recherche pour un lait de qualité optimale (Op+Lait), Saint-Hyacinthe, Québec, Canada
| | - Mérilie Gagnon
- Département des Sciences des Aliments, Institut sur la Nutrition et les Aliments Fonctionnels, Université Laval, Québec, Canada
- Regroupement de recherche pour un lait de qualité optimale (Op+Lait), Saint-Hyacinthe, Québec, Canada
| | - Denis Roy
- Département des Sciences des Aliments, Institut sur la Nutrition et les Aliments Fonctionnels, Université Laval, Québec, Canada
- Regroupement de recherche pour un lait de qualité optimale (Op+Lait), Saint-Hyacinthe, Québec, Canada
| | - Julie Jean
- Département des Sciences des Aliments, Institut sur la Nutrition et les Aliments Fonctionnels, Université Laval, Québec, Canada
- Regroupement de recherche pour un lait de qualité optimale (Op+Lait), Saint-Hyacinthe, Québec, Canada
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Reis MM, Dixit Y, Carr A, Tu C, Palevich F, Gupta T, Reis MG. Hyperspectral imaging through vacuum packaging for monitoring cheese biochemical transformation caused by Clostridium metabolism. Food Res Int 2023; 169:112866. [PMID: 37254314 DOI: 10.1016/j.foodres.2023.112866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 04/15/2023] [Accepted: 04/18/2023] [Indexed: 06/01/2023]
Abstract
This study developed a novel method for monitoring cheese contamination with Clostridium spores non-invasively using hyperspectral imaging (HSI). The ability of HSI to quantify Clostridium metabolites was investigated with control cheese and cheese manufactured with milk contaminated with Clostridium tyrobutyricum, Clostridium butyricum and Clostridium sporogenes. Microbial count, HSI and SPME-GC-MS data were obtained over 10 weeks of storage. The developed method using HSI successfully quantified butyric acid (R2 = 0.91, RPD = 3.38) a major compound of Clostridium metabolism in cheese. This study creates a new venue to monitor the spatial and temporal development of late blowing defect (LBD) in cheese using fast and non-invasive measurement.
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Affiliation(s)
- Marlon M Reis
- AgResearch, Te Ohu Rangahau Kai, Palmerston North 4474, New Zealand.
| | - Yash Dixit
- AgResearch, Te Ohu Rangahau Kai, Palmerston North 4474, New Zealand
| | - Alistair Carr
- AgResearch, Te Ohu Rangahau Kai, Palmerston North 4474, New Zealand
| | - Christine Tu
- AgResearch, Te Ohu Rangahau Kai, Palmerston North 4474, New Zealand
| | - Faith Palevich
- AgResearch, Te Ohu Rangahau Kai, Palmerston North 4474, New Zealand
| | - Tanushree Gupta
- AgResearch, Te Ohu Rangahau Kai, Palmerston North 4474, New Zealand
| | - Mariza G Reis
- AgResearch, Te Ohu Rangahau Kai, Palmerston North 4474, New Zealand
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6
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Carminati D, Bonvini B, Francolino S, Ghiglietti R, Locci F, Tidona F, Mariut M, Abeni F, Zago M, Giraffa G. Low-Level Clostridial Spores' Milk to Limit the Onset of Late Blowing Defect in Lysozyme-Free, Grana-Type Cheese. Foods 2023; 12:foods12091880. [PMID: 37174418 PMCID: PMC10177814 DOI: 10.3390/foods12091880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 04/26/2023] [Accepted: 04/30/2023] [Indexed: 05/15/2023] Open
Abstract
The growth of clostridial spores during ripening leads to late blowing (LB), which is the main cause of spoilage in Grana Padano Protected Designation of Origin (PDO) cheese and other hard, long-ripened cheeses such as Provolone, Comté, and similar cheeses. This study aimed to verify the cause-effect relationship between the level of clostridial butyric spores (BCS) in milk and the onset of the LB defect. To this end, experimental Grana-type cheeses were produced without lysozyme, using bulk milk with different average BCS content. The vat milk from the so-called "virtuous" farms (L1) contained average levels of BCS of 1.93 ± 0.61 log most probable number (MPN) L-1, while the vat milk from farms with the highest load of spores (L2), were in the order of 2.99 ± 0.69 log MPN L-1. Cheeses after seven months of ripening evidenced a strong connection between BCS level in vat milk and the occurrence of LB defect. In L2 cheeses, which showed an average BCS content of 3.53 ± 1.44 log MPN g-1 (range 1.36-5.04 log MPN g-1), significantly higher than that found in L1 cheeses (p < 0.01), the defect of LB was always present, with Clostridium tyrobutyricum as the only clostridial species identified by species-specific PCR from MPN-positive samples. The L1 cheeses produced in the cold season (C-L1) were free of defects whereas those produced in the warm season (W-L1) showed textural defects, such as slits and cracks, rather than irregular eyes. A further analysis of the data, considering the subset of the cheesemaking trials (W-L1 and W-L2), carried out in the warm season, confirmed the presence of a climate effect that, often in addition to the BCS load in the respective bulk milks (L1 vs. L2), may contribute to explain the significant differences in the chemical composition and some technological parameters between the two series of cheeses. Metagenomic analysis showed that it is not the overall structure of the microbial community that differentiates L1 from L2 cheeses but rather the relative distribution of the species between them. The results of our trials on experimental cheeses suggest that a low-level BCS in vat milk (<200 L-1) could prevent, or limit, the onset of LB in Grana-type and similar cheeses produced without lysozyme.
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Affiliation(s)
- Domenico Carminati
- Council for Agricultural Research and Economics, Research Centre for Animal Production and Aquaculture (CREA-ZA), Via Lombardo 11, 26900 Lodi, Italy
| | - Barbara Bonvini
- Council for Agricultural Research and Economics, Research Centre for Animal Production and Aquaculture (CREA-ZA), Via Lombardo 11, 26900 Lodi, Italy
| | - Salvatore Francolino
- Council for Agricultural Research and Economics, Research Centre for Animal Production and Aquaculture (CREA-ZA), Via Lombardo 11, 26900 Lodi, Italy
| | - Roberta Ghiglietti
- Council for Agricultural Research and Economics, Research Centre for Animal Production and Aquaculture (CREA-ZA), Via Lombardo 11, 26900 Lodi, Italy
| | - Francesco Locci
- Council for Agricultural Research and Economics, Research Centre for Animal Production and Aquaculture (CREA-ZA), Via Lombardo 11, 26900 Lodi, Italy
| | - Flavio Tidona
- Council for Agricultural Research and Economics, Research Centre for Animal Production and Aquaculture (CREA-ZA), Via Lombardo 11, 26900 Lodi, Italy
| | - Monica Mariut
- Council for Agricultural Research and Economics, Research Centre for Animal Production and Aquaculture (CREA-ZA), Via Lombardo 11, 26900 Lodi, Italy
| | - Fabio Abeni
- Council for Agricultural Research and Economics, Research Centre for Animal Production and Aquaculture (CREA-ZA), Via Lombardo 11, 26900 Lodi, Italy
| | - Miriam Zago
- Council for Agricultural Research and Economics, Research Centre for Animal Production and Aquaculture (CREA-ZA), Via Lombardo 11, 26900 Lodi, Italy
| | - Giorgio Giraffa
- Council for Agricultural Research and Economics, Research Centre for Animal Production and Aquaculture (CREA-ZA), Via Lombardo 11, 26900 Lodi, Italy
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7
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Quantitative Detection of Late Blowing Agents C. tyrobutyricum, C. butyricum, and C. sporogenes in Traditional Turkish Cheese by Multiplex Real-Time PCR. FOOD ANAL METHOD 2023. [DOI: 10.1007/s12161-023-02454-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/10/2023]
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8
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Morandi S, Silvetti T, Brasca M. Content and spatial distribution of dairy-related Clostridium spores in Grana Padano cheese during the ripening period. Lebensm Wiss Technol 2022. [DOI: 10.1016/j.lwt.2022.113850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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9
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Giraffa G. The Microbiota of Grana Padano Cheese. A Review. Foods 2021; 10:2632. [PMID: 34828913 PMCID: PMC8621370 DOI: 10.3390/foods10112632] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 10/27/2021] [Accepted: 10/28/2021] [Indexed: 12/23/2022] Open
Abstract
Grana Padano (GP) is the most appreciated and marketed cheese with Protected Designation of Origin in the world. The use of raw milk, the addition of undefined cultures (defined as 'sieroinnesto naturale'), the peculiar manufacturing proces, and the long ripening make the cheese microbiota play a decisive role in defining the quality and the organoleptic properties of the product. The knowledge on the microbial diversity associated with GP has been the subject, in recent years, of several studies aimed at understanding its composition and characteristics in order, on the one hand, to improve its technological performances and, on the other hand, to indirectly enhance the nutritional quality of the product. This review aims to briefly illustrate the main available knowledge on the composition and properties of the GP microbiota, inferred from dozens of studies carried out by both classical microbiology techniques and metagenomic analysis. The paper will essentially, but not exclusively, be focused on the lactic acid bacteria (LAB) derived from starter (SLAB) and the non-starter bacteria, both lactic (NSLAB) and non-lactic, of milk origin.
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Affiliation(s)
- Giorgio Giraffa
- Council for Agricultural Research and Economics, Research Centre for Animal Production and Aquaculture (CREA-ZA), Via Lombardo 11, 26900 Lodi, Italy
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10
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Draft Genome Sequences of 12 Clostridium tyrobutyricum Strains Isolated from Raw Milk and Cheese. Microbiol Resour Announc 2021; 10:e0073521. [PMID: 34591680 PMCID: PMC8483699 DOI: 10.1128/mra.00735-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Clostridium tyrobutyricum is recognized as the main causative agent of late blowing defect—severe spoilage of hard and semihard cheeses. In this work, we present the draft genome sequences of 12 C. tyrobutyricum strains isolated from raw milk and cheese.
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11
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Podrzaj L, Burtscher J, Küller F, Domig KJ. Strain-Dependent Cheese Spoilage Potential of Clostridium tyrobutyricum. Microorganisms 2020; 8:microorganisms8111836. [PMID: 33266400 PMCID: PMC7700369 DOI: 10.3390/microorganisms8111836] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/18/2020] [Accepted: 11/19/2020] [Indexed: 11/23/2022] Open
Abstract
Clostridium tyrobutyricum, a Gram-positive, anaerobic, spore-forming bacterium, is considered as one of the main causative agents for spoilage of hard and semihard cheeses. Growth of C. tyrobutyricum in cheese is critically influenced by ripening temperature and time, pH, salt and lactic acid concentration, moisture and fat content, and the presence of other microorganisms. Previous studies revealed high intraspecies diversity of C. tyrobutyricum strains and variable tolerance toward pH, temperatures, and salt concentrations. These findings indicate that strain-dependent characteristics may be relevant to assess the risk for cheese spoilage if clostridial contamination occurs. In this study, we aimed to compare the phenotypes of 12 C. tyrobutyricum strains which were selected from 157 strains on the basis of genotypic and proteotypic variability. The phenotypic analysis comprised the assessment of gas production and organic acid concentrations in an experimental cheese broth incubated at different temperatures (37, 20, and 14 °C). For all tested strains, delayed gas production at lower incubation temperatures and a strong correlation between gas production and the change in organic acid concentrations were observed. However, considering the time until gas production was visible at different incubation temperatures, a high degree of heterogeneity was found among the tested strains. In addition, variation among replicates of the same strain and differences due to different inoculum levels became evident. This study shows, that, among other factors, strain-specific germination and growth characteristics should be considered to evaluate the risk of cheese spoilage by C. tyrobutyricum.
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Affiliation(s)
- Lucija Podrzaj
- Institute of Food Science, University of Natural Resources and Life Sciences Vienna (BOKU), 1190 Vienna, Austria; (L.P.); (F.K.); (K.J.D.)
- Austrian Competence Centre for Feed and Food Quality, Safety and Innovation (FFoQSI GmbH), Technopark 1C, 3430 Tulln, Austria
| | - Johanna Burtscher
- Institute of Food Science, University of Natural Resources and Life Sciences Vienna (BOKU), 1190 Vienna, Austria; (L.P.); (F.K.); (K.J.D.)
- Correspondence: ; Tel.: +43-1-47654-75456
| | - Franziska Küller
- Institute of Food Science, University of Natural Resources and Life Sciences Vienna (BOKU), 1190 Vienna, Austria; (L.P.); (F.K.); (K.J.D.)
- Austrian Competence Centre for Feed and Food Quality, Safety and Innovation (FFoQSI GmbH), Technopark 1C, 3430 Tulln, Austria
| | - Konrad J. Domig
- Institute of Food Science, University of Natural Resources and Life Sciences Vienna (BOKU), 1190 Vienna, Austria; (L.P.); (F.K.); (K.J.D.)
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12
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Characterization of Clostridium tyrobutyricum Strains Using Three Different Typing Techniques. Microorganisms 2020; 8:microorganisms8071057. [PMID: 32708607 PMCID: PMC7409188 DOI: 10.3390/microorganisms8071057] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 07/08/2020] [Accepted: 07/13/2020] [Indexed: 11/16/2022] Open
Abstract
Clostridium tyrobutyricum is well known as one of the main causative agents of severe cheese spoilage. The metabolism of this anaerobic bacterium during ripening leads to textural and sensory defects in cheese and consequential loss of product value. The potential to induce cheese spoilage, however, may vary among different strains of the same species. Therefore, a better understanding of the intra-species diversity of C. tyrobutyricum may be of practical relevance for the dairy industry. In the present study, we compared the ability of three typing techniques to differentiate 95 C. tyrobutyricum strains on the subspecies level: (1) repetitive element palindromic PCR (rep-PCR) fingerprinting combined with conventional agarose gel electrophoresis, (2) hexaplex-PCR followed by an automated capillary electrophoresis and (3) matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) typing. MALDI-TOF MS fingerprinting provided only moderate reproducibility and low discriminatory power. Both PCR-based methods were highly reproducible and discriminative, with hexaplex-PCR fingerprinting being slightly more discriminative than rep-PCR typing. Overall, a high intra-species diversity was observed among the tested strains, indicating that further investigations on the strain level may be of interest.
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13
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Burtscher J, Hobl L, Kneifel W, Domig KJ. Short communication: Clostridial spore counts in vat milk of Alpine dairies. J Dairy Sci 2020; 103:2111-2116. [PMID: 31954557 DOI: 10.3168/jds.2019-17559] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 11/18/2019] [Indexed: 11/19/2022]
Abstract
One of the most severe quality defects in hard and semi-hard cheese, the late blowing defect, is caused by endospore-forming bacteria of the genus Clostridium. To minimize financial losses and waste of resources due to cheese spoilage, raw milk with elevated clostridial spore counts should not be used for the production of certain cheese types. In this context, threshold values of clostridial spore concentrations that cause quality defects in cheese are still under debate. To improve our understanding about late blowing defects, further information on the correlation between clostridial spore concentrations in milk and cheese quality is indispensable. Thus, the aim of this study was to monitor the microbiological quality of milk used for Alpine cheese production regarding clostridial endospore levels to facilitate the establishment of threshold spore concentrations that guarantee the absence of quality defects in Austrian cheese. For this purpose, we monitored clostridial endospore levels in vat milk of 4 Alpine dairies throughout the summer grazing period in 2018. Surprisingly, we observed almost complete absence of butyric acid-producing clostridia in milk and no blowing defects in cheese. Hence, critical clostridial spore concentrations could not be verified. Moreover, the observed low spore levels reveal that the prohibition of silage feeding and good farming practices effectively minimize clostridial endospore counts in milk and ensure the manufacture of high-quality cheese even if technological possibilities are limited.
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Affiliation(s)
- J Burtscher
- Department of Food Science and Technology, University of Natural Resources and Life Sciences Vienna, Vienna 1190, Austria; FFoQSI, Austrian Competence Centre for Feed and Food Quality, Safety and Innovation, Tulln 3430, Austria.
| | - L Hobl
- Department of Food Science and Technology, University of Natural Resources and Life Sciences Vienna, Vienna 1190, Austria
| | - W Kneifel
- Department of Food Science and Technology, University of Natural Resources and Life Sciences Vienna, Vienna 1190, Austria
| | - K J Domig
- Department of Food Science and Technology, University of Natural Resources and Life Sciences Vienna, Vienna 1190, Austria
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