| 51. |
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| 52. |
- Loncarevic, Semir, et al.
(författare)
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The clones of Listeria monocytogenes detected in food depend on the method used
- 1996
-
Ingår i: Letters in Applied Microbiology. - : Blackwell Science. - 0266-8254 .- 1472-765X. ; 22:5, s. 381-384
-
Tidskriftsartikel (refereegranskat)abstract
- Restriction enzyme analysis (REA) with pulsed-field gel electrophoresis (PFGE) has been used to characterize and compare Listeria monocytogenes strains isolated from foods by two methods, an enrichment procedure and a direct plating procedure. In total 151 isolates from nine foods were investigated, In six of the foods (101 strains investigated) only one clone of L, monocytogenes was found irrespective of the method used. In three foods (50 strains investigated) the direct plating procedure yielded more clones than the enrichment procedure. At the most, five clones were detected in the same food. The results presented here indicate that direct plating from the food reveals more L, monocytogenes clones than revealed by an enrichment procedure.
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| 53. |
- Lopez-Valladares, Gloria, 1963-, et al.
(författare)
-
Human isolates of Listeria monocytogenes in Sweden during half a century (1958-2010)
- 2014
-
Ingår i: Epidemiology and Infection. - 0950-2688 .- 1469-4409. ; 142, s. 2251-2260
-
Tidskriftsartikel (refereegranskat)abstract
- Isolates of Listeria monocytogenes (n=932) isolated in Sweden during 1958–2010 from human patients with invasive listeriosis were characterized by serotyping and pulsed-field gel electrophoresis (PFGE) (AscI). Of the 932 isolates, 183 different PFGE types were identified, of which 83 were each represented by only one isolate. In all, 483 serovar 1/2a isolates were distributed over 114 PFGE types; 90 serovar 1/2b isolates gave 32 PFGE types; 21 serovar 1/2c isolates gave nine PFGE types; three serovar 3b isolates gave one PFGE type; and, 335 serovar 4b isolates gave 31 PFGE types. During the 1980s in Sweden, several serovar 4b cases were associated with the consumption of European raw soft cheese. However, as cheese-production hygiene has improved, the number of 4b cases has decreased. Since 1996, serovar 1/2a has been the dominant L. monocytogenes serovar in human listeriosis in Sweden. Therefore, based on current serovars and PFGE types, an association between human cases of listeriosis and the consumption of vacuum-packed gravad and cold-smoked salmon is suggested.
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| 54. |
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| 55. |
- Lopez-Valladares, Gloria, 1963-, et al.
(författare)
-
Implicated food products for listeriosis and changes in serovars of Listeria monocytogenes affecting humans in recent decades
- 2018
-
Ingår i: Foodborne pathogens and disease. - : Mary Ann Liebert. - 1535-3141 .- 1556-7125. ; 15:7, s. 387-397
-
Tidskriftsartikel (refereegranskat)abstract
- Listeriosis is a foodborne disease with a high fatality rate, and infection is mostly transmitted through ready-toeat(RTE) foods contaminated with Listeria monocytogenes, such as gravad/smoked fish, soft cheeses, andsliced processed delicatessen (deli) meat. Food products/dishes stored in vacuum or in modified atmospheresand with extended refrigerator shelf lives provide an opportunity for L. monocytogenes to multiply to largenumbers toward the end of the shelf life. Elderly, pregnant women, neonates, and immunocompromisedindividuals are particularly susceptible to L. monocytogenes. Listeriosis in humans manifests primarily assepticemia, meningitis, encephalitis, gastrointestinal infection, and abortion. In the mid 1990s and early 2000s ashift from L. monocytogenes serovar 4b to serovar 1/2a causing human listeriosis occurred, and serovar 1/2a isbecoming more frequently linked to outbreaks of listeriosis, particularly in Europe and Northern America.Consumer lifestyle has changed, and less time is available for food preparation. Modern lifestyle has markedlychanged eating habits worldwide, with a consequent increased demand for RTE foods; therefore, more RTE andtake away foods are consumed. There is a concern that many Listeria outbreaks are reported from hospitals.Therefore, it is vitally important that foods (especially cooked and chilled) delivered to hospitals and residentialhomes for senior citizens and elderly people are reheated to at least 72C: cold food, such as turkey deli meatand cold-smoked and gravad salmon should be free from L. monocytogenes. Several countries have zerotolerance for RTE foods that support the growth of Listeria.
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| 56. |
- Lopez-Valladares, Gloria, 1963-, et al.
(författare)
-
Lineage II (Serovar 1/2a and 1/2c) Human Listeria monocytogenes Pulsed-Field Gel Electrophoresis Types Divided into PFGE Groups Using the Band Patterns Below 145.5 kb
- 2017
-
Ingår i: Foodborne pathogens and disease. - New Rochelle, USA : Mary Ann Liebert. - 1535-3141 .- 1556-7125. ; 14:1, s. 8-16
-
Tidskriftsartikel (refereegranskat)abstract
- Among 504 clinical lineage II isolates of Listeria monocytogenes isolated during 1958-2010 in Sweden, 119 pulsed-field gel electrophoresis (PFGE) types (AscI) have been identified based on the number and distribution of all banding patterns in each DNA profile. In this study, these types were further divided into PFGE groups based on the configuration of small bands with sizes <145.5 kb. The 504 isolates included 483 serovar 1/2a isolates distributed into 114 PFGE types and 21 serovar 1/2c isolates distributed into 9 PFGE types; these were further divided into 21 PFGE groups. PFGE group, that is, configuration of small bands below 145.5 kb, and serovars were correlated. L. monocytogenes isolates belonging to PFGE groups A, B, C, E, F, H, K, L, M, S, V, W, Y, and Ö-6 to Ö-12 shared serovar 1/2a, with one exception. PFGE group E also included two PFGE types sharing serovar 1/2c and four PFGE types belonging to either serovar 1/2a or 1/2c. Isolates belonging to PFGE group N shared serovar 1/2c. In contrast to lineage I isolates, small fragments <33.3 kb were visible in all L. monocytogenes isolates belonging to lineage II. In the results from both the present and previous studies, the genomic region of small bands was genetically more conservative than in large bands. The distribution of these small bands established the relatedness of strains and defined a genetic marker for both lineages I and II, while also establishing their serogroup. The division of L. monocytogenes PFGE types into PFGE groups is advantageous as the profile of every new isolate can be identified easily and quickly through first studying the PFGE group affiliation of the isolate based on the smaller band patterns <145.5 kb, and then identifying the PFGE type based on the band patterns >145.5 kb.
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| 57. |
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| 58. |
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| 59. |
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| 60. |
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| 61. |
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| 62. |
- Parihar, Vishal Singh, et al.
(författare)
-
Characterization of human invasive isolates of Listeria monocytogenes in Sweden 1986-2007
- 2008
-
Ingår i: Foodborne pathogens and disease. - : Mary Ann Liebert. - 1535-3141 .- 1556-7125. ; 5:6, s. 755-761
-
Tidskriftsartikel (refereegranskat)abstract
- Since 1986, 68% of the Listeria monocytogenes isolates from human cases of invasive listeriosis in Sweden are available for retrospective studies. The aim of the present study was to characterize 601 human invasive isolates of L. monocytogenes in Sweden from 1986 to 2007 by using serotyping and pulsed-field gel electrophoresis. Since 1996, serovar 4b was permanently reduced to the second or third most common serovar in human cases in Sweden. During the latter period, 2000-2007, only 13% belonged to serovar 4b and 71% to 1/2a. The dendrogram, based on pulsovars, reveals two clusters with different serovars. Cluster 1 exhibits serovars 4b and 1/2b, whereas cluster 2 consists of serovar 1/2a. Serovar 1/2a seems to be more heterogeneous than serovar 4b.
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| 63. |
- Parihar, Vishal, 1979-, et al.
(författare)
-
Zoonotic aspects of Listeria monocytogenes
- 2004
-
Ingår i: ISOPOL XV – XV International Symposium on Problems of Listeriosis, Uppsala, Sweden, September 12–15, 2004. - Uppsala. ; , s. Abstract no. 128-
-
Konferensbidrag (refereegranskat)
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| 64. |
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| 65. |
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| 66. |
- Tham, Wilhelm, 1951-, et al.
(författare)
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A case of food-brone listeriosis in Sweden, 1993
- 1994
-
Ingår i: XVII. Nordic Veterinary Congress. - Reykjavik, Iceland : Icelandic Veterinary Association. ; , s. 82-82, s. 82-82
-
Konferensbidrag (refereegranskat)
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| 67. |
- Tham, Wilhelm, 1951-, et al.
(författare)
-
A listeriosis patient infected with two different Listeria monocytogenes strains
- 2002
-
Ingår i: Epidemiology and Infection. - 0950-2688 .- 1469-4409. ; 128:1, s. 105-106
-
Tidskriftsartikel (refereegranskat)abstract
- Normally, only one isolate of Listeria monocytogenes from a case of listeriosis is subjected to characterization. Here we show that two isolates from different sites of the body were not the same strain. Such a phenomenon may not have any clinical relevance, although it may confuse the epidemiologist trying to match infection source with infection target.
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| 68. |
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| 69. |
- Tham, Wilhelm, 1951-, et al.
(författare)
-
Bacteriological quality of on-farm manufactured goat cheese
- 1990
-
Ingår i: Epidemiology and Infection. - : Cambridge University Press. - 0950-2688 .- 1469-4409. ; 104, s. 87-100
-
Tidskriftsartikel (refereegranskat)abstract
- The bacteriological quality of 198 ripened soft or semi-soft goat cheeses obtained from dairy farms and the retail trade was investigated. The cheeses were examined for total counts of aerobic bacteria, coliform bacteria (37 and 44 °C respectively), enterocoeci, coagulase positive staphylococci,Bacillus cereusandClostridium perfringens.Cheeses obtained from dairy-farms were also determined for pH value. In terms of all tests performed, cheeses made of heat-treated milk with starter culture had the best prospects for fulfilling the criteria for 'fit for consumption '. Cheeses made of raw milk without starter culture made up the most unsatisfactory group from a food-hygiene point of view. Bacteriological guidelines for on-farm manufactured goat cheese are suggested.
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| 70. |
- Tham, Wilhelm, 1951-, et al.
(författare)
-
Epdemiology of listeriosis in Sweden
- 1991
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Ingår i: 8th World Congress of Food Science and Technology,Program and AbstractsToronto, Canada, September 29–October 4, 1991. ; , s. 226-226
-
Konferensbidrag (refereegranskat)
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| 71. |
- Tham, Wilhelm, 1951-, et al.
(författare)
-
Epidemiology of listeriosis in Sweden
- 1991
-
Ingår i: Compte-rendus de la Conference Internationale,Proceedings of the International Conference,Listeria et Sécurité AlimentaireListeria and Food Safety13–14 Juin/June 1991 – LAVAL – France. - LAVAL CEDEX, FRANCE. ; , s. 188-188
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Konferensbidrag (refereegranskat)
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| 72. |
- Tham, Wilhelm, 1951-, et al.
(författare)
-
Europeisk epidemisk fagovar även i Sverige
- 1994
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Ingår i: Svensk veterinärtidning. - Stockholm : Sveriges veterinärförbund. - 0346-2250. ; 46:15, s. 693-695
-
Tidskriftsartikel (refereegranskat)
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| 73. |
- Tham, Wilhelm, 1951-, et al.
(författare)
-
Histamine formation by enterococci in goat cheese
- 1990
-
Ingår i: International Journal of Food Microbiology. - : Elsevier. - 0168-1605 .- 1879-3460. ; 11:3-4, s. 225-229
-
Tidskriftsartikel (refereegranskat)abstract
- Cheeses were made of heat-treated goat milk inoculated with large numbers of a histamine-producing strain of Streptococcus faecium or a non-histamine-producing strain of S. faecalis. Every second week during ripening (91 days) the cheeses were sampled for histamine analyses and bacteriological analyses. The numbers of enterococci remained high throughout the whole period of investigation and the maximum amount of histamine detected was 8.2-mu-g/g in one of the cheeses. The enterococci seem to have no relevance from a histamine intoxication point of view in cheeses of this kind.
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| 74. |
- Tham, Wilhelm, 1951-, et al.
(författare)
-
Lessons from an outbreak of listeriosis related to vacuum-packed gravad and cold-smoked fish
- 2000
-
Ingår i: International Journal of Food Microbiology. - 0168-1605 .- 1879-3460. ; 62:3, s. 173-175
-
Tidskriftsartikel (refereegranskat)abstract
- The first lesson learned from this outbreak was that vacuum-packed rainbow trout is not only an excellent medium for the growth of Listeria monocytogenes, but may also cause human listeriosis. Another lesson is that one single fish processing plant may spread multiple clonal types of L. monocytogenes by selling contaminated products to consumers. Thus, when investigating fish-borne outbreaks of listeriosis one should identify and type several isolates of L. monocytogenes from each food and environmental sample, since multiple clonal types might be present. The outbreak described in this paper involved at least eight human cases, three clonal types of L. monocytogenes, and lasted for 11 months. During the outbreak investigation, L. monocytogenes was also isolated from another brand of rainbow trout found in the refrigerator of one of the patients. These latter isolates belonged to a clonal type not associated with the outbreak. However, this clonal type is of considerable interest since it has been associated with foodborne outbreaks of listeriosis in several countries, and is also the second most common clonal type among human clinical isolates of L. monocytogenes in Sweden. Besides the described outbreak, it is likely that vacuum-packed, cold-smoked and gravad rainbow trout have been involved in additional cases of foodborne listeriosis in Sweden.
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| 75. |
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| 76. |
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| 77. |
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| 78. |
- Tham, Wilhelm, 1951-, et al.
(författare)
-
Listeria monocytogenes isolated from soft cheese
- 1988
-
Ingår i: The Veterinary Record. - : British Veterinary Association. - 0042-4900 .- 2042-7670. ; 122:22, s. 539-540
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Tidskriftsartikel (refereegranskat)
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| 79. |
- Tham, Wilhelm, 1951-, et al.
(författare)
-
Listeria monocytogenes subtypes associated with mortality among fallow deer (Dama dama)
- 1999
-
Ingår i: Journal of zoo and wildlife medicine. - 1042-7260 .- 1937-2825. ; 30:4, s. 545-549
-
Tidskriftsartikel (refereegranskat)abstract
- Different subtypes of Listeria monocytogenes were isolated from various animal and environmental samples during an episode of increased mortality on a fallow deer (Dama dama) farm. During a 4-wk period, six fallow deer died, including four does, one fawn, and one adult buck. Prior to death, one of the does had exhibited central nervous system signs characteristic of listeriosis. Postmortem examination of the six deer showed no histologic changes typical of listeriosis, although inflammatory changes were present in several organs. Different subtypes of L. monocytogenes were isolated from brain samples from six deer, from fodder and soil from the deer feeding area, and from faces of some healthy animals on the farm. Listeria monocytogenes, which was frequently isolated in the environment of the farm, was considered the probable major cause of mortality in these fallow deer.
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| 80. |
- Tham, Wilhelm, 1951-, et al.
(författare)
-
Listeria och Erysipelothrix
- 2015. - 1
-
Ingår i: Medicinsk mikrobiologi & immunologi. - Lund : Studentlitteratur AB. - 9789144038681 ; , s. 210-214
-
Bokkapitel (refereegranskat)abstract
- Släktena Listeria och Erysipelothrix hör till gruppen grampositiva, icke-sporbildande regelbundet formade stavar. Gruppen är mycket heterogen och inkluderar både patogena och apatogena bakterier.
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| 81. |
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| 82. |
|
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| 83. |
- Tham, Wilhelm, 1951-, et al.
(författare)
-
Listerios
- 2001
-
Ingår i: Zoonoser. - Lund : Studentlitteratur AB. - 9144012101 ; , s. 104-111
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Bokkapitel (refereegranskat)
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| 84. |
- Tham, Wilhelm, 1951-, et al.
(författare)
-
Listeriosis
- 1986
-
Ingår i: Food Laboratory Newsletter. - Uppsala : The Swedish National Food Administration. - 0282-1338. ; May:6, s. 38-39
-
Tidskriftsartikel (refereegranskat)
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| 85. |
|
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| 86. |
- Tham, Wilhelm, 1951-, et al.
(författare)
-
More than one variant of Listeria monocytogenes isolated from each of two human cases of invasive listeriosis
- 2007
-
Ingår i: Epidemiology and Infection. - 0950-2688 .- 1469-4409. ; 135:5, s. 854-856
-
Tidskriftsartikel (refereegranskat)abstract
- Two variants of Listeria monocytogenes were isolated from blood cultures from each of two patients with listeriosis. Each variant displayed a two-band difference in DNA profile from the other by pulsed-field gel electrophoresis. Although this difference in profile is insufficient to distinguish clearly between the variants, the possibility of co-infection with different strains of L. monocytogenes needs to be considered. We suggest that more than one colony should be selected for molecular typing to aid interpretation during investigation of the sources and routes of Listeria infection.
|
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| 87. |
- Tham, Wilhelm, 1951-, et al.
(författare)
-
Myter och nyheter om listerios
- 1990
-
Ingår i: Allmänt Veterinärmöte 1990. - Stockholm : Sveriges veterinärförbund. ; , s. 125-130
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 88. |
- Tham, Wilhelm, 1951-, et al.
(författare)
-
Pastörisering är ett stort framsteg
- 2022
-
Ingår i: Svenska Dagbladet. - : Hb Svenska dagbladets AB & Co. - 1101-2412. ; :14 september
-
Tidskriftsartikel (populärvet., debatt m.m.)
|
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| 89. |
|
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| 90. |
- Tham, Wilhelm, 1951-, et al.
(författare)
-
Swedish human cases of Listeriosis, 1958–1999 : Visulized by LEGO Bricks
- 2000
-
Ingår i: Nordic PFGE meeting January 27–28, 2000. Collection of abstracts. Department of Food Hygiene, Faculty of Veterinary Medicine, SLU, Uppsala. - Uppsala : Dep of Food Hygiene, Faculty of Veterinary Medicine, SLU. - 9157659621 ; , s. 27-27
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Konferensbidrag (refereegranskat)
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| 91. |
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| 92. |
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| 93. |
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| 94. |
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| 95. |
- Unnerstad, Helle, et al.
(författare)
-
Division of Listeria monocytogenes serovar 1/2a strains into two groups by PCR and restriction enzyme analysis
- 1999
-
Ingår i: Applied and Environmental Microbiology. - Washington DC, USA : American Society for Microbiology. - 0099-2240 .- 1098-5336. ; 65:5, s. 2054-2056
-
Tidskriftsartikel (refereegranskat)abstract
- Altogether, 100 strains of Listeria monocytogenes serovar 1/2a isolated from humans, animals, food, and the environment were typed by a combination of PCR and restriction enzyme analysis (REA). A PCR product of 2,916 bp, containing the downstream end of the gene inlA (955 bp), the space between inlA and inlB (85 bp), and 1,876 bp of the gene inlB, was cleaved with the enzyme AluI, and the fragments generated were separated by gel electrophoresis. By this method two different cleavage patterns were obtained. Seventy of the 100 strains shared one restriction profile, and the remaining 30 strains shared the second one. No relation was found between the types differentiated by PCR-REA and the origins of the strains.
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| 96. |
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| 97. |
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| 98. |
- Unnerstad, Helle, et al.
(författare)
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Pyrosequencing as a method for grouping of Listeria monocytogenes strains on the basis of single-nucleotide polymorphisms in the inlB gene
- 2001
-
Ingår i: Applied and Environmental Microbiology. - Washington, USA : American Society for Microbiology. - 0099-2240 .- 1098-5336. ; 67:11, s. 5339-5342
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Tidskriftsartikel (refereegranskat)abstract
- By using pyrosequencing (i.e., sequencing by synthesis) 106 strains of different serovars of Listeria monocytogenes were rapidly grouped into four categories based on nucleotide variations at positions 1575 and 1578 of the inlB gene. Strains of serovars 1/2a and 1/2c constituted one group, and strains of serovars 1/2b and 3b constituted another group, whereas serovar 4b strains were separated into two groups.
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| 99. |
- Waak, Elisabet, et al.
(författare)
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Comparison of the ISO and IDF methods for detection of Listeria monocytogenes in blue veined cheese
- 1999
-
Ingår i: International Dairy Journal. - Oxon, United Kingdom : Elsevier. - 0958-6946 .- 1879-0143. ; 9, s. 149-155
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Tidskriftsartikel (refereegranskat)abstract
- The International Dairy Federation Revised Provisional IDF Standard 143:1990 (1990) is compared with the ISO Draft International Standard ISO/DIS 11290-1 (1995) for detection of Listeria monocytogenes in inoculated samples of the blue veined cheeses Gorgonzola and AG delost (Swedish blue mould cheese) and in non-inoculated market cheeses of mostly soft mould cheese. The ISO method detected L. monocytogenes signi"cantly more frequently than the IDF method when inoculated Gorgonzola samples were analysed. For inoculated AG delost, and non-inoculated market cheeses the methods were equally good. The selective isolation media PALCAM and Oxford Listeria selective agar, were compared for recovery of Listeria spp. Less growth of non-Listeria colonies was obtained on PALCAM agar compared to Oxford Listeria selective agar especially after the primary enrichment step of the ISO method. Consequently, it was easier to identify and isolate growth of Listeria species from the cheeses on the PALCAM agar.
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| 100. |
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