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Microbiological baseline study of swine carcasses at Swedish slaughterhouses.

https://arctichealth.org/en/permalink/ahliterature161544
Source
J Food Prot. 2007 Aug;70(8):1790-7
Publication Type
Article
Date
Aug-2007
Author
M. Lindblad
H. Lindmark
S Thisted Lambertz
R. Lindqvist
Author Affiliation
National Food Administration, P.O. Box 622, SE-751 26 Uppsala, Sweden. mats.lindblad@slv.se
Source
J Food Prot. 2007 Aug;70(8):1790-7
Date
Aug-2007
Language
English
Publication Type
Article
Keywords
Abattoirs
Animals
Bacteria, Aerobic
Campylobacter - isolation & purification
Colony Count, Microbial
Consumer Product Safety
Enterobacteriaceae - isolation & purification
Escherichia coli - isolation & purification
Food contamination - analysis
Food Microbiology
Humans
Listeria monocytogenes - isolation & purification
Polymerase Chain Reaction - methods
Prevalence
Risk assessment
Sweden - epidemiology
Swine - microbiology
Yersinia enterocolitica - isolation & purification
Abstract
This 13-month survey was conducted to estimate the prevalence and counts of foodborne pathogenic bacteria and indicator bacteria on swine carcasses in Sweden. A total of 541 swine carcasses were sampled by swabbing prechill at the 10 largest slaughterhouses in Sweden. Pathogenic Yersinia enterocolitica was detected by PCR in 16% of the samples. The probability of finding Y. enterocolitica increased with increasing counts of Escherichia coli. No samples were positive for Salmonella. The prevalences of Campylobacter, Listeria monocytogenes, and verocytotoxin-producing E. coli were low (1, 2, and 1%, respectively). None of the verocytotoxin-positive enrichments, as determined by a reverse passive latex agglutination assay, tested positive for the virulence genes eaeA or hlyA by PCR. Coagulase-positive staphylococci, E. coli, and Enterobacteriaceae were recovered from 30, 57, and 87% of the samples, respectively, usually at low levels (95th percentiles, 0.79, 1.09, and 1.30 log CFU/cm2, respectively). The mean log level of Enterobacteriaceae was 0.35 log CFU/cm2 higher than that of E. coli on carcasses positive for both bacteria. The mean log level of aerobic microorganisms was 3.48 log CFU/cm2, and the 95th percentile was 4.51 log CFU/cm2. These data may be useful for risk assessment purposes and can serve as a basis for risk management actions, such as the use of E. coli as an alternative indicator organism for process hygiene control.
PubMed ID
17803133 View in PubMed
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Quantitative risk assessment for Listeria monocytogenes in smoked or gravad salmon and rainbow trout in Sweden.

https://arctichealth.org/en/permalink/ahliterature197562
Source
Int J Food Microbiol. 2000 Jul 15;58(3):181-96
Publication Type
Article
Date
Jul-15-2000
Author
R. Lindqvist
A. Westöö
Author Affiliation
National Food Administration, Uppsala, Sweden. roli@slv.se
Source
Int J Food Microbiol. 2000 Jul 15;58(3):181-96
Date
Jul-15-2000
Language
English
Publication Type
Article
Keywords
Animals
Computer simulation
Dose-Response Relationship, Immunologic
Food Microbiology
Hazardous Substances - standards
Humans
Listeria monocytogenes - growth & development - immunology - pathogenicity
Listeriosis - diagnosis - epidemiology - therapy
Models, Biological
Monte Carlo Method
Oncorhynchus mykiss - microbiology
Prevalence
Risk Assessment - methods - standards
Salmon - microbiology
Sweden - epidemiology
Abstract
The objective of the present work was to develop a quantitative risk assessment model in which the exposure and risk of acquiring listeriosis from consumption of packaged smoked or gravad salmon and rainbow trout were estimated. An Excel spreadsheet model was constructed in which variables were represented by distributions based on surveys of L. monocytogenes in these food products, and on demographic and consumption data. Growth or inactivation was not included in the model. The model was run through Monte Carlo simulations using the @Risk software (Palisade Corporation). The probability of illness per serving was calculated using two dose-response models from the literature. The first was an exponential model in which the species specific constant R, that helps define the dose-response curve, previously has been estimated to be 1.18 x 10(-10) based on German data (GR). In this study, R was estimated to 5.6 x 10(-10) based on Swedish data. The second model was a flexible Weibull-Gamma model (WG), with different coefficients for high- and low-risk groups. The exponential model (GR), although conservative and generally overestimating the risk, still predicted a lower probability of illness than the WG-model. The estimated mean risk per serving was 2.8 x 10(-5) (GR, high-risk group), 2.0 x 10(-3) (WG, low-risk group) and 0.016 (WG, high-risk group), respectively. The average number of reported listeriosis cases in Sweden is 37 per year. In comparison, the mean number of annual cases predicted by the risk assessment model was 168 (range 47 to 2800, GR, high-risk group), and 95 000 (range 34 000 to 1.6 x 10(6), WG high-risk group), respectively. If 1 to 10% (uniform distribution) of strains, instead of all, were considered virulent, the mean number of predicted cases would decrease to nine (GR) and 5200 (WG), respectively. The mean annual cumulative individual risk in the high-risk group based on a monthly exposure was estimated to be 4.0 x 10(-4) (range 8.0 x 10(-8) to 5.4 x 10(-3), GR). This risk increased to 1.5 x 10(-3) (range 1.7 x 10(-5) to 9.2 x 10(-3), GR) based on a weekly exposure. The risk assessment model was most sensitive to the input distribution describing the level of contamination and to a lesser degree on the prevalence of L. monocytogenes, the proportion of virulent strains, and serving sizes. A lack of data on the prevalence and concentration of L. monocytogenes in these products, dose-response data and quantitative information on the proportion of virulent strains were identified.
PubMed ID
10939268 View in PubMed
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Subtyping of Listeria monocytogenes isolates recovered from retail ready-to-eat foods, processing plants and listeriosis patients in Sweden 2010.

https://arctichealth.org/en/permalink/ahliterature108260
Source
Int J Food Microbiol. 2013 Aug 16;166(1):186-92
Publication Type
Article
Date
Aug-16-2013
Author
S Thisted Lambertz
S. Ivarsson
G. Lopez-Valladares
M. Sidstedt
R. Lindqvist
Author Affiliation
Science Department, National Food Agency, Sweden. sula@slv.se
Source
Int J Food Microbiol. 2013 Aug 16;166(1):186-92
Date
Aug-16-2013
Language
English
Publication Type
Article
Keywords
Aged
Animals
Electrophoresis, Gel, Pulsed-Field
Environmental Microbiology
Female
Food Handling
Food Microbiology
Genotype
Humans
Listeria monocytogenes - classification - genetics - isolation & purification
Listeriosis - epidemiology - microbiology
Male
Polymerase Chain Reaction
Serotyping
Sweden - epidemiology
Abstract
Identification and prioritisation of food safety interventions requires an understanding of the relationship between food, pathogens and cases. Such understanding can be gained through different approaches, e.g. microbial subtyping to attribute cases of foodborne disease to food vehicles or other sources of illness. In this study, Listeria monocytogenes isolates (n=166) from (i) three categories of ready-to-eat (RTE) foods, (ii) food processing plant environments, and (iii) human listeriosis cases, all sampled during 2010 in Sweden, were subtyped. In addition, 121 isolates from human listeriosis cases, collected 2005-2009, were subtyped. Subtyping consisted of both serotyping (conventional method and PCR) and genotyping using pulsed-field gel electrophoresis (PFGE). Serotype 1/2a dominated in all three groups of isolates (range 73-96%). Eighteen percent of the human isolates (2010) belonged to serotype 4b, but only 1.4% of the food isolates. The food isolates differentiated into 19 pulsotypes (ID=0.843), the human isolates collected 2010 into 31 pulsotypes (ID=0.950) and the processing plant isolates into 22 pulsotypes (ID=0.991). Six of the pulsotypes were shared between the food and human isolates. These pulsotypes comprised 42% of the human isolates and 59% of the food isolates. For some processing plants, there was suggested persistence of one or more specific L. monocytogenes strains, as indicated by repetitive isolation of the same pulsotype from food. This study indicated the presence of L. monocytogenes in the processing plant environment as a likely source of contamination of gravad and cold-smoked fish, and this food category as an important source of human exposure to the pathogen.
PubMed ID
23911759 View in PubMed
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