| 1. |
- Arinder, Pernilla, et al.
(författare)
-
Transfer and Decontamination of S. aureus in Transmission Routes Regarding Hands and Contact Surfaces
- 2016
-
Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 11:6
-
Tidskriftsartikel (refereegranskat)abstract
- Hand hygiene, cleaning and disinfection are pre-requirements for hygiene management in hospital settings and the food industry. In order to facilitate risk management, different contamination scenarios and interventions need to be evaluated. In the present study data on transfer rates and reductions of Staphylococcus aureus were provided in an experimental set-up using artificial skin. Using this methodology, test persons were not exposed with pathogenic bacteria. An exposure assessment model was developed and applied to evaluate different contamination routes and hygiene interventions. The transfer rates of S. aureus from inoculated VITRO-SKIN® to fomites were calculated from blotting series. The VITRO-SKIN® was more prone to spread bacteria than fomites. When different surfaces were cleaned, the reduction of S. aureus varied between <1 and 7 log CFU. It could not be concluded that a certain coupon material, cleaning agent, cleaning wipe, soiling or humidity consistently resulted in a high or low reduction of S. aureus. The reduction of S. aureus and E. coli during hand washing was evaluated on artificial skin, VITRO-SKIN®. The reduction of E. coli on VITRO-SKIN® was similar to the log reduction obtained when washing human hands. The S. aureus count on a human hand was both calculated in different scenarios describing different contamination routes starting from a contaminated hand using the exposure assessment model, and measured on an experimental setup using VITRO-SKIN® for validation. A linear relationship was obtained between the analysed level of S. aureus and the calculated level. However, the calculated levels of S. aureus on the VITRO-SKIN® in the scenarios were 1–1.5 log lower than the analysed level. One of the scenarios was used to study the effect of interventions like hand washing and cleaning of surfaces.
|
|
| 2. |
- Aronsson, Kristina, et al.
(författare)
-
Growth of pulsed electric field exposed Escherichia coli in relation to inactivation and environmental factors
- 2004
-
Ingår i: International Journal of Food Microbiology. - 0168-1605 .- 1879-3460. ; 93:1, s. 1-10
-
Tidskriftsartikel (refereegranskat)abstract
- Pulsed electric fields (PEF) have been proven to inactivate microorganisms during nonthermal conditions and have the potential to replace thermal processing as a method for food preservation. However, there is a need to understand the recovery and growth of survivors and potentially injured microorganisms following PEF processing. The purpose of this investigation was to study the growth of Escherichia coli at 10°C following exposure to electrical field strengths (15, 22.5 and 30 kV/cm) in relation to inactivation and the amount of potentially sublethally injured cells. One medium was used as both a treatment medium and an incubation medium, to study the influence of environmental factors on the inactivation and the growth of the surviving population. The pH (5.0, 6.0 and 7.0) and water activity (1.00, 0.985 and 0.97) of the medium was varied by adding HCl and glycerol, respectively. Growth was followed continuously by measuring the optical density. The time-to-detection (td) and the maximum specific growth rate (?max) were calculated from these data. Results showed that the PEF process did not cause any obvious sublethal injury to the E. coli cells. The number of survivors was a consequence of the combination of electrical field strength and environmental factors, with pH being the most prominent. Interestingly, the ?max of subsequent growth was influenced by the applied electrical field strength during the process, with an increased ?max at more intense electrical field strengths. In addition, the ?max was also influenced by the pH and water activity. The td, which could theoretically be considered as an increase in shelf life, was found to depend on a complex correlation between electrical field strength, pH and water activity. That could be explained by the fact that the td is a combination of the number of survivors, the recovery of sublethal injured cells and the growth rate of the survivors. © 2003 Published by Elsevier B.V.
|
|
| 3. |
- Aronsson, Kristina, et al.
(författare)
-
Inactivation of Escherichia coli, Listeria innocua and Saccharomyces cerevisiae in relation to membrane permeabilization and subsequent leakage of intracellular compounds due to pulsed electric field processing
- 2005
-
Ingår i: International Journal of Food Microbiology. - : Elsevier BV. - 0168-1605 .- 1879-3460. ; 99:1, s. 19-32
-
Tidskriftsartikel (refereegranskat)abstract
- Membrane permeabilization, caused by pulsed electric field (PEF) processing of microbial cells, was investigated by measurement of propidium iodide (PI) uptake with flow cytometry. Inactivation of Escherichia coli, Listeria innocua and Saccharomyces cerevisiae was determined by viable counts, and leakage of intracellular compounds, such as ATP and UV-absorbing substances, was measured in the extracellular environment. Electrical field strength and pulse duration influenced membrane permeabilization of all three tested organisms of which S. cerevisiae was the most PEF sensitive, followed by E. coli and L. innocua. It was shown by viable counts, PI uptake and leakage of intracellular compounds that L. innocua was the most resistant. Increased inactivation corresponded to greater numbers of permeabilized cells, which were reflected by increased PI uptake and larger amounts of intracellular compounds leaking from cells. For E. coli and L. innocua, a linear relationship was observed between the number of inactivated cells (determined as CFU) and cells with permeated membranes (determined by PI uptake), with higher number of inactivated cells than permeated cells. Increased leakage of intracellular compounds with increasing treatment severity provided further evidence that cells were permeabilized. For S. cerevisiae, there was higher PI uptake after PEF treatments, although very little or no inactivation was observed. Results suggest that E. coli and L. innocua cells, which took up PI, lost their ability to multiply, whereas cells of S. cerevisiae, which also took up PI, were not necessarily lethally permeabilized. © 2004 Elsevier B.V. All rights reserved.
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Blixt, Y., et al.
(författare)
-
Interlaboratory random amplified polymorphic DNA typing of Yersinia enterocolitica and Y. enterocolitica-like bacteria
- 2003
-
Ingår i: International Journal of Food Microbiology. - 0168-1605 .- 1879-3460. ; 83:1, s. 15-26
-
Tidskriftsartikel (refereegranskat)abstract
- A random amplified polymorphic DNA (RAPD) protocol was developed for interlaboratory use to discriminate food-borne Yersinia enterocolitica O:3 from other serogroups of Y. enterocolitica and from Y. enterocolitica-like species. Factors that were studied regarding the RAPD performance were choice of primers and concentration of PCR reagents (template DNA, MgCl 2, primer and Taq DNA polymerase). A factorial design experiment was performed to identify the optimal concentrations of the PCR reagents. The experiment showed that the concentration of the PCR reagents tested significantly affected the number of distinct RAPD products. The RAPD protocol developed was evaluated regarding its discrimination ability using 70 different Yersinia strains. Cluster analysis of the RAPD patterns obtained revealed three main groups representing (i) Y. pseudotuberculosis, (ii) Y. enterocolitica and (iii) Y. kristensenii, Y. frederiksenii, Y. intermedia and Y. ruckeri. Within the Y. enterocolitica group, the European serovar (O:3) and the North American serovar (O:8) could be clearly separated from each other. All Y. enterocolitica O:3 strains were found in one cluster which could be further divided into two subclusters, representing the geographical origin of the isolates. Thus, one of the subclusters contained Y. enterocolitica O:3 strains originating from Sweden, Finland and Norway, while Danish and English O:3 strains were found in another subcluster together with O:9 and O:5,27 strains. The repeatability (intralaboratory) and reproducibility (interlaboratory) of the RAPD protocol were tested using 15 Yersinia strains representing different RAPD patterns. The intralaboratory and the interlaboratory studies gave similarity coefficients of the same magnitude (generally >70%) for the individual strains. In the present study, it was shown that interreproducible RAPD results could be achieved by appropriate optimisation of the RAPD protocol. Furthermore, the study reflects the heterogeneous genetic diversity of the Y. enterocolitica species. © 2002 Elsevier Science B.V. All rights reserved.
|
|
| 7. |
- Borch, Elisabeth, et al.
(författare)
-
Bacteriological safety issues in red meat and ready-to-eat meat products, as well as control measures
- 2002
-
Ingår i: Meat Science. - 0309-1740 .- 1873-4138. ; 62:3, s. 381-390
-
Tidskriftsartikel (refereegranskat)abstract
- The importance of Eschericha coli O157, Listeria monocytogenes and Salmonella typhimurium DT104 as meat-borne pathogens is well established. Pathogenic bacteria such as Aeromonas spp., Arcobacter spp., psychrotrophic Bacillus cereus, Campylobacter spp., Clostridium botulinum and non-invasive Listeria monocytogenes can be regarded as rookies, but not yet firmly associated with today's production of red meat and meat products. The development of PCR and other DNA-based techniques will shed new light on so called emerging pathogens. Important safety issues in meat production, such as insufficient cleaning and disinfection (including the stable/lairage, processing environment), carcass decontamination and chilling, and cross contamination are discussed. Furthermore, probability modelling of survival and growth is identified as an important way to achieve a better understanding of how to deal with the complexity of further processing, including heat treatment and storage. © 2002 Elsevier Science Ltd. All rights reserved.
|
|
| 8. |
- Borch, Elisabeth
(författare)
-
Green Cleaning - Utveckling av testbädden Cleaning Innovation
- 2017
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- En ökad användning av miljösmart teknik och förfarande vid rengöring och desinfektion i livsmedelsindustrin förväntas leda till mindre miljöpåverkan genom mindre vatten-, energi-, kemikalie- och materialförbrukning och mindre matsvinn. Detta gynnar också tillväxten hos miljöteknikföretag som bidrar med gröna lösningar. Testbädden Cleaning Innovation (www.cleaninginnovation.se) medverkar till utveckling av miljösmarta och effektiva metoder för rengöring och desinfektion i många branscher. Huvudintressenter är leverantörer/utvecklare av kemikalier, utrustning eller material; hygienföretag; livsmedelsföretag; offentliga aktörer. Cleaning Innovation, som ägs av RISE, är en öppen, oberoende testbädd och erbjuder utvärdering av teknik, kemikalier, material, utrustning och metoder. Testbädden bygger på samverkan mellan olika typer av verksamheter inom RISE (Research Institutes of Sweden) inriktade mot mikrobiologi, miljö, processteknik, certifiering, mätteknik, kemi, material, energiteknik samt med hygienteknikföretaget Lagafors AB. Inom Cleaning Innovation finns marknadskunskap, tvärvetenskaplig kompetens, analys-, beräknings- och mätutrustning, laboratorier samt testutrustningar i pilotskala. I projektet utvecklades befintlig verksamhet avseende testlokal, utrustning och produkterbjudande. Ett viktigt resultat från projektet är att vi har genomfört mer än 10 projekt där utvärdering av renhet och desinfektion görs med kunder. Eftersom detta är betydligt mer än planerat har egen finansiering blev betydligt högre än budgeterad. Detta visar på ett bra utbud och en tydlig marknad. Vi har också breddat vår målgrupp och inkluderar nu alla branscher med behov av rengöring och desinfektion; i motsats till bara livsmedelsindustrin som beskrivit i projektansökan.Testbädden Cleaning Innovation lanserades 29 november 2016. Cleaning Innovations utveckling i framtiden ser ljus ut och har en stark och naturlig förankring inom RISE. Framtidsplanerna involverar ett succesivt bräddande till kunder inom fler industrityper och en långsam expansion av verksamheten.
|
|
| 9. |
- Borch, Elisabeth, et al.
(författare)
-
Influence of long-chain polyphosphate and heat treatment on Clostridium cochlearium and Clostridium sporogenes isolated from processed cheese spread
- 2007
-
Ingår i: Journal of Food Protection. - 0362-028X .- 1944-9097. ; 70:3, s. 744-747
-
Tidskriftsartikel (refereegranskat)abstract
- The outgrowth of Clostridium spp. spores causes spoilage in processed cheese products due to gas and off-odor formation. The present study focuses on the response of spores of Clostridium sporogenes and Clostridium cochlearium at 25°C to polyphosphate, both alone and in combination with heat treatment. The two strains used were isolated from spoiled cheese spread. The addition of 1.5% polyphosphate but not 0.75% polyphosphate totally inhibited the growth of C. sporogenes SIK4.3; in contrast, 0.75% polyphosphate was sufficient to totally inhibit C. cochlearium CCUG 45978. The highest polyphosphate concentration tested (1.5%) was sporicidal for C. sporogenes SIK4.3 but not for C. cochlearium CCUG 45978. When 0.75% polyphosphate Bekaplus FS was combined with a holding time of 5 min at 98°C, no survival or growth of C. sporogenes SIK4.3 was detected; however, the same effect was not achieved through heating alone or through application of polyphosphate alone. C. cochlearium CCUG 45978 was more heat tolerant, as shown by higher D-values. In conclusion, the results strongly suggest that polyphosphate Bekaplus FS has the potential to restrict the growth of C. sporogenes and C. cochlearium in cheese spread stored at ambient storage temperature. Experiments with cheese are needed in order to verify this effect. Copyright ©, International Association for Food Protection.
|
|
| 10. |
- Dahlenborg, Maria, et al.
(författare)
-
Prevalence of Clostridium botulinum types B, E, and F in faecal samples from Swedish cattle.
- 2003
-
Ingår i: International Journal of Food Microbiology. - 0168-1605 .- 1879-3460. ; 82:2, s. 105-110
-
Tidskriftsartikel (refereegranskat)abstract
- Faeces were collected from 60 cows at three slaughterhouses situated in southern and central Sweden. The faecal samples were collected during two sampling periods over the year, summer and winter. All samples were analysed for the presence of Clostridium botulinum spores, according to a combined selection and enrichment PCR procedure. One PCR assay was specific for part of the type B neurotoxin gene, while the other assay was specific for both type E and F neurotoxin genes. The prevalence of C. botulinum in Swedish cattle was established to be 73% for non-proteolytic type B and less than 5% for types E and F. Twenty-eight (64%) of the positive faecal samples had a spore load of less than 4 spores/g. Statistical analysis (ANOVA) showed that seasonal variation (summer and winter) had a significant effect on the prevalence of C. botulinum type B in cattle, whereas the effect of geographical location of rearing of the cattle (southern and central Sweden) was less significant.
|
|
