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Chapter 6 not fully capture the range of run-to-run and coupon to coupon variation. Ideally, a larger number of replicates would be used to validate the accuracy and trueness of the observations as described in the ISO standards 5725-2:1998(E) [236]. However in most instances, a compromise between repeated measures of the same experiment and measures of different parameters (strains, conditions, duration of biofilm development) also needs to be reached. This thesis represents one of the most rigorous evaluations of repeatability of measurement of biofilm studied in the CBR and in other biofilm reactor models examining Salmonella biofilm density attached to surfaces. 6.8.6. The use of multiple comparisons in order to extrapolate any differences P values of 0.05 are generally accepted as indicating that the observed degree of difference is unlikely to have occurred by chance alone. However, given that multiple comparisons were made (up to 40 comparisons in some tables), this criterion of significance should be applied with caution. The degree of caution necessary when performing multiple comparisons is because the probability of finding a p value of
Chapter 6 6.9. Main Findings Summary Previous research examining Salmonella biofilm density has tended to focus on a limited number of strains of interest [67, 98], with a single serovar [67, 102, 106, 138, 148, 187-188] or using a single biofilm substrata [111-112, 165, 191]. However, it is difficult to form well founded conclusions if the strains are not compared to other strains and serovars under a variety of conditions and with consideration for repeatability of findings under a given set of conditions. It is of value to consider the surfaces commonly found in food processing settings. The work presented in this thesis enhances the knowledge of Salmonella enterica biofilm density on surfaces, as multiple strains within three serovars of interest S. Agona, S. Typhimurium and S. Enteritidis were compared with more thorough assessment of repeatability than is evident in most published research. The main purpose of the current study was to determine if the S. Agona outbreak strains SAGOXB.0066 formed a more dense biofilm than other strains of S. Agona and/or other serovars of Salmonella commonly associated with foodborne outbreaks. The results show no convincing evidence to demonstrate that the outbreak strain or the variant strain (related to the outbreak) formed a more dense biofilm than other recent strains of S. Agona. This was demonstrated using the CBR and the microtitre plate method. When the biofilm was developed over 48 hours the results suggest that Salmonella biofilm density may be related to serovars. The results indicate that in most cases S. Agona and S. Typhimurium may tend to form a more dense biofilm than S. Enteritidis. These findings were broadly consistent when examined using both the CBR and the microtitre plate method. Page 214
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Salmonella enterica - biofilm forma
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Table of Contents Page Number 1.16.
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Table of Contents Page Number 4.1.2
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Table of Contents Page Number 6.8.4
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List of Abbreviations Table Page Nu
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List of Abbreviations List of Abbre
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Summary of Content Summary of Conte
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“To show your true ability is alw
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Acknowledgements ever met, Fiona th
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Acknowledgements This Ph.D. thesis
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Chapter 1 1.1. Salmonella Salmonell
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Chapter 1 may impose enormous costs
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Chapter 1 cracks or penetration of
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Chapter 1 detected by agglutination
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Chapter 1 become colonized with >10
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Chapter 1 antigens [z27],[z45] [1].
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Chapter 1 S. Agona has also been im
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Chapter 1 isolated from undercooked
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Chapter 1 The S. Typhimurium strain
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Chapter 1 ecosystem with the use of
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Chapter 1 [82]. Previous research h
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Chapter 1 to genes involved in flag
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Chapter 1 observation has also been
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Chapter 1 [119] and flow cell react
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Chapter 1 based disinfectant) the s
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Chapter 1 formation of two strains
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Chapter 1 shield the S. Agona cells
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Chapter 1 Key Objectives of this st
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Chapter 2 2. Abstract Food-borne pa
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Chapter 2 indicated that there may
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Chapter 2 taken from industrial set
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Chapter 2 2.1.4. CDC Biofilm Reacto
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Chapter 2 can be performed without
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Chapter 2 To summarise, previous au
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Chapter 2 2.3. Methods for examinin
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Chapter 2 and the biofilm formed th
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Chapter 2 2.4. Statistical Analysis
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Chapter 2 Table 2.1: Strain charact
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Chapter 2 XII. The gas port and med
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Chapter 2 II. Primary fixative cons
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Chapter 2 IX. Once the conditions w
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Chapter 2 Figure 2.1: Image of CBR
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Chapter 2 2.6. Results 2.6.1. Asses
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Chapter 2 2.6.3. SEM Analysis of su
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Chapter 2 Figure 2.6: Complete remo
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Chapter 2 2.6.5. Mean log 10 densit
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Chapter 2 2.6.6. Mean log 10 densit
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Chapter 2 Table 2.5: Mean log 10 de
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Chapter 2 The results displayed in
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Chapter 2 Table 2.7: Difference bet
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Chapter 2 Table 2.8: The mean log 1
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Chapter 2 Figure 2.7: Graph of the
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Chapter 2 also used “high” soni
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Chapter 2 2.8. Summary All 13 strai
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Chapter 3 3. Abstract It has been e
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Chapter 3 classified as persistent
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Chapter 3 was plated onto TSA for e
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Chapter 3 Figure 3.1: The mean log
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Chapter 3 Figure 3.3: SEM image of
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Chapter 3 Table 3.2: Difference bet
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Chapter 3 3.4.3. Intra-serovar vari
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Chapter 3 3.4.4. Strain variation i
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Chapter 3 3.4.5. The density of bio
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Chapter 3 3.5. Discussion As illust
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Chapter 3 As discussed in section 3
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Chapter 3 increased biofilm appeare
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Chapter 4 Examining the efficacy of
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Chapter 4 through laboratory based
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Chapter 4 acid and quaternary ammon
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Chapter 4 the surface the temperatu
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Chapter 4 availability of multiple
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Chapter 4 peracetic acid (100, 200,
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Chapter 4 As discussed previously,
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Chapter 4 Dey/Engley (Difco) neutra
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Chapter 4 sterilisation was achieve
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Chapter 4 IX. Aliquots of 100µl of
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Chapter 4 XV. XVI. XVII. XVIII. XIX
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Chapter 4 4.3. Results 4.3.1. Suspe
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Chapter 4 Table 4.3: Mean log 10 de
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Chapter 4 Benzalkonium chloride was
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Chapter 4 4.4. Discussion Suspensio
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Chapter 4 effective at eliminating
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Chapter 4 Surprisingly, Nguyen et a
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Chapter 4 though a contact time of
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Chapter 4 provide a more standardis
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Chapter 4 hours instead of the stan
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Chapter 5 5. Abstract Examining bio
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Chapter 5 dry and rough (bdar) morp
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Chapter 5 absence of curli and cell
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Chapter 5 studies such as the micro
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Chapter 5 discussed in chapter 4. T
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Page 186 and 187: Chapter 5 XIII. XIV. XV. XVI. XVII.
Page 188 and 189: Chapter 5 XVI. XVII. XVIII. XIX. XX
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Page 204 and 205: Chapter 5 Table 5.8: Summary of ass
Page 206 and 207: Chapter 5 interpretation therefore
Page 208 and 209: Chapter 5 measures of S. enterica b
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Page 212 and 213: Chapter 5 5.5. Limitations of the s
Page 214 and 215: Chapter 6 Discussion of S. enterica
Page 216 and 217: Chapter 6 However, a number of auth
Page 218 and 219: Chapter 6 It is of interest to exam
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Page 222 and 223: Chapter 6 attributable to a small n
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Page 232 and 233: Chapter 6 responsible for increased
Page 236 and 237: Chapter 6 However, the extent of bi
Page 238 and 239: Chapter 6 6.10. Conclusions and rec
Page 240 and 241: Chapter 6 studies may solve some of
Page 242 and 243: Bibliography Bibliography Page 221
Page 244 and 245: Bibliography 12. T. Takata, J.L., H
Page 246 and 247: Bibliography 29. Barker, J., M. Nae
Page 248 and 249: Bibliography 47. Threlfall, E.J., H
Page 250 and 251: Bibliography 65. CDC. Investigation
Page 252 and 253: Bibliography 83. Ledeboer, N., Frye
Page 254 and 255: Bibliography 100. Chia, T., Goulter
Page 256 and 257: Bibliography 117. Buckingham-Meyer,
Page 258 and 259: Bibliography 133. European Committe
Page 260 and 261: Bibliography Supernatant of a Hafni
Page 262 and 263: Bibliography 165. Díez-García, M.
Page 264 and 265: Bibliography cultivation of Staphyl
Page 266 and 267: Bibliography Compounds. 2012. Appli
Page 268 and 269: Bibliography 215. Buck, et al., A q
Page 270 and 271: Bibliography Canadian Journal of Ps
Page 272 and 273: Appendix 1 Appendix 1— List of Re
Page 274 and 275: Appendix 1 Appendix 1 - List of Equ
Page 276 and 277: Appendix 2 Colour index High outlie
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Appendix 2 Colour index High outlie
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Appendix 3 Appendix 3-Figure 2: PFG
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Appendix 4 Poster Presentation Envi
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