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School of Biosciences, Division of
Food Sciences
   
   
  
 

Christine Dodd

Professor of Food Microbiology, Faculty of Science

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Research Summary

My research has been directed at applying molecular techniques to problems relevant to the food industry. One area of expertise is in the application of molecular typing techniques to permit rapid… read more

Selected Publications

  • DODD, C.E., 2005. Factors affecting stress response.. In: Understanding pathogen behaviour Virulence, stress response and resistance 1. Woodhead Publishing, Cambridge. 115-124

Current Research

My research has been directed at applying molecular techniques to problems relevant to the food industry. One area of expertise is in the application of molecular typing techniques to permit rapid and sensitive differentiation between strains of a bacterial species, to enable changes in microbial flora in the food processing environments to be studied in detail. One aspect is in providing information for hazard analysis critical control point (HACCP) analyses to establish critical control points (CCP) and validate existing control systems. CCP are typically where cross contamination events occur in a process and identifying such points merely by monitoring counts of microbial hygiene indicators is ineffective, especially in the control of low level pathogens such as Salmonella. My work on tracking the distribution of organisms though a processing plant has proved an effective way of identifying those sites where new strains arise and hence sites of cross contamination and has also highlighted where existing monitoring systems fail. This novel method of investigation has concentrated on enteric pathogens primarily in poultry production and red meat and poultry processing, but has also been validated in the bakery and chill food industry. Recent funding has come from the Food Standards Agency for examining HACCP in pork production and routes of contamination with enteric pathogens in red meat production. A second application of these techniques is in the examination of the population structure of pathogenic bacteria and relating this to source of isolation. Collaboration with Dr Cath Rees has resulted in the development of a novel multiplex primer system for differentiation and toxin typing of Staphylococcus aureus strains (Sharma. N.K., Rees C.E.D., & Dodd, C.E.R. 2000 Development of a single-reaction multiplex PCR toxin typing assay for Staphylococcus aureus strains. Applied and Environmental Microbiology 66, 1347-1353). A further important area of my research addresses the ability of bacteria to survive the stresses encountered in food processing. The work has concentrated on the examination of the rpoS regulon which is responsible for the induction of a specific subset of bacterial genes expressed only under stress conditions. Such factors may be important in preconditioning bacteria to survive subsequently imposed stresses and may have important implications for the food industry. The use of molecular methods has allowed the differences in RpoS in different strains of bacteria to be assessed and coupled with reporter gene systems has enabled the role of RpoS to be examined in realistic food systems. This led to a new hypothesis of bacterial responses to stress the suicide response which changes the perspective of why exponential phase cells are more sensitive to sub-lethal injury (Dodd et al. 1997 Inimical processes: bacterial self-destruction and sub-lethal injury. Trends in Food Science and Technology 8 238-241; Aldsworth, T.G., Sharman R.L. & Dodd, C.E.R. 1999 Bacterial suicide through stress. Cellular and Molecular Life Sciences 56, 378-383). How bacteria behave in real environment compared to their behaviour in laboratory grown conditions is a third area of interest. One approach has been to develop techniques for the detection of bacterial growth in situ in biological matrices and to examine the influence of microenvironments in a matrix on bacterial growth. Initially I developed techniques of cryosectioning, microscopy and antibody-linked probes to examine bacteria in situ in complex solid systems, in conjunction Institute for Food Research, Norwich). More recently the use of fluorescence in situ hybridisation with rRNA directed probes has enabled multi-species detection of bacteria in complex biofilms and food matrices.

Division of Food Sciences

University of Nottingham
Sutton Bonington Campus
Loughborough, Leicestershire LE12 5RD

telephone: +44 (0) 115 951 6141
email: lynne.moseley@nottingham.ac.uk