Risk factors for Escherichia coli O157 hide contamination of Scottish cattle
This thesis is an investigation into the risk factors for 'Escherichia coli' O157 hide contamination and hide cross-contamination of Scottish cattle at slaughter. In the slaughter processing of cattle, contaminated hides have been identified as one of the major sources of 'E. coli' O157 carcass contamination, which in turn is a significant food safety concern. In order to examine individual animal characteristics, farm management practices, and slaughterhouse features as potential risk factors, multivariable logistic regression analyses were applied to data collected in a study of 256 cattle from 34 farms sent for slaughter to twelve slaughterhouses in Scotland. Data sparsity issues were encountered, and therefore various methods of analyzing such data were explored. Modifiable risk factors for hide contamination and hide cross-contamination were identified, and could provide direction for the future development of 'E. coli' O157 hide contamination reduction strategies.