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Listen to this siteTuesday 26 July 2005
This research project will provide a general overview of current thinning practices on UK broiler farms and provide recommendations suitable for guidance on thinning procedures.
Study Duration : November 2004 to October 2006
Contractor : University of Bristol
Thinning is the removal of a portion of the flock before depopulation. It is a common practice throughout the UK poultry industry, allowing farmers to maximise the use of space for rearing birds while meeting the necessary welfare requirements for stocking density and consumer demands for birds of different sizes.
However, by its nature, thinning is a breach of biosecurity. Background information from Food Standards Agency project 'Studies to identify critical control points for infection of live birds or contamination of poultry carcasses with campylobacter and salmonella species', DEFRA's project 'Epidemiological studies and development of practical control measures for campylobacter in broiler flocks' and data from international and UK companies have indicated that the thinning process introduces and/or exacerbates campylobacter infection of the remaining flock.
The project aims to collect advice on Code of Practices (COPs) and Standard Operating Procedures (SOPs) from major poultry companies, retailers and auditing organisations. A visual audit of company thinning procedures will be compared against written protocols and testing of flocks and depopulation equipment for campylobacter in order to identify the areas of risk. The study will produce recommendations suitable for the production of guidance material and suggest any appropriate intervention measures.
Previous FSA-funded work has indicated that ‘thinning’ of broiler flocks (depopulation of the poultry house over a period of days) is associated with an increase in prevalence of Campylobacter infection in those birds left after the initial period of catching. This current project was intended to examine this hypothesis by undertaking a detailed review of current industry practices and procedures coupled with a programme of microbiological tests for Campylobacter . The overall objective of the work was to produce recommendations suitable for the production of guidance material for thinning procedures and suggest any suitable intervention measures.
This project demonstrated that thinning flocks can be a risk factor for Campylobacter and supports the need for industry guidance to minimise infection at the time of thinning. A reduction in Campylobacter levels on farms tested between the first and second year of the study coincided with heightened biosecurity, probably as a result of increased awareness of avian influenza by the industry. The findings support the Agency’s strategy to promote good biosecurity.
A total of 51 farm visits were made between June – October 2005 and February – September 2006 to collect information on hygiene and biosecurity practices and procedures, and to collect samples to test for the presence of Campylobacter .
All flocks which were negative before thin (60%) became positive after thinning, mostly within 2 to 6 days. Examination of culled birds indicated rapid spread through the flock with high numbers of Campylobacter in the birds’ caeca. However, two flocks were found to be negative at slaughter despite some birds being colonised with Campylobacter shortly after thinning.
Campylobacter was also isolated from poultry-catching crews: on hands, shoes and their vehicles, as well as from transport lorries, crates and modules. This indicates that vehicles, equipment and personnel entering and leaving the farm before and after the thinning process are potential areas of risk. In many cases these isolates were indistinguishable from the Campylobacter strain subsequently colonising the flock.
Information was collected on farm thinning practices by interviews and completion of a detailed questionnaire. Following a review of the farm audit findings, a number of recommendations were made:
Unfortunately, due to the lack of Campylobacter negative flocks following thin, a statistical analysis to correlate the incidence of Campylobacter with practices and procedures on the farm during thinning was not possible. However, there was some evidence that hand sanitisation, vehicle disinfection and positioning of modules were associated with a reduced incidence of Campylobacter immediately prior to thinning.
In terms of possible interventions, only water treatment appeared to be significantly correlated with a reduction in Campylobacter at thin. Given the potential benefits that such an intervention could provide, it was recommended that this issue be explored further.
The findings of this study will enable the Agency to identify the key practices that help reduce the introduction and spread of Campylobacter at the time of thinning, to produce recommendations regarding guidance material for thinning procedures and to suggest any suitable intervention measures. The findings have also helped inform a biosecurity training programme undertaken in 2006 for poultry-catchers.
The final report is available from the Agency’s Information Centre.
To obtain a copy, please contact the Enquiry Desk, Information Services, Food Standards Agency (tel: 020 7276 8181/8182 or email:
infocentre@foodstandards.gsi.gov.uk
)
For any enquiries concerning this research project, please contact the relevant Programme contact or email: science@foodstandards.gsi.gov.uk
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