B12003: Investigation of the effectiveness of pre-milking teat cleaning regimes

Study Duration: October 2002 to November 2004

Contractor: University of Wolverhampton

Increasing competition in the market place and the demands of health and hygiene conscious consumers require very high standards of hygiene at all stages in the production of diary products. The application of Hazard Analysis Critical Control Point (HACCP) principles to the production of such products identifies the microbiological quality of the milk as a crucial factor and clearly for this the milk must be produced in a clean environment, from non-infected udders, using practices to minimise bacterial contamination.

A number of factors contribute to the exposure of the teats to pathogenic organisms. These include housing facilities, management practices, parlour type/design, milking practices, cow stress levels, type of bedding, whether housed and type of housing. In order to control the level of contamination of the teats and therefore the milk, these factors must be effectively managed in conjunction with the application of effective decontamination procedures.

Hygienic teat management means that the teats should be clean with minimal bacterial load and this can be achieved by a combination of appropriate housing, bedding, housing cleaning and teat cleaning practices. The use of pre-milking cleaning may be an essential part of the management strategy.

The project will identify and assess pre-milking teat cleaning practices in current use and investigate the nature of the decontamination problem in terms of levels and types of micro-organisms.

Pre-milking teat treatments in current use will be assessed in a split herd design to assess the efficacy of the cleaning techniques by teat swabbing before and after treatment , and analysis by Total Viable Count and ATP bioluminescence. Trials will be conducted in triplicate farms of two parlour types over a 12 week period during the summer (low/dry soiling) and winter (high/heavy) soiling. The treatments will be selected on the basis of the results of a questionnaire sent to farmers to establish current pre-milking cleaning methods. The controlled studies will be planned in detail on the basis of initial trials to establish the levels and types of micro-organisms on a variety of farms selected to give a range of parlour types, total milk bacterial counts, geographical location, mastitis incidence, herd size and soil type. Analysis of the results of the controlled studies will allow the production of best practice guidelines.

Hazard analysis identifies teat cleanliness as a critical control point for the reduction of bacteria in milk. A number of factors contribute to the exposure of cows� teats to pathogenic organisms, including animal health and nutrition, housing and feeding facilities, parlour design, milking procedures and herd management techniques. This study was undertaken to assess the effectiveness of pre-milking teat cleaning regimes in reducing microbial loading.

The study found that microbial loading on teats was variable and independent of visual cleanliness so it is therefore essential to clean all cow teats, not just those with visibly soiled teats, before milking. In order to achieve the optimum benefits, the cleaning regime must be applied carefully as poorly applied pre-milking teat cleaning resulted in the spread of bacteria between cows and could potentially increase the bacterial load available to enter the milk supply. Cleaning only removed a proportion of the bacteria present so farms with a high initial teat loading remain relatively high after treatment, emphasising that good overall herd management is important to help reduce the initial levels. The questionnaire and microbiological survey identified a number of management practices on certain farms that may increase the risk of bacterial contamination, including using the same cleaning towels on more than one cow and animal housing conditions.

The control trials found that a cleaning regime involving a disinfectant wash and dry to be most effective at reducing bacteria levels, while dry wiping was consistently the least effective technique in the trial. The wash and dry cleaning regime was more effective than a dip and dry regime when the same chemical was used. Where the time available to apply a wash and dry cleaning regime was limited, for example in a rotary parlour, medicated teat wipes may be the most appropriate regime.

By identifying key actions that could reduce the potential bacterial contamination of milk from the cow�s teat during milking, this research will benefit the consumer by improving the microbiological quality of raw milk and therefore improving food safety. The findings may be used to develop practical advice suitable for use by dairy farmers to assist them in the selection of a practical pre-milking teat cleaning regime to effectively reduce the microbial load on teats.

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)

Contact: For any enquiries concerning this research project, please contact the relevant Programme contact or email: science@foodstandards.gsi.gov.uk