Authors: K. Knappstein, N. Roth, B.A. Slaghuis, R.T. Ferweda-van Zonneveld
The cleaning of udder and teats before milking contributes to the image of
hygienic food production. Teat and udder surfaces belong to the main sources
of bacteria in raw milk. Therefore appropriate cleaning procedures are
necessary to reduce the microbial contamination of raw milk. As part of
workpackage 6 within the European project "Implications of the Introduction of
Automatic Milking on Dairy Farms" a protocol was developed to evaluate
mechanised teat cleaning devices that are in operation in automatic milking
systems.
The evaluation of teat cleaning procedures will be based on a combination of
four methods: visual inspection, sediment test on teat swabs and determination
of total bacterial counts (TBC) and ATP in teat swabs. The results of visual
inspection are largely dependent on the evaluating person and also vary within
testing person when the same material is evaluated repeatedly. Nevertheless,
visual inspection and sediment tests are suitable to determine teat
cleanliness if cleanliness is defined as the absence of visible contamination
with dirt and/or manure. For cleaned teats identical scoring by the two
methods was determined in 95.8 % (n=96). The total impression of udder
cleanliness seemed to be mainly influenced by the status of the udder basis.
By comparison of TBC and ATP in teat swabs taken before and after teat
cleaning a differentiation of cleaning efficiency of manual teat cleaning
methods was possible. By wet cleaning with subsequent drying a better teat
cleaning effect was achieved: the reduction of TBC in Log10 units was 1.50
(wet cleaning with subsequent drying of the udder) versus 1.11 (dry cleaning),
the reduction of ATP in Log10 RLU was 1.26 versus 0.56. The efficiency of
manual cleaning methods will serve as a reference for the following evaluation
of mechanised cleaning devices applied in practice during the second part of
the study.
Another approach for the evaluation of teat cleaning efficiency was based on
artificial contamination of teats with cobalt and subsequent determination of
its carry over into milk, but could not be validated yet. The loss of cobalt
after application on teats was high. Although carry over from teats and from
teat cleaning devices into milk was found, no difference between cleaning and
no cleaning of teats could be determined when the method was applied on an
automatic milking system. Additional experiments are necessary to validate the
cobalt method.
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© Animal Sciences Group -
Wageningen UR. Last update:
20-02-2008 10:03. |
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