Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

Redefinition of acceptable milk quality

This work package and its results give an overview of the work done including definitions of normal and abnormal milk, suggestions for reference methods, and tests of AMS models according to these requirements. The general conditions of hygiene in milk production in the EU are defined by the Commission Directive 89/362/EEC (1989) but not all elements apply to automatic milking. The following text is proposed to be included in the coming EU Hygiene Directive:

"Milking must be carried out hygienically ensuring in particular: - that milk from an animal is checked for abnormalities by the milker or a method achieving similar results and that only normal milk is used for human consumption and that abnormal, milk with a withholding period, and undesirable milk are excluded".

The definition of abnormal milk caused by clinical mastitis is proposed to be based on the homogeneity of the milk and not on the colour since the colour of the milk changes with breed, stage of lactation, feedstuffs etc. The reference method is suggested as filtration of the milk through a filter with a pore size of 0.1 mm, and milk where clots are clearly visible in such a filter is then defined as being abnormal. Incidences of watery and yellowish milk may or may not be detected by this method. The current AMS models have systems to produce alarm lists of cows that should be checked for abnormalities in their milk and at present the systems are not intended for automatic diversion of milk. Five different AMS-models were tested in six herds. The sensitivities for detection of abnormal milk in the six herds varied from 13 to 50% when calculated for the actual milking, from 22 to 100% for the test days, and from 43 to 100% when calculated for the previous week. Specificities for the same time periods were found to be 87-100%, 85-100%, and 35-100%, respectively. The sensitivities and specificities are generally too low for automatic diversion of abnormal milk and it seems as if most of the models could benefit from application of more sophisticated algorithms or measurements more directly related to the definition of abnormal milk.

Reported by

Danish Institute of Agricultural Sciences
Research Centre Foulum PB 50
8830 Tjele
Denmark