Milk has played a major contribution to the human diet in many different countries across the world since the dawn of time. The dairy cow was domesticated over 6000 years ago, she was the object of worship in the Middle East 2000 years before Christ, and milk and milk products are mentioned more than 50 times in the Bible. Milk and dairy products have become a major part of the human diet in many countries. It is not surprising therefore, that over many years considerable attention has been paid to improving the quality of milk. We have worked to improve the yield, the compositional quality and the hygienic quality, and have striven to minimise the level of contaminants which can find access to this, perhaps our most natural, unrefined and highly nutritious foodstuff. The chain of people involved in the milk industry extends from milk production-farmers, veterinarians and farm advisors-through transport to processing-quality controllers, manufacturers-and on to retailers, legislators, nutritionists, dairy educators and consumers. All will be interested in the quality parameters of milk which are reg­ ularly measured for commercial reasons, for trade, for legal requirements and for reasons of nutrition.