The European Commission Joint Research Centre (EC JRC) recently announced the launch of certified reference materials for somatic cell counting in milk. The joint project is international in scale and is the result of a collaborative effort between EC JRC, the International Dairy Federation (IDF), and the International Committee for Animal Recording (ICAR). The aim of the project is to provide a new anchor for better equivalency and traceability in somatic cell counting worldwide.
The reference material is the result of years of collaborative work that began with a feasibility study. The purpose of the study was to investigate how to manufacture homogenous, stable and commutable reference material. It was important to be able to do this large scale. While freeze-dried material is suitable for small-scale production, spray drying appeared to be the best option for large-scale production.
While the project was spearheaded from Europe, it is global in scale. Harrie van den Bijgaart, Manager Innovation & Business Development of Qlip in The Netherlands, led the project. All continents were represented and actively participated in the project group, he said.
Somatic cell counting is a key indicator for udder health in dairy cows and other lactating animals. While it’s certainly not the only indicator, it is the most widely used. Accurate counting is crucial for assuring food hygiene and animal health and welfare, as well as in the frame of raw milk quality regulations. Accurate counts impact regulatory compliance, as well as payment, since high somatic cell counts often lead to penalties and sometimes outright rejection.
To count somatic cells, technicians use routine counters, mostly fluoro-opto-electronic cell counters. Examples are instruments such as Fossomatic, Somascope and Somacount. Control samples are used to make sure the counters are accurate measuring samples for testing.
Counters measure the number of somatic cells in milk, including epithelial cells and leucocytes. The number of leucocytes provides an indication of inflammation. Typically, a direct microscopic method currently serves as reference method whereby somatic cells are counted by hand and eye, explained Van den Bijgaart.
“So it’s visual counting of particles which are fitting the morphological characteristics that are defined in the standard,” he said. “That’s a laborious method. It’s tedious, cumbersome, and it’s subjective because it’s always difficult for an analyst to decide what to count and what not to count.”
“That gives rise to variation, between analysts and between laboratories” he added.
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