European Commission, Joint Research Centre (JRC)

A new CRM for somatic cell count in milk: ERM-BD001

The JRC released ERM®-BD001, a set of two Certified Reference Materials (CRMs) certified for the concentration of somatic cells in milk.

The materials shall be used for calibration and quality control in dairy laboratories operating methods compliant with ISO 13366-1 (reference method based on microscopy) and ISO 13366-2 (routine method based on fluoro-opto-electronic counting). Worldwide, approximately 500 million analyses per year are performed.

Somatic cells are white blood cells naturally occurring in raw cow's milk and comprise all cells with nuclei, i.e. lymphocytes, macrophages, and polymorphonuclear neutrophils and epithelial cells. Somatic cell count (SCC) is an important parameter for hygienic quality of milk and for animal health. An elevated SCC level in milk can serve as an indicator for udder infection (mastitis) of lactating cows and thus points at insufficient hygiene practices on farms. SCC is used for various purposes such as milk payment, checking compliance with regulations, and milk recording for genetic evaluation and farm management. A SCC < 400 000 cells/mL for raw cow's milk has been defined as a quality criterion in Council Directive 92/46/EEC [9] laying down the health rules for production and placing on the market of raw milk, heated milk and milk-based products, and in Regulation (EC) 853/2004 of the European Parliament and of the Council [10], laying down specific hygiene rules for food of animal origin. Raw cow’s milk was converted into milk powder by means of defatting, microfiltration of somatic cells, concentration and spray-drying.

The materials were certified using an interlaboratory comparison study with 32 participating laboratories from 21 countries and 3 continents. Laboratories submitted results from reference method measurements, routine method measurements, or both.

The CRMs represent an integral part of the currently established reference system for somatic cell counting in milk and will enhance the comparability of measurements over time and space.

Further details on ERM®-BD001 can be found in the certificates and the certification report available in our on-line catalogue.