Anhydrous butterfat reference material CRM 519: certification of triglyceride composition and cholesterol content including homogeneity and stabilitytests

For controlling butterfat purity throughout the European Union using gas ch romatographic triglyceride analysis in combination with triglyceride formul ae (EU reference method) a certified reference fat is needed for calibratio n. After preparation of 1900 ampoules of anhydrous milk fat, the homogeneit y was tested successfully by triglyceride analysis of every 50th sample. Af terwards, long-term stability tests were performed for storage temperatures of -18 degrees C, 4 degrees C, and 20 degrees C by regularly controlling s everal parameters. Within two years, these tests neither exhibited changes in the triglyceride composition or the refractive index, nor were the limit s given for the peroxide value and the content of free fatty acids transgre ssed at any time. In a ring test with thirteen laboratories from eight EU c ountries participating the triglyceride composition of the reference materi al was determined gas chromatographically and after exclusion of outliers c ertified by the Community Bureau of Reference (BCR) as CRM 519.