TILSITER AND CHEDDAR CHEESE

Sr-90 is one of the most important radionuclides concerning radiation exposure of men via ingestion of radioactivity with food. Since the Ch ernobyl accident in 1986 this radioisotope has found again growing int erest because of the deposition of substantial activities in the surro undings of this reactor. This paper describes experiments to determine retention factors for strontium radionuclides during processing milk to Tilsiter and Cheddar cheese. Most of the work was done via determin ing the distribution of the naturally occuring stable strontium in mil k and milk products by atomic absorption spectrometry. In some simulat ion experiments Sr-85 as a tracer had to be used. The strontium retent ion factor of Tilsiter was found to be 7.9. The corresponding value fo r Cheddar cheese was somewhat higher with 9.3 due to a lacking washing procedure of the curd.