LAUSR

The aim of the study was to examine the contents of nitrates and nitrites in raw beef coming from cattle of the Polish Holstein-Friesian breed, black-and-white type, originating from different parts of Poland. The research material comprised semitendinosus and longissimus thoracis muscles obtained from 176 heads of cattle. The content of nitrites in the examined muscles ranged from 0.6 to 13.3 mg kg–1 in rump muscles and from 0.8 to 13.7 mg kg–1 in muscles of the back. The most samples were characterised by the presence of nitrites in the range from 1 to 5 mg kg–1, and the least samples from 11 to 14 mg kg–1. The contents of nitrates were significantly higher, ranging from 10.2 to 73.5 mg kg–1 in the semitendinosus muscle and from 10.4 to 74.3 mg kg–1 in the thoracis longissimus muscle. Such and higher level of contamination may be the cause of meat discolouration after heat treatment despite the absence of curing ingredients. It is necessary to continuously monitor the concentration of nitrates in raw materials, water and feed to ensure the complete safety of food of animal origin.