Interrelations between year season and raw milk hygienic quality indices

The aim of this study was to evaluate milk hygienic quality and to determine a relationship between season of year and raw milk quality indices. The experiment was carried out on 38 samples of milk collected from 80 high–production cows managed in a leading cattle breeding centre in south–west Poland. The analysis comprised total bacteria count, somatic cell count in 1 cm3 of milk, chemical composition assay, i.e. fat and protein content, freezing point determination and test for inhibitory substances. The quality of milk was evaluated instrumentally, and the analysis for inhibitory substances was done using Delwotest assay. Both chemical composition and hygienic quality were within the standard set for the Extra class of raw milk. The season of year significantly influenced the chemical composition of milk and somatic cell count, however, it has no effect on freezing point or total bacteria count.