Chemical-microbiological quality parameters of raw cow milk

Abstract

This paper is based on investigation of chemical and hygiene parameters of the quality of cow raw milk. Samples were collected on 10 collection spots of the dairy firm "Imlek", in 4 identical time intervals in the period of one month (20.06.2005.-20.07.2005.) in municipality of Gornji Milanovac, and research was carried out in the laboratory of "Imlek" in Čačak. Differences in chemical composition and hygienic quality of milk were analyzed, and slight variability was established between collection spots. Average content of milk fat was 3,89%, protein 3,20%, and dry matter without fat 8,56%. It was established that in regard to protein content there is significant and very significant statistical difference between collection spots. This is consequence of different nutrition, focus is on introduction of protein enriched feeds into nutrition of cows. High variability of number of micro organisms is consequence of inadequate, non-standardized obtaining (milking) and storing of raw milk. Average number of micro-organisms was 844.875/ml, and it varied from 112.000–5.000.000/ml. Average somatic cell count was 357.850/ml. Variance analysis determined that collection spots had statistically highly significant effect (P (lt) 0.01) only on protein content, whereas their influence on content of fat, dry matter without fat, number of microorganisms and somatic cell count wasn't significant (P>0.05). Individual testing (LSD test) established that milk collected from 7th collection spot had significantly higher protein content compared to other collection spots, which indicated that dairy heads of cattle consumed higher quantity of feeds rich on proteins and had better balanced diet in regard to ratio of energy and protein.

Rad je zasnovan na ispitivanju hemijskih i higijenskih parametara kvaliteta sirovog mleka. Uzimanje uzoraka je vršeno na 10 "Imlek"-ovih sabirnih mesta u 4 jednaka vremenska razmaka u periodu od mesec dana (20.06.2005.-20.07.2005.godine) u opštini Gornji Milanovac, a ispitivanje je izvršeno u laboratoriji "Imlek"-a u Čačku. Analizirane su razlike u hemijskom sastavu i higijenskom kvalitetu mleka, pri čemu su utvrđene male varijabilnosti između sabirnih mesta. Prosečan sadržaj mlečne masti iznosio je 3,89%, proteina 3,20%, a suve materije bez masti 8,56%. Utvrđeno je da kod sadržaja proteina postoji značajna i vrlo značajna statistička razlika između sabirnih mesta. To je posledica različite ishrane, pri čemu se daje akcenat na uvođenje u ishranu proteinski bogatih hraniva. Ispitivanje hemijskog sastava i mikrobiološke ispravnosti, koje je vršeno kod proizvođača AD "Imlek"-a, pokazalo je izvestan pomak u poboljšavanju higijenskog kvaliteta sirovog mleka. Visoka varijabilnost kod broja mikroorganizama posledica je neadekvatnog, nestandardizovanog dobijanja (muže) i čuvanja sirovog mleka. Prosečan broj mikroorganizama je iznosio 844.875/ml, a kretao se od 112.000-5.000.000/ml. Prosečan broj somatskih ćelija je 357.850/ml.