Acta Univ Latv (2007) 723: 171–180

Influence of chemical preservatives on the quality and composition indices of raw milk samples

Abstract

The experiment was conducted to assess the feasibility of sodium azide, hydrogen peroxide, bronopol, azidiol, boric acid and potassium sorbate as milk preservatives before estimation of the indicators of the content and quality of raw milk using instrumental methods. The milk samples were collected from fresh bulked milk of the dairy farm in Riga District. Milk samples were stored at 4°C and 20°C. Untreated milk samples were considered as control samples and were tested against samples treated with 0.02 % sodium azide, 0.06 % hydrogen peroxide, 0.04 % bronopol, 0.4 % azidiol, 1.0 % boric acid and 0.5 % potassium sorbate. Microbiological and chemical parameters (total bacteria count, fat and protein content, somatic cell count) of raw milk samples were measured in all samples just before preservation and then regularly after specific time interval. The results showed that the most suitable preservatives for storing milk before the estimation of the indicators of the content and quality of raw milk by using instrumental methods are bronopol, sodium azide and azidiol. To ensure stable milk quality starting from the time of sample collection till the analysis, it is advisable to preserve the samples with the above-mentioned compounds and storage at 4°C not longer than 96 hours.