This paper presents a study of some factors that could have an influence on the quality of milk used as raw material in the dairy industry. The research was conducted over a period of 10 months in three milk collection centres located in different geographic regions from northeastern Romania. The analytical methods used were the classic ones, but also modern methods, which gave accurate results in a short time and so, could be easily interpreted. The statistical analysis has shown that other methods with rapid result response, and not standardized yet, were used successfully, because all the values of the statistic factor, Relative Standard Deviation (RSD), are under 1%, that is the limit for a method to be efficient, accepted by the normative.