Correlative analysis of the freezing point and of the microbial content of milk produced by indigenous cows bred in a sub-Carpathian mountain area

Introduction: Mountainous geo-climatic conditions exert major beneficial influences on the health and welfare of lactating cows and by default on the compositional and microbiological parameters of milk and also on the sensory characteristics of traditional milk products from those areas. Aims: Through research in this paper we propose to analyze new criteria for evaluation of freshness and health of milk obtained in conditions of sub-Carpathian mountain areas, based on the freezing point - TNG (total number of germs) correlation. Materials and methods: During a time of 2 years there were investigated physicochemical (analyzer Ekomilk M) and microbiological (with automatic system Soleris) milk samples commodity from the mountain area Gurghiu Valley. Milk samples were taken from cows of indigenous breed belonging to traditional households (n=650), to microfarms (n=11) and commercial farms (n=2). From each source were analyzed 10 samples of milk each month, having a total of 240 sample/lot or 720 per entire amount of processed milk. According to the followed objectives, the interpretations were mainly focused on development of the freezing point and of TNG. Statistical analysis was focused on the correlations between these parameters and seasonal influences. Results: The evolution of the freezing point was characterized by insignificant statistically differences (p = 0.071) and very close mean values (between - 0.5660C and - 0.5650 C) among 3 samples and by significant statistically differences (p = 0.0001) between winter seasons with the highest values (- 0.5600C) and autumn, with the lowest levels (-0.5710C). Regarding the evolution of the microbial content of raw milk is important to note the oscillations of TNG, which are influenced by variables: sampled and season. At the level of the lot, TNG has reached higher levels (71.210 CFU/mL) in the case of milk from individual farms. The evolution of the seasonal influences revealed minimal levels (64.300 CFU/mL) in summer and the maximum levels in the autumn (76.720 CFU/mL), with statistically significant differences (p = 0.0001). Conclusions: We believe that seasonal patterns, with statistically significant differences, marked by significant decreases of the freezing point during autumn, associated with minimum values of TNG in summer and maximal in autumn, support the implementation of the freezing point - TNG correlation in the evaluation of the freshness and health of milk obtained in mountainous areas