Seasonal variation in the quality parameters of milk from an extensive, small family farm

This research aimed to determine the hygienic quality, physicochemical properties and technological suitability of milk obtained in an extensive, small family farm in western Poland in the spring-summer (grazing) and autumn-winter (indoor) seasons. The farm was operated in the traditional manner where animals spend 7/24 on the pasture in the spring-summer season. The study was performed on forty-eight samples of bulk tank milk collected once a week over one year from 17 cows of the old local Polish black and white lowland breed. Milk was tested for somatic cell count, total bacterial count, basic composition, density, vitamin C content, rennet coagulation time, pH and colour in the CIE L*a*b* system. In the autumn-winter season, a higher somatic cell count, higher protein, fat and lactose levels, longer coagulation time and lower colour parameter a* values were found compared with the spring-summer period. However, no differences as regards the colour parameters L* and b* and vitamin C content were observed between the seasons. Highly significant negative correlations between the colour of the milk and the total bacterial count and somatic cell count were found (P ≤ 0.01). High somatic cells count in studied milk highlights that mastitis and milking hygiene are still a challenging task in small family farms.