Physicochemical and microbiological quality of bovine milk from Vale do Taquari in Rio Grande do Sul, Brazil

Abstract The goal of the present study was to verify the quality of refrigerated raw milk from dairy properties and also of refrigerated raw milk, pasteurized and Ultra High Temperature (UHT) milk from industries in Vale do Taquari in Rio Grande do Sul, Brazil. Physicochemical, microbiological and milk composition analysis were carried out, as established by legislation, in addition to total and thermotolerant coliforms and psychrotrophic counts in the three types of milk and mesophiles count in pasteurized milk and UHT milk from the industries. The collections took place in two industries and 33 dairy properties. Regarding the properties, two (6%) had milk with acidity above that established by legislation and three (9%) had milk with a total bacterial count (TBC) above the established. The milk from industry 1 presented acidity, TBC and density out of the established standards. The two industries and 53.2% of the properties had milk with somatic cell counts (SCC) above that determined by legislation. The milk from the industries showed higher amounts of SCC, TBC, psychrotrophic and total and thermotolerant coliforms than the milk from the dairy properties, and the milk from industry 1 showed higher amounts than the industry 2, in the microbiological parameters.

摘要
本研究旨在验证巴西南大河州塔夸里谷（Vale do Taquari）地区奶牛牧场的冷藏生鲜乳，以及当地乳制品企业生产的冷藏生鲜乳、巴氏杀菌乳与超高温灭菌（Ultra High Temperature, UHT）乳的品质。本研究依照现行法规标准，开展了乳样的理化、微生物及乳成分分析；同时针对三类乳样品检测了总大肠菌群、耐热大肠菌群与嗜冷菌计数，并针对企业生产的巴氏杀菌乳和UHT乳额外检测了嗜中温菌计数。
本次采样共覆盖2家乳制品加工企业与33家奶牛牧场。针对牧场生鲜乳样品，共有2家（占比6%）的乳样酸度超出法规限定标准，另有3家（占比9%）的乳样总细菌数（Total Bacterial Count, TBC）不符合规定要求。1号企业的乳样在酸度、TBC与密度三项指标上均未达标。
参与本次研究的2家企业与53.2%的牧场，其乳样的体细胞数（Somatic Cell Count, SCC）均超出法规限定标准。在微生物学参数层面，企业生产的乳样在体细胞数、TBC、嗜冷菌、总大肠菌群与耐热大肠菌群的含量上均高于牧场生鲜乳；其中1号企业的乳样各项微生物指标水平均高于2号企业。