对云南省不同来源生鲜乳品质的比较分析

Comparative Analysis of the Quality of Raw Milk from Different Sources in Yunnan Province

本试验旨在通过对不同来源生鲜乳的相关指标进行测定和比较分析,评价其品质,为地方奶牛养殖业的发展提供参考依据。采集2017-2020年云南省养殖专业合作社、乳品公司养殖场、收购站和机械化挤奶站4种来源的生鲜乳共661个样品,采用国家标准方法测定其相关指标,用SPSS 22.0统计软件做单因素方差分析。结果显示,2017-2020年不同来源生鲜乳中的碱类均为阴性,皮革水解物均未检出;冰点在-0.500~-0.536℃之间,相对密度1.029~1.031g/mL之间,且不同来源间无显著差异(P>0.05)。4种来源的生鲜乳蛋白质和脂肪含量均达到国标要求,2017年,来源于养殖专业合作社、乳品公司养殖场和收购站的蛋白质和脂肪含量显著高于机械化挤奶站(P<0.05);2018年,来源于乳品公司养殖场的生鲜乳蛋白质含量显著高于其他3种来源(P<0.05),来源于乳品公司养殖场的生鲜乳脂肪含量显著高于收购站来源(P<0.05);2020年,来源于乳品公司养殖场的生鲜乳蛋白质含量显著高于其他3种来源(P<0.05)。2017和2020年,来源于收购站的生鲜乳杂质度显著高于其他3种来源(P<0.05),而2018年4种来源间差异不显著(P>0.05)。2017年,来源于乳品公司养殖场的生鲜乳体细胞数和菌落总数显著低于其他3种来源(P<0.05);2018和2020年,来源于收购站的生鲜乳菌落总数显著高于其他3种来源(P<0.05),机械化挤奶站生鲜乳体细胞数显著高于其他3种来源(P<0.05)。总体可见,乳品公司养殖场生鲜乳中的蛋白质、脂肪含量优于其他3种来源,机械化挤奶站的生鲜乳中杂质度和菌落总数优于其他3种来源,提示奶牛养殖应大力发展标准化养殖和机械化挤奶。

This experiment aims, by measuring and comparing the relevant indicators of fresh milk from different sources, to evaluate its quality and provide a reference for the development of local dairy cattle breeding. A total of 661 samples of raw milk were collected from 4 sources, i.e., breeding cooperatives of Yunnan Province, dairy company farms, purchase stations and mechanized milking stations from 2017 to 2020. National standard methods were used to determine their relevant indicators, and SPSS 22.0 statistical software was employed to conduct ANOVA. As a result, the alkalis of different sources of fresh milk from 2017 to 2020 were all negative, and no leather hydrolysates were detected;the freezing point ranged from-0.500℃ to-0.536℃, the relative density was between 1.029 ~ 1.031 g/mL and no significant difference was found between milk from different sources(P>0.05).The protein and fat content of raw milk from the 4 sources reached the national standard. In 2017, the protein and fat contents from breeding cooperatives, dairy company farms and purchase stations were significantly higher than that from mechanized milking stations(P<0.05). In 2018, the protein content of fresh milk from dairy company farms was significantly higher than that of the other three sources(P<0.05), the fat content of fresh milk from dairy company farms was significantly higher than that from purchase stations(P<0.05). In 2020, the protein content of raw milk from dairy farms was significantly higher than the other three sources(P<0.05). In 2017 and 2020, the impurity in raw milk from the purchase station significantly exceeded that from the other three sources(P<0.05),while the difference between the four sources in 2018 was not significant(P>0.05). In 2017, the total number of somatic cells and bacterial colonies in fresh milk from dairy farms was significantly less than that from the other three sources(P<0.05);in 2018 and 2020, fresh milk from purchase stations had a significantly greater total number of bacterial colonies than that from the other 3 sources(P<0.05), the somatic cell count in fresh milk from mechanized milking stations were significantly more than those from the other 3 sources(P<0.05). It can be totally seen that the protein and fat contents of fresh milk from dairy farms were better than those from the other three sources, fresh milk from mechanized milking stations achieved better impurity and less total number of bacterial colonies than those of the other three sources, indicating standardized breeding and mechanized milking should be preferentially developed.