Department of Animal Science, The University of Tennessee, Knoxville 37996, USA.
J Dairy Sci. 2012 Aug;95(8):4275-9. doi: 10.3168/jds.2011-4881.
The purpose of this study was to evaluate the bulk tank milk (BTM) quality of 9 East Tennessee dairy farms and to determine its relationship with selected quality milk parameters. Bulk tank milk samples (n=1,141) were collected over a 42-mo period (June 2006 through November 2009) from farms, based on their preliminary incubation count (PIC) history. Parameters of BTM quality evaluated in this study included somatic cell count (SCC), standard plate count (SPC), PIC, laboratory pasteurization count (LPC), Staphylococcus spp. count, Streptococcus spp. count, and coliform count. Strong correlations between SPC and Streptococcus spp. counts (0.72) and between SPC and PIC (0.70) were found. However, moderate correlations were seen among other milk quality parameters. In addition, seasonal variations for some milk quality parameters were noted. For example, milk quality parameters such as SCC, SPC, LPC, and coliform count were significantly higher in summer, whereas Streptococcus spp. counts were significantly higher in winter. No seasonal variation in PIC or Staphylococcus spp. counts was observed. Summarizing, results from this investigation showed the importance of using several bacterial counts (SCC, SPC, PIC, LPC, Streptococcus spp. count, Staphylococcus spp. count, and coliform counts) as simultaneous indicators of milk quality.
本研究旨在评估田纳西州东部 9 个奶牛场的牛奶大容量储存罐（BTM）质量，并确定其与选定的优质牛奶参数之间的关系。本研究从农场采集了 1141 份牛奶大容量储存罐样本，采集时间为 2006 年 6 月至 2009 年 11 月，这是基于他们的初步培养计数（PIC）历史。在这项研究中评估的牛奶大容量储存罐质量参数包括体细胞计数（SCC）、标准平板计数（SPC）、PIC、实验室巴氏杀菌计数（LPC）、金黄色葡萄球菌计数、链球菌计数和大肠菌群计数。发现 SPC 与链球菌计数（0.72）之间以及 SPC 与 PIC（0.70）之间存在很强的相关性。然而，其他牛奶质量参数之间存在中度相关性。此外，还注意到一些牛奶质量参数的季节性变化。例如，SCC、SPC、LPC 和大肠菌群计数等牛奶质量参数在夏季显著升高，而链球菌计数在冬季显著升高。未观察到 PIC 或金黄色葡萄球菌计数的季节性变化。综上所述，本研究的结果表明，使用几种细菌计数（SCC、SPC、PIC、LPC、链球菌计数、金黄色葡萄球菌计数和大肠菌群计数）作为牛奶质量的同时指标非常重要。
