• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Applied and Environmental Microbiology >Persistence of Mycobacterium paratuberculosis during Manufacture and Ripening of Cheddar Cheese
【24h】

Persistence of Mycobacterium paratuberculosis during Manufacture and Ripening of Cheddar Cheese

机译：切达干酪生产和成熟过程中副结核分枝杆菌的持久性

获取原文
       
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Model Cheddar cheeses were prepared from pasteurized milk artificially contaminated with high 104 to 105 CFU/ml) and low (101 to 102 CFU/ml) inocula of three different Mycobacterium paratuberculosis strains. A reference strain, NCTC 8578, and two strains (806PSS and 796PSS) previously isolated from pasteurized milk for retail sale were investigated in this study. The manufactured Cheddar cheeses were similar in pH, salt, moisture, and fat composition to commercial Cheddar. The survival of M. paratuberculosis cells was monitored over a 27-week ripening period by plating homogenized cheese samples onto HEYM agar medium supplemented with the antibiotics vancomycin, amphotericin B, and nalidixic acid without a decontamination step. A concentration effect was observed in M. paratuberculosis numbers between the inoculated milk and the 1-day old cheeses for each strain. For all manufactured cheeses, a slow gradual decrease in M. paratuberculosis CFU in cheese was observed over the ripening period. In all cases where high levels (>3.6 log10) of M. paratuberculosis were present in 1-day cheeses, the organism was culturable after the 27-week ripening period. The D values calculated for strains 806PSS, 796PSS, and NCTC 8578 were 107, 96, and 90 days, respectively. At low levels of contamination, M. paratuberculosis was only culturable from 27-week-old cheese spiked with strain 806PSS. M. paratuberculosis was recovered from the whey fraction in 10 of the 12 manufactured cheeses. Up to 4% of the initial M. paratuberculosis load was recovered in the culture-positive whey fractions at either the high or low initial inoculum.
机译：切达干酪奶酪的模型是由人工污染的巴氏杀菌牛奶制成的，这些牛奶经三种不同的副结核分枝杆菌菌株的高104-105 CFU / ml和低（101-102 CFU / ml）接种。在此研究中，研究了参考菌株NCTC 8578和先前从巴氏灭菌牛奶中零售的两种菌株（806PSS和796PSS）。制成的切达干酪的pH，盐，水分和脂肪成分与市售切达干酪相似。通过将均质的奶酪样品铺板到补充有万古霉素，两性霉素B和萘啶酸的抗生素的HEYM琼脂培养基上，无需进行去污步骤，即可监测成熟结核分枝杆菌细胞在27周成熟期间的存活率。对于每种菌株，在接种的牛奶和1天龄的奶酪之间观察到副结核分枝杆菌数量的集中效应。对于所有制成的奶酪，在成熟期间均观察到奶酪中副结核分枝杆菌CFU缓慢缓慢下降。在1天的奶酪中存在高水平（> 3.6 log10）副结核分枝杆菌的所有情况下，在经过27周的成熟期后即可培养该微生物。计算的806PSS，796PSS和NCTC 8578菌株的D值分别为107、96和90天。在低污染水平下，副结核分枝杆菌只能从掺有806PSS菌株的27周龄奶酪中培养。从12个制造的奶酪中的10个的乳清级分中回收了副结核分枝杆菌。在高或低初始接种量下，培养阳性乳清级分可回收高达4％的初始副结核分枝杆菌负荷。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号