Fate of Staphylococcus aureus in cheese treated by ultrahigh pressure homogenization and high hydrostatic pressure.
Fate of Staphylococcus aureus in cheese treated by ultrahigh pressure homogenization and high hydrostatic pressure.
复制标题
超高压均质和高静水压处理奶酪中金黄色葡萄球菌的命运。
DOI：
10.3168/jds.s0022-0302(06)72502-4
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发表时间：
2006
影响因子：
3.5
通讯作者：
B. Guamis
中科院分区：
文献类型：
--
作者：
T. López;W. Briñez;A. Roig;B. Guamis
我们评估了在奶酪制作前对含有金黄色葡萄球菌CECT 976的牛奶进行高压均质化（UHPH）处理的影响，以及对奶酪进行进一步高静水压（HHP）处理的益处。葡萄球菌的进化还评估了在8 ℃下储存30天期间的金黄色葡萄球菌计数和葡萄球菌肠毒素的形成。牛奶中含有约7.3 log（10）cfu/mL的葡萄球菌。使用2阀UHPH机器对金黄色葡萄球菌进行加压，在主阀和次阀分别施加330和30 MPa。测定6和20 ℃的牛奶入口温度（T（in））。牛奶被用来精心制作软凝奶酪（UHPH奶酪），其中一些还提交了10分钟的HHP处理的400 MPa在20摄氏度（UHPH+HHP奶酪）。葡萄球菌的数量金黄色葡萄球菌在第1天（生产后24小时或HHP处理后立即）以及在8摄氏度下成熟2、15和30天后进行测量。未加压处理的对照奶酪的计数约为8.5 log（10）cfu/g，显示在储存期间没有显著降低。在由UHPH处理过的牛奶制成的奶酪中，在6摄氏度的温度下，葡萄球菌的数量。金黄色葡萄球菌在第1天为5.0 +/- 0.3 log（10）cfu/g;在第15天显著下降至2.8 +/- 0.2 log（10）cfu/g，并且在储存30天后低于检测限（1 log（10）cfu/g）。使用额外的HHP处理具有协同效应，从第1天起减少量增加至7.0 +/- 0.3 log（10）cfu/g。然而，对于6摄氏度T（in）样品中的UHPH和UHPH+HHP奶酪，活葡萄球菌。金黄色葡萄球菌细胞仍被回收。对于20 ℃ T（in）组的样品，葡萄球菌完全灭活。UHPH和UHPH+HHP干酪在贮藏15 d后均达到金黄色。在对照组中发现葡萄球菌肠毒素，但在UHPH或UHPH+HHP处理的样品中未发现。这项研究显示了一种新的方法，显着提高奶酪的安全性，通过使用UHPH或其与HHP的组合。
We evaluated the influence of ultrahigh pressure homogenization (UHPH) treatment applied to milk containing Staphylococcus aureus CECT 976 before cheese making, and the benefit of applying a further high hydrostatic pressure (HHP) treatment to cheese. The evolution of Staph. aureus counts during 30 d of storage at 8 degrees C and the formation of staphylococcal enterotoxins were also assessed. Milk containing approximately 7.3 log(10) cfu/mL of Staph. aureus was pressurized using a 2-valve UHPH machine, applying 330 and 30 MPa at the primary and the secondary homogenizing valves, respectively. Milk inlet temperatures (T(in)) of 6 and 20 degrees C were assayed. Milk was used to elaborate soft-curd cheeses (UHPH cheese), some of which were additionally submitted to 10-min HHP treatments of 400 MPa at 20 degrees C (UHPH+HHP cheese). Counts of Staph. aureus were measured on d 1 (24 h after manufacture or immediately after HHP treatment) and after 2, 15, and 30 d of ripening at 8 degrees C. Counts of control cheeses not pressure-treated were approximately 8.5 log(10) cfu/g showing no significant decreases during storage. In cheeses made from UHPH treated milk at T(in) of 6 degrees C, counts of Staph. aureus were 5.0 +/- 0.3 log(10) cfu/g at d 1; they decreased significantly to 2.8 +/- 0.2 log(10) cfu/g on d 15, and were below the detection limit (1 log(10) cfu/g) after 30 d of storage. The use of an additional HHP treatment had a synergistic effect, increasing reductions up to 7.0 +/- 0.3 log(10) cfu/g from d 1. However, for both UHPH and UHPH+HHP cheeses in the 6 degrees C T(in) samples, viable Staph. aureus cells were still recovered. For samples of the 20 degrees C T(in) group, complete inactivation of Staph. aureus was reached after 15 d of storage for both UHPH and UHPH+HHP cheese. Staphylococcal enterotoxins were found in controls but not in UHPH or UHPH+HHP treated samples. This study shows a new approach for significantly improving cheese safety by means of using UHPH or its combination with HHP.