Müller H E
Zentralbl Bakteriol B. 1979 May;168(3-4):367-76.
In applying S. mendoza the following four liquid media were tested as to whether they can be used as enrichment broths for salmonellae in milk powder: phosphate buffered water, correspondingly buffered peptone broth, tetrathionate and selenite lactose broth. The yield of salmonellae in these tests is largely independent of the starting pH value of the prepared milk suspension which was varied between 5.8 and 8.2 (Fig. 1). In water the pH dropped within 24 hours (Fig. 2), in peptone and tetrathionate broth within 48 hours down to figures between 4.1 and 4.4 (Fig. 3 and 4), in selenite broth final figures of pH 5.7 were not attained before the lapse of 6 days (Fig. 5). The absolutely highest germ figures were observed in selenite broth. Quite in general the bacteria figure maximum was not attained until the 3rd--5th day, whereupon the germ figures dropped again. In peptone broth the introduced salmonellae were recovered in 73% of all cases after the lapse of 24 hours. Also in tetrathionate the success quota was about 73%, but part of it (8%) did not increase until a lapse of more than 72 hours incubation time, although the pH had already become strongly acid some days previously. In water the introduced salmonellae were traced only in 67%, in selenite broth even only in 61%. Also the time until the first detection increased a little in these media (Table 1). The period during which salmonellae were traceable was equally highest in peptone broth being 57% relative to the complete testing period (tetrathionate: 55%, water: 51%, selenite: 39% (Table 1). This permits the conclusion that peptone broth is the best preenrichment medium in which salmonellae may become traceable after a lapse of approx. 24 hours. Not considerably more unfavourable is the tetrathionate broth which so far had been considered as an exclusive selectivity medium. In this context it is, however, necessary to face the possibility that predamaged salmonellae do not begin to increase until the end of some days incubation and even at a strongly acid pH.
在应用门多萨沙门氏菌时，对以下四种液体培养基进行了测试，以确定它们是否可用作奶粉中沙门氏菌的增菌肉汤：磷酸盐缓冲水、相应缓冲的蛋白胨肉汤、四硫磺酸盐肉汤和亚硒酸盐乳糖肉汤。在这些测试中，沙门氏菌的回收率在很大程度上与制备的牛奶悬浮液的起始pH值无关，该pH值在5.8至8.2之间变化（图1）。在水中，pH值在24小时内下降（图2），在蛋白胨肉汤和四硫磺酸盐肉汤中，在48小时内下降至4.1至4.4之间（图3和图4），在亚硒酸盐肉汤中，直到6天后才达到最终pH值5.7（图5）。在亚硒酸盐肉汤中观察到的细菌数量绝对最高。一般来说，细菌数量最大值直到第3 - 5天才达到，随后细菌数量再次下降。在蛋白胨肉汤中，接种的沙门氏菌在24小时后，在所有案例中有73%被回收。在四硫磺酸盐肉汤中成功率也约为73%，但其中一部分（8%）直到培养72小时以上才增加，尽管几天前pH值已经变得很强酸性。在水中，接种的沙门氏菌仅在67%的案例中被追踪到，在亚硒酸盐肉汤中甚至仅在61%的案例中被追踪到。在这些培养基中，首次检测到沙门氏菌的时间也略有增加（表1）。沙门氏菌可被追踪到的时间段在蛋白胨肉汤中同样最高，相对于整个测试期为57%（四硫磺酸盐肉汤：55%，水：51%，亚硒酸盐肉汤：39%（表1）。由此可以得出结论，蛋白胨肉汤是最佳的预增菌培养基，在其中接种的沙门氏菌在大约24小时后可能变得可被追踪到。四硫磺酸盐肉汤的不利程度也不是很高，到目前为止它一直被视为唯一的选择性培养基。然而，在这种情况下，必须面对这样一种可能性，即预先受损的沙门氏菌直到培养几天后甚至在强酸性pH值下才开始增加。
