Penicillium camemberti and Penicillium roqueforti Enhance the Growth and Survival of Shiga Toxin-Producing Escherichia coli O157 under Mild Acidic Conditions
Penicillium camemberti and Penicillium roqueforti Enhance the Growth and Survival of Shiga Toxin-Producing Escherichia coli O157 under Mild Acidic Conditions
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DOI：
10.1111/j.1750-3841.2011.02533.x
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发表时间：
2012-02-01
影响因子：
3.9
通讯作者：
Kumagai, Susumu
中科院分区：
文献类型：
--
作者：
Lee, Ken-ichi;Watanabe, Maiko;Kumagai, Susumu
在3个模型系统中，研究了普通霉菌成熟干酪的二次发酵剂霉菌对产志贺滋贺毒素大肠杆菌（STEC）O 157的影响。在第一个模型中，将8个STEC O 157菌株在25 ℃的弱酸性条件下在卡门伯青霉或罗克弗青霉的废培养物中孵育。在pH4.8 ~ 5.0的霉菌培养液中，STEC O 157生长的滞后时间明显短于在新鲜培养基中观察到的滞后时间。对卡门贝氏假单胞菌培养物的分析表明，生长增强的病原体是由霉菌响应于酸性环境而产生的，并且在热处理中没有完全灭活。在第二个模型中，在25 ℃的酸化牛奶中共培养卡门贝氏毕赤酵母和STEC O 157。STEC O 157的种群在霉菌存在下达到108 CFU/mL，而在霉菌不存在下种群稳定下降。虽然这种生长增强部分归因于霉菌的碱化，但即使在该模型的pH稳定时也观察到。在第三个模型中，将2个STEC O 157菌株在pH 4.5和10 ℃下在霉菌的废培养物中孵育。除1株STEC O 157菌株外，其他菌株的损伤细胞比例均显著低于对照组，D值显著高于对照组。这些结果表明，霉菌可以通过改变环境来促进STEC O 157的生长和存活。
The effects of secondary starter molds of common mold-ripened cheeses on the Shiga toxin-producing Escherichia coli (STEC) O157 were assessed in 3 model systems. In the 1st model, 8 STEC O157 strains were incubated in the spent culture of Penicillium camemberti or Penicillium roqueforti under mild acidic conditions at 25 degrees C. In the spent cultures of the mold at pH 4.8 to 5.0, the lag times of STEC O157 growth were significantly shorter than those observed in fresh medium. Analyses of the spent culture of P. camemberti showed that the causative agents of the growth enhancement were produced by the mold in response to an acidic environment and were not fully inactivated in heat treatment. In the 2nd model, P. camemberti and STEC O157 were cocultured in acidified milk at 25 degrees C. The population of STEC O157 reached 108 CFU/mL in the presence of the mold, whereas the population steadily declined in the absence of the mold. Although this growth enhancement was partially attributable to alkalization by the mold, it was observed even when the pH of this model was stabilized. In the 3rd model, 2 STEC O157 strains were incubated in the spent cultures of molds at pH 4.5 at 10 degrees C. In the spent culture, proportions of injured cells were significantly lower and D values were significantly higher than those in control, except one STEC O157 strain in the spent culture of P. camemberti. These results showed that the molds could enhance the growth and survival of STEC O157 by changing the environment.