Ohkochi Miho, Nakazawa Miyuki, Sashihara Nobuhiro
Research and Development Division, Q.P. Corporation, 5-13-1, Sumiyoshi-cho, Fuchu-shi, Tokyo, 183-0034, Japan.
J Food Prot. 2009 Jan;72(1):178-81. doi: 10.4315/0362-028x-72.1.178.
Unpasteurized liquid whole-egg samples were collected from six and seven commercial establishments across Japan in 1993 and 1994 and in 2005, respectively. The samples were tested for the presence of Listeria spp. and Listeria monocytogenes. Detection rates of the Listeria spp. were greatly different among the egg-breaking facilities, with a range of 8 to 55%. There was no significant difference in the contamination rate between the samples from 1993 and 1994 and from 2005. L. monocytogenes was isolated from 2 of 487 (0.4%) samples in 1993 and 1994, and 2 of 316 (0.6%) samples in 2005. These detection rates are lower than known detection rates of other livestock products (5.1 to 42%). In 2005, the L. monocytogenes-positive samples were quantified by a most-probable-number counting experiment, and the contamination levels were below 7.5 organisms per 25 g of sample. D55 degrees C-values of 0.59 to 4.08/min were determined for L. monocytogenes isolated in this study. This heat tolerance is in a good agreement with past reports, and slightly higher than that of Salmonella. This study suggests that the legal pasteurization condition of liquid egg is sufficient to ensure microbial safety against L. monocytogenes because the contamination rate and its level are considerably low.
1993年和1994年以及2005年，分别从日本各地的6家和7家商业机构采集了未经巴氏杀菌的液态全蛋样本。对样本进行了李斯特菌属和单核细胞增生李斯特菌检测。在打蛋场所中，李斯特菌属的检出率差异很大，范围为8%至55%。1993年和1994年的样本与2005年的样本在污染率上没有显著差异。1993年和1994年，在487份样本中有2份（0.4%）分离出单核细胞增生李斯特菌，2005年在316份样本中有2份（0.6%）分离出该菌。这些检出率低于其他畜产品已知的检出率（5.1%至42%）。2005年，通过最大可能数计数实验对单核细胞增生李斯特菌阳性样本进行了定量，污染水平低于每25克样本7.5个菌。本研究中分离出的单核细胞增生李斯特菌的D55℃值为0.59至4.08/分钟。这种耐热性与过去的报告一致，略高于沙门氏菌。本研究表明，液态蛋的法定巴氏杀菌条件足以确保针对单核细胞增生李斯特菌的微生物安全性，因为污染率及其水平相当低。
