Nakagawa H, Hara-Kudo Y, Kojima T, Ikedo M, Kodaka H, Konuma H, Kumagai S
Tokyo Kenbikvoin Foundation, Higashikurunie, Japan.
Int J Food Microbiol. 2000 Sep 15;60(1):107-10. doi: 10.1016/s0168-1605(00)00325-1.
We tried to detect Escherichia coli O157:H7 in food samples artificially contaminated with freeze-injured E. coli O157:H7 using an enrichment method with modified EC broth supplemented with novobiocin (mEC + n). When the samples were cultured for enrichment immediately after inoculation of freeze-injured cells, E. coli O157:H7 was not detected in 13 out of 18 samples. However, allowing the food samples to stand for 3 h at room temperature prior to enrichment in mEC + n remarkably improved recovery of E. coli O157:H7 except for some acidic foods. E. coli O157:H7 was detected in the acidic foods by introducing a resuscitation step of 3-h of incubation in a non-selective broth at room temperature prior to enrichment with mEC + n.
我们尝试使用添加了新生霉素的改良EC肉汤（mEC + n）富集法，来检测人工污染了冻害大肠杆菌O157:H7的食品样本中的大肠杆菌O157:H7。当在接种冻害细胞后立即进行富集培养时，18个样本中有13个未检测到大肠杆菌O157:H7。然而，在mEC + n中进行富集之前，先让食品样本在室温下放置3小时，除了一些酸性食品外，显著提高了大肠杆菌O157:H7的回收率。对于酸性食品，通过在mEC + n中进行富集之前，先在室温下于非选择性肉汤中培养3小时的复苏步骤，检测到了大肠杆菌O157:H7。
