Enterotoxigenic Escherichia coli (ETEC) causes acute diarrhea and is transmitted through contaminated food and water; however, systematic procedures for its specific detection in foods have not been established. To establish an efficient detection method for ETEC in food, an interlaboratory study using ETEC O148 and O159 as representative serogroups was first conducted with 13 participating laboratories. A series of tests including enrichment, real-time PCR assays, plating on selective agars, and concentration by immunomagnetic separation followed by plating onto selective agar (IMS-plating methods) were employed. This study particularly focused on the detection efficiencies of real-time PCR assays for enterotoxin genes (sth, stp, and lt), IMS-plating methods, and direct plating onto sorbitol MacConkey agar and CHROMagar STEC medium, supplemented with tobramycin, which is a novel modification in the preparation of a selective agar. Cucumber and leek samples inoculated with ETEC O148 and O159, either at 4–7 CFU/25 g (low levels) or at 21–37 CFU/25 g (high levels) were used as samples with uninoculated samples used as controls. At high inoculation levels, the sensitivities of sth, stp, and lt detection, direct-plating, and IMS-plating methods in cucumber inoculated with O148 and in both foods inoculated with O159 were 100%. In leek inoculated with high levels of O148, the sensitivities of sth, stp, and lt detection, direct-plating, and the IMS-plating method were 76.9%, 64.1%, and 74.4%, respectively. At low inoculation levels, the sensitivities of sth, stp, and lt detection, direct plating, and IMS-plating method in cucumber inoculated with O148 and in both foods inoculated with O159 were in the range of 87.2–97.4%. In leek inoculated with low levels of O148, the sensitivities of sth, stp, and lt detection, direct plating, and the IMS-plating method were 59.0%, 33.3%, and 38.5%, respectively. Thus, ETEC in food contaminated with more than 21 CFU/25 g were detected at high rate (over 74%) using real-time PCR assays and IMS-plating onto selective agar. Therefore, screening sth, stp, and lt genes followed by isolation of STEC using the IMS-plating method may be an efficient method for ETEC detection.

肠毒素性大肠杆菌（ETEC）引起急性腹泻，并通过受污染的食物和水传播；但是，尚未建立在食品中进行特定检测的系统程序。为了建立食品中ETEC的有效检测方法，首先与13个参与实验室进行了以ETEC O148和O159为代表血清群的实验室间研究。使用了一系列测试，包括富集，实时PCR分析，在选择性琼脂上进行平板接种，通过免疫磁分离进行浓缩，然后在选择性琼脂上进行平板电镀（IMS平板电镀方法）。这项研究特别关注肠毒素基因（sth，stp和lt）的实时PCR分析的检测效率），IMS铺板方法，然后直接铺板在山梨糖醇MacConkey琼脂和CHROMagar STEC培养基上，并补充妥布霉素，这是制备选择性琼脂的一种新颖修饰。分别以4-7 CFU / 25 g（低水平）或21-37 CFU / 25 g（高水平）接种ETEC O148和O159的黄瓜和韭菜样品作为样品，而未接种的样品用作对照。在高接种水平下，接种O148的黄瓜和接种O159的两种食品中sth，stp和lt检测，直接接种和IMS接种方法的敏感性均为100％。在高浓度O148接种的韭菜中，sth，stp和lt的敏感性检测率，直接电镀率和IMS电镀率分别为76.9％，64.1％和74.4％。在低接种水平下，接种O148的黄瓜和两种接种O159的食物中sth，stp和lt检测，直接接种和IMS接种方法的敏感性在87.2–97.4％的范围内。在低浓度O148接种的韭菜中，sth，stp和lt检测，直接电镀和IMS电镀方法的灵敏度分别为59.0％，33.3％和38.5％。因此，使用实时PCR分析和IMS平板接种在选择性琼脂上，可以高比率（超过74％）检测到被21 CFU / 25 g以上污染的食品中的ETEC。因此，筛选sth，stp和lt 使用IMS-plating方法分离STEC基因可能是ETEC检测的有效方法。