Laboratory of Food Microbiology and Food Preservation, Department of Food Safety and Food Quality, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium.
Laboratory of Food Microbiology and Food Preservation, Department of Food Safety and Food Quality, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium.
Int J Food Microbiol. 2015 Sep 2;208:11-8. doi: 10.1016/j.ijfoodmicro.2015.05.009. Epub 2015 May 21.
Enteric pathogens, such as Salmonella spp. and pathogenic Escherichia coli, have been detected and associated with food borne outbreaks from (imported) fresh leafy herbs. Screening on imported herbs from South East Asian countries has been described. However, limited information on prevalence of these pathogens is available from other sourcing regions. Therefore, fresh pre-packed basil and coriander leaves from a Belgian trading company were investigated for the presence of Salmonella spp., Shiga toxin-producing E. coli (STEC), generic E. coli and coliforms. In total 592 samples were collected originating from Belgium, Israel and Cyprus during 2013-2014. Multiplex PCR followed by further culture confirmation was used for the detection of Salmonella spp. and STEC, whereas the Petrifilm Select E. coli and VRBL-agar were used, respectively, for the enumeration of E. coli and coliforms. Salmonella was detected in 10 out of 592 samples (25g) (1.7%; 5 from basil and 5 from coriander), of which two samples were sourced from Israel and eight from Cyprus. The presence of STEC was suspected in 11 out of 592 samples (25g) (1.9%; 3 basil and 8 coriander), due to the detection of stx and eae genes, of which one sample originated from Belgium, four from Israel and six from Cyprus. No STEC was isolated by culture techniques, but in three samples a serotype (O26, O103 or O111) with its most likely associated eae-variant (β or θ) was detected by PCR. Generic E. coli was enumerated in 108 out of 592 samples, whereby 55, 32 and 13 samples respectively between 10-100, 100-1000 and 1000-10,000cfu/g and 8 samples exceeding 10,000cfu/g. Coliforms were enumerated in all herb samples at variable levels ranging from 1.6 to 7.5logcfu/g. Further statistics indicate that the E. coli class (categorized by level) was significantly correlated with the presence of Salmonella (p<0.001) or STEC (p=0.019), while coliform counts were significant correlated with Salmonella (p<0.001), but not with STEC (p=0.405). Generic E. coli class is a better indicator for the presence of enteric pathogens than coliforms on fresh herbs, but the relationship between E. coli and Salmonella or STEC was not strong enough to provide a threshold value for E. coli to assure food safety (i.e. no pathogens present). Results indicate that fresh leafy herbs like basil and coriander sourced from different cultivation regions, may contain enteric pathogens and potentially pose a risk for human health.
肠病原体，如沙门氏菌和致病性大肠杆菌，已被检测到并与食源性疾病暴发有关（进口）新鲜叶类草药。已经描述了对来自东南亚国家的进口草药的筛选。然而，来自其他来源地区的这些病原体的流行情况的信息有限。因此，对来自比利时贸易公司的新鲜预包装罗勒和香菜叶进行了沙门氏菌、产志贺毒素大肠杆菌（STEC）、普通大肠杆菌和大肠菌群的检测。在 2013-2014 年期间，共采集了来自比利时、以色列和塞浦路斯的 592 个样本。采用多重 PCR 结合进一步的培养确认法检测沙门氏菌和 STEC，而采用 Petrifilm Select 大肠杆菌和 VRBL-琼脂分别对大肠杆菌和大肠菌群进行计数。在 592 个样本（25g）（1.7%；5 个来自罗勒，5 个来自香菜）中检测到沙门氏菌，其中 2 个样本来自以色列，8 个来自塞浦路斯。由于stx 和 eae 基因的检测，怀疑 592 个样本（25g）中有 11 个样本（1.9%；3 个罗勒和 8 个香菜）含有 STEC，其中一个样本来自比利时，4 个来自以色列，6 个来自塞浦路斯。通过培养技术未分离出 STEC，但在 3 个样本中通过 PCR 检测到血清型（O26、O103 或 O111）及其最可能相关的 eae 变体（β 或θ）。在 592 个样本中计数了普通大肠杆菌，其中 55、32 和 13 个样本分别在 10-100、100-1000 和 1000-10000cfu/g 之间，8 个样本超过 10000cfu/g。在所有草药样本中均以 1.6 至 7.5logcfu/g 的可变水平计数大肠菌群。进一步的统计数据表明，大肠杆菌类（按水平分类）与沙门氏菌（p<0.001）或 STEC（p=0.019）的存在显著相关，而大肠菌群计数与沙门氏菌显著相关（p<0.001），但与 STEC 不相关（p=0.405）。普通大肠杆菌类是新鲜草药中肠病原体存在的更好指标，而大肠杆菌与沙门氏菌或 STEC 之间的关系不够强，无法提供大肠杆菌的阈值以确保食品安全（即无病原体存在）。结果表明，来自不同种植地区的新鲜叶类草药，如罗勒和香菜，可能含有肠病原体，并可能对人类健康构成威胁。
