Nia Yacine, Mutel Isabelle, Assere Adrien, Lombard Bertrand, Auvray Frederic, Hennekinne Jacques-Antoine
Laboratory for food safety, ANSES, Université Paris-Est, F-94700 Maisons-Alfort, France.
Toxins (Basel). 2016 Apr 13;8(4):107. doi: 10.3390/toxins8040107.
Staphylococcal food poisoning outbreaks are a major cause of foodborne illnesses in Europe and their notifications have been mandatory since 2005. Even though the European regulation on microbiological criteria for food defines a criterion on staphylococcal enterotoxin (SE) only in cheese and dairy products, European Food Safety Authority (EFSA) data reported that various types of food matrices are involved in staphylococcal food poisoning outbreaks. The European Screening Method (ESM) of European Union Reference Laboratory for Coagulase Positive Staphylococci (EURL CPS) was validated in 2011 for SE detection in food matrices and is currently the official method used for screening purposes in Europe. In this context, EURLCPS is annually organizing Inter-Laboratory Proficiency Testing Trials (ILPT) to evaluate the competency of the European countries' National Reference Laboratories (NRLs) to analyse SE content in food matrices. A total of 31 NRLs representing 93% of European countries participated in these ILPTs. Eight food matrices were used for ILPT over the period 2013-2015, including cheese, freeze-dried cheese, tuna, mackerel, roasted chicken, ready-to-eat food, milk, and pastry. Food samples were spiked with four SE types (i.e., SEA, SEC, SED, and SEE) at various concentrations. Homogeneity and stability studies showed that ILPT samples were both homogeneous and stable. The analysis of results obtained by participants for a total of 155 blank and 620 contaminated samples allowed for evaluation of trueness (>98%) and specificity (100%) of ESM. Further to the validation study of ESM carried out in 2011, these three ILPTs allowed for the assessment of the proficiency of the NRL network and the performance of ESM on a large variety of food matrices and samples. The ILPT design presented here will be helpful for the organization of ILPT on SE detection by NRLs or other expert laboratories.
葡萄球菌食物中毒暴发是欧洲食源性疾病的主要原因，自2005年起对其通报成为强制性要求。尽管欧洲食品微生物标准法规仅对奶酪和乳制品规定了葡萄球菌肠毒素（SE）的标准，但欧洲食品安全局（EFSA）的数据显示，各类食品基质都与葡萄球菌食物中毒暴发有关。欧盟凝固酶阳性葡萄球菌参考实验室（EURL CPS）的欧洲筛查方法（ESM）于2011年通过验证，用于检测食品基质中的SE，目前是欧洲用于筛查目的的官方方法。在此背景下，EURL CPS每年组织实验室间能力验证试验（ILPT），以评估欧洲各国国家参考实验室（NRL）分析食品基质中SE含量的能力。共有代表93%欧洲国家的31个NRL参与了这些ILPT。在2013 - 2015年期间，8种食品基质被用于ILPT，包括奶酪、冻干奶酪、金枪鱼、鲭鱼、烤鸡、即食食品、牛奶和糕点。食品样本中添加了四种不同浓度的SE类型（即SEA、SEC、SED和SEE）。均匀性和稳定性研究表明，ILPT样本既均匀又稳定。对参与者针对总共155个空白样本和620个受污染样本所获结果的分析，使得能够评估ESM的准确性（>98%）和特异性（100%）。在2011年对ESM进行验证研究之后，这三项ILPT使得能够评估NRL网络的能力以及ESM在多种食品基质和样本上的性能。此处介绍的ILPT设计将有助于NRL或其他专业实验室组织关于SE检测方面的ILPT。
