Ricci Antonia, Allende Ana, Bolton Declan, Chemaly Marianne, Davies Robert, Fernández Escámez Pablo Salvador, Gironés Rosina, Herman Lieve, Koutsoumanis Kostas, Lindqvist Roland, Nørrung Birgit, Robertson Lucy, Ru Giuseppe, Sanaa Moez, Skandamis Panagiotis, Snary Emma, Speybroeck Niko, Kuile Benno Ter, Threlfall John, Wahlström Helene, Adkin Amie, Greiner Matthias, Marchis Daniela, Prado Marta, Da Silva Felicio Teresa, Ortiz-Pelaez Angel, Simmons Marion
EFSA J. 2018 Jul 17;16(7):e05314. doi: 10.2903/j.efsa.2018.5314. eCollection 2018 Jul.
EFSA was requested: to assess the impact of a proposed quantitative real-time polymerase chain reaction (qPCR) 'technical zero' on the limit of detection of official controls for constituents of ruminant origin in feed, to review and update the 2011 QRA, and to estimate the cattle bovine spongiform encephalopathy (BSE) risk posed by the contamination of feed with BSE-infected bovine-derived processed animal protein (PAP), should pig PAP be re-authorised in poultry feed and vice versa, using both light microscopy and ruminant qPCR methods, and action limits of 100, 150, 200, 250 and 300 DNA copies. The current qPCR cannot discriminate between legitimately added bovine material and unauthorised contamination, or determine if any detected ruminant material is associated with BSE infectivity. The sensitivity of the surveillance for the detection of material of ruminant origin in feed is currently limited due to the heterogeneous distribution of the material, practicalities of sampling and test performance. A 'technical zero' will further reduce it. The updated model estimated a total BSE infectivity four times lower than that estimated in 2011, with less than one new case of BSE expected to arise each year. In the hypothetical scenario of a whole carcass of an infected cow entering the feed chain without any removal of specified risk material (SRM) or reduction of BSE infectivity via rendering, up to four new cases of BSE could be expected at the upper 95th percentile. A second model estimated that at least half of the feed containing material of ruminant origin will not be detected or removed from the feed chain, if an interpretation cut-off point of 100 DNA copies or more is applied. If the probability of a contaminated feed sample increased to 5%, with an interpretation cut-off point of 300 DNA copies, there would be a fourfold increase in the proportion of all produced feed that is contaminated but not detected.
欧洲食品安全局（EFSA）被要求：评估拟议的定量实时聚合酶链反应（qPCR）“技术零”对饲料中反刍动物源性成分官方控制检测限的影响；审查并更新2011年的定量风险评估（QRA）；使用光学显微镜和反刍动物qPCR方法，估计在猪用动物蛋白（PAP）重新被批准用于家禽饲料以及反之亦然的情况下，被牛海绵状脑病（BSE）感染的牛源性加工动物蛋白（PAP）污染饲料所带来的牛BSE风险，以及行动限值为100、150、200、250和300个DNA拷贝时的情况。当前的qPCR无法区分合法添加的牛源材料和未经授权的污染，也无法确定任何检测到的反刍动物材料是否与BSE传染性相关。由于材料分布不均、采样实际情况和检测性能等原因，目前饲料中反刍动物源性材料检测监测的灵敏度受到限制。“技术零”将进一步降低其灵敏度。更新后的模型估计，总的BSE传染性比2011年估计的低四倍，预计每年新增BSE病例不到一例。在假设一头感染牛的整个胴体进入饲料链且未去除任何特定风险物质（SRM）或通过炼制降低BSE传染性的情况下，在第95百分位数上限可能预计出现多达四例新的BSE病例。另一个模型估计，如果应用100个或更多DNA拷贝的解释临界点，至少一半含有反刍动物源性材料的饲料将不会被检测到或从饲料链中去除。如果受污染饲料样本的概率增加到5%，解释临界点为300个DNA拷贝，那么所有生产的饲料中受污染但未被检测到的比例将增加四倍。
