Background

Persistent organic pollutants (POPs) such as dioxins, dioxin-like chemicals and non-dioxin-like PCBs causing adverse effects to human health bio-accumulate through the food web due to their affinity for adipose tissues. Foods of animal origin are therefore the main contributors to human dietary exposure. The European Union’s (EU) food safety policy requires checking of a wide range of samples for compliance with legal limits on a regular basis. Several methods of varying efficiency are applied by official control laboratories for extraction of the different classes of lipids and associated POPs, bound to animal tissue and animal products in varying degrees, sometimes leading to discrepancies especially in fresh weight based analytical results.

Results

Starting from Smedes’ lipid extraction from marine tissue, we optimized the extraction efficiency for both lipids and lipophilic pollutants, abandoning the time-consuming centrifugation step. The resulting modified Smedes extraction (MSE) method was validated based on multiple analyses of a large number of real-world samples, matrix calibration and performance assessment in proficiency testing utilizing both instrumental and bioanalytical methodologies. Intermediate precision in 12 different foods was below 3% in chicken eggs, egg powder, animal fat, fish, fish oil, poultry, whole milk, milk fat and milk powder, and below 5% in bovine meat, liver, and infant food. In comparison to Twisselmann hot extraction, results presented here show an increased efficiency of MSE by + 25% for bovine liver, + 14% for chicken eggs, + 13% for poultry meat, + 12% for fish, 8% for bovine meat, and 6% for infant food.

Conclusions

For the first time, a fast and reliable routine method is available that enables the analyst to reproducibly extract "total" lipids from any EU-regulated food sample of animal origin within 6 to 8 min. Increased efficiency translates into a considerable increase in both lipid and wet weight-based analytical results measured for associated POPs, reducing the risk of false non-compliant results. Compared to a 4 h Twisselmann extraction, the extraction of 1000 samples using MSE would result in annual savings of about 250 h or 32 working days. Our MSE procedure contributes to the European Commission's objective of harmonizing analytical results across the EU generated according to Commission Regulation (EU) 2017/644.

中文翻译：

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从所有欧盟监管的动物源食品中快速提取总脂质和亲脂性持久性有机污染物：Smedes 方法的重新审视和改进

 背景

二恶英、二恶英类化学物质和非二恶英类多氯联苯等持久性有机污染物（POP）对人类健康造成不利影响，由于它们对脂肪组织的亲和力，会通过食物网进行生物累积。因此，动物源性食品是人类饮食暴露的主要来源。欧盟 (EU) 食品安全政策要求定期检查各种样品是否符合法律限制。官方控制实验室采用几种不同效率的方法来提取不同类别的脂质和相关持久性有机污染物，这些脂质和相关持久性有机污染物在不同程度上与动物组织和动物产品结合，有时会导致差异，特别是基于鲜重的分析结果。

 结果

从Smedes从海洋组织中提取脂质开始，我们优化了脂质和亲脂性污染物的提取效率，放弃了耗时的离心步骤。基于对大量真实样品的多次分析、基质校准和利用仪器和生物分析方法进行能力验证的性能评估，对所得改进的Smedes提取 (MSE) 方法进行了验证。鸡蛋、蛋粉、动物脂肪、鱼、鱼油、家禽、全脂奶、乳脂和奶粉等12种食品的中间精密度均低于3%，牛肉、肝脏、婴儿食品的中间精密度均低于5%。与Twisselmann热提取相比，此处提供的结果显示，MSE 效率提高了：牛肝 + 25%、鸡蛋 + 14%、家禽肉 + 13%、鱼 + 12%、牛肉 + 8%、婴儿食品占 6%。

 结论

首次提供了一种快速可靠的常规方法，使分析人员能够在 6 至 8 分钟内从任何欧盟监管的动物源食品样品中重复提取“总”脂质。效率的提高意味着相关 POP 的基于脂质和湿重的分析结果显着增加，从而降低了错误的不合规结果的风险。与 4 小时Twisselmann提取相比，使用 MSE 提取 1000 个样品每年可节省约 250 小时或 32 个工作日。我们的 MSE 程序有助于实现欧盟委员会根据委员会法规 (EU) 2017/644 协调整个欧盟分析结果的目标。