Food Allergy Research and Resource Program at the University of Nebraska-Lincoln, 143 Food Industry Complex, Lincoln, NE 68583-0919, USA.
J Agric Food Chem. 2010 Sep 22;58(18):10085-91. doi: 10.1021/jf101718f.
Food products and ingredients are frequently tested for the presence of undeclared allergenic food residues (including milk) using commercial enzyme-linked immunosorbent assays (ELISAs). However, little is understood about the efficacy of these kits with thermally processed foods. This study evaluated the performance of three milk ELISA kits with a model food processed by several methods. A model food (pastry dough squares) was spiked with nonfat dry milk at several concentrations. The pastry squares were processed by boiling (100 °C for 2 min), baking (190 °C for 30 min), frying (190 °C for 2 min), and retorting (121 °C for 20 min with 17 psi overpressure). Samples were analyzed with three commercial ELISA kits: Neogen Veratox Total Milk, ELISA Systems β-lactoglobulin, and ELISA Systems casein. The detection of milk residues depended upon the type of processing applied to the food and the specific milk analyte targeted by the ELISA kit. Poor recoveries were obtained in all processed samples (2-10% of expected values) using the β-lactoglobulin kit. Better recoveries were obtained in boiled samples (44 and 59%, respectively) using the total milk and casein kits. However, these kits performed poorly with baked (9 and 21%) and fried (7 and 18%) samples. Moderate recoveries were observed in retorted samples (23 and 28%). The decreased detection in processed samples is likely due to protein modifications, including aggregation and Maillard reactions, which affect the solubility and immunoreactivity of the antigens detected by the ELISA methods. The observed decreases in ELISA detection of milk are dramatic enough to affect risk-assessment decisions. However, a lower detection of milk residues does not necessarily indicate decreased allergenicity. These ELISA kits are not acceptable for all applications, and users should understand the strengths and limitations of each method.
食品和食品成分经常使用商业酶联免疫吸附测定法（ELISA）检测未申报的过敏原残留（包括牛奶）。然而，对于热处理食品，这些试剂盒的效果知之甚少。本研究评估了三种牛奶 ELISA 试剂盒在几种方法处理的模型食品中的性能。用几种浓度的脱脂奶粉对模型食品（糕点面团方块）进行了掺杂。将糕点方块通过煮沸（100°C 2 分钟）、烘烤（190°C 30 分钟）、油炸（190°C 2 分钟）和高压蒸煮（121°C 20 分钟，超压 17psi）进行处理。使用三种商业 ELISA 试剂盒：Neogen Veratox 总牛奶、ELISA Systems β-乳球蛋白和 ELISA Systems 酪蛋白对样品进行分析。牛奶残留的检测取决于应用于食品的加工类型和 ELISA 试剂盒针对的特定牛奶分析物。使用 β-乳球蛋白试剂盒在所有加工样品中（分别为预期值的 2-10%）均获得较差的回收率。使用总牛奶和酪蛋白试剂盒在煮沸样品中获得了更好的回收率（分别为 44%和 59%）。然而，这些试剂盒在烘烤（9%和 21%）和油炸（7%和 18%）样品中的性能较差。在高压蒸煮样品中观察到中等回收率（23%和 28%）。在加工样品中检测到的减少可能是由于蛋白质修饰，包括聚集和美拉德反应，这会影响 ELISA 方法检测到的抗原的溶解度和免疫反应性。ELISA 检测牛奶的减少足以影响风险评估决策。然而，牛奶残留量的减少并不一定表示致敏性降低。这些 ELISA 试剂盒并非所有应用都适用，用户应了解每种方法的优缺点。
