Food Allergy Research & Resource Program, Dept. of Food Science & Technology, Univ. of Nebraska, Lincoln, NE 68583-0919, USA.
J Food Sci. 2013 Jul;78(7):T1091-3. doi: 10.1111/1750-3841.12146. Epub 2013 May 6.
Initial food industry testing in our laboratory using enzyme-linked immunosorbent assay (ELISA) methods indicated that the darkest caramel color (class IV) unexpectedly contained traces of peanut protein, a potential undeclared allergen issue. Caramel production centers on the heating of sugars, often glucose, under controlled heat and chemical processing conditions with other ingredients including ammonia, sulfite, and/or alkali salts. These ingredients should not contain any traces of peanut residue. We sought to determine the reliability of commercially available peanut allergen ELISA methods for detection of apparent peanut residue in caramel coloring. Caramel color samples of classes I, II, III, and IV were obtained from 2 commercial suppliers and tested using 6 commercially available quantitative and qualitative peanut ELISA kits. Five lots of class IV caramel color were spiked with a known concentration of peanut protein from light roasted peanut flour to assess recovery of peanut residue using a spike and recovery protocol with either 15 ppm or 100 ppm peanut protein on a kit-specific basis. A false positive detection of peanut protein was found in class IV caramel colors with a range of 1.2 to 17.6 parts per million recovered in both spiked and unspiked liquid caramel color samples. ELISA kit spike/recovery results indicate that false negative results might also be obtained if peanut contamination were ever to actually exist in class IV caramel color. Manufacturers of peanut-free products often test all ingredients for peanut allergen residues using commercial ELISA kits. ELISA methods are not reliable for the detection of peanut in class IV caramel ingredients and their use is not recommended with this matrix.
我们实验室最初使用酶联免疫吸附测定（ELISA）方法对食品行业进行检测，结果出人意料地发现，颜色最深的焦糖（IV 类）中含有微量花生蛋白，这可能是未申报的过敏原问题。焦糖的生产过程集中在糖的加热上，通常是葡萄糖，在受控的热量和化学处理条件下，加入其他成分，包括氨、亚硫酸盐和/或碱盐。这些成分不应含有任何花生残留。我们试图确定市售的花生过敏原 ELISA 方法在检测焦糖色素中明显的花生残留时的可靠性。我们从 2 家商业供应商处获得了 I 类、II 类、III 类和 IV 类焦糖色素样本，并使用 6 种市售的定量和定性花生 ELISA 试剂盒进行了测试。将已知浓度的花生蛋白从轻度烘焙花生粉中加入到 5 批 IV 类焦糖色素中，以评估使用基于试剂盒的 15 ppm 或 100 ppm 花生蛋白的加标和回收方案回收花生残留的情况。在未经加标的和加标的液体焦糖色素样本中，均回收了 1.2 至 17.6 百万分之几的花生蛋白，发现 IV 类焦糖色素中存在花生蛋白的假阳性检测。ELISA 试剂盒加标/回收结果表明，如果 IV 类焦糖色素中真的存在花生污染，也可能得到假阴性结果。无花生产品的制造商通常使用商业 ELISA 试剂盒测试所有成分中的花生过敏原残留。ELISA 方法不可靠，不能用于检测 IV 类焦糖成分中的花生，不建议在该基质中使用。
