Williams Kristina M, Westphal Carmen D, Shriver-Lake Lisa C
US Food and Drug Administration, Center for Food Safety and Applied Nutrition, Laurel, MD 20708, USA.
J AOAC Int. 2004 Nov-Dec;87(6):1485-91.
Egg is one of the 5 major allergenic foods that are responsible for more than 3/4 of food allergies in children. Food-allergic responses can be controlled by avoidance of the offending foods. The applicability of a commercial enzyme-linked immunosorbent assay (ELISA) kit for the detection of egg in food products such as cookies, crackers, pretzels, salad dressings, and raw and cooked noodles was evaluated. A preliminary evaluation of an antibody-based biosensor was also performed. A National Institute of Standards and Technology (NIST) whole dried egg powder reference material, SRM 8415, was used as a standard. A homogeneous and stable aqueous egg suspension was prepared for the evaluation of the performance of the Veratox for Egg Allergen Test (Neogen Corp., Lansing, MI). This test does not detect egg yolk proteins. Each gram of the aqueous dried egg suspension contained 643 microg whole dried egg, 0.5 mg thimerosal, and 2.5 mg bovine serum albumin. When cookies, crackers, salad dressings, noodles, and ice cream were spiked at a level of 24 mg/kg SRM 8415, recoveries for whole egg averaged about 28%. All foods containing egg as indicated on the ingredient label were found positive by the Veratox test. No false positives occurred in samples that did not contain eggs. Similar results were obtained using the Naval Research Laboratory (NRL) array biosensor, an evanescent wave fluoroimmunosensor. Results for cooked noodles showed that they contained <1% of the egg found in uncooked noodles. A comparison of extracts from cooked and uncooked noodles by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) revealed differences in protein profiles. The boiling of the noodles could have reduced the immunoreactivity of the egg proteins to the antibodies used in the kit or rendered the egg proteins nonextractable.
鸡蛋是导致儿童超过3/4食物过敏的5种主要致敏食物之一。食物过敏反应可通过避免食用引起过敏的食物来控制。对一种用于检测饼干、薄脆饼干、椒盐脆饼、沙拉酱以及生熟面条等食品中鸡蛋的商用酶联免疫吸附测定（ELISA）试剂盒的适用性进行了评估。还对一种基于抗体的生物传感器进行了初步评估。使用美国国家标准与技术研究院（NIST）的全蛋干粉参考物质SRM 8415作为标准品。制备了均匀稳定的鸡蛋水悬浮液，用于评估鸡蛋过敏原检测试剂盒（Neogen公司，密歇根州兰辛）的性能。该检测方法检测不出蛋黄蛋白。每克鸡蛋水悬浮液含有643微克全蛋干粉、0.5毫克硫柳汞和2.5毫克牛血清白蛋白。当饼干、薄脆饼干、沙拉酱、面条和冰淇淋中添加浓度为24毫克/千克的SRM 8415时，全蛋的回收率平均约为28%。Veratox检测发现，成分标签上标明含有鸡蛋的所有食品均呈阳性。不含鸡蛋的样品未出现假阳性。使用海军研究实验室（NRL）阵列生物传感器（一种倏逝波荧光免疫传感器）也获得了类似结果。熟面条的检测结果表明，其所含鸡蛋量低于生面条中的1%。通过十二烷基硫酸钠聚丙烯酰胺凝胶电泳（SDS-PAGE）对熟面条和生面条提取物进行比较，发现蛋白质谱存在差异。面条煮沸可能降低了鸡蛋蛋白与试剂盒中所用抗体的免疫反应性，或使鸡蛋蛋白无法提取。
