Hefle S L, Jeanniton E, Taylor S L
University of Nebraska-Lincoln, Department of Food Science and Technology, 68583-0919, USA.
J Food Prot. 2001 Nov;64(11):1812-6. doi: 10.4315/0362-028x-64.11.1812.
Chicken eggs are used extensively as an excellent source of dietary proteins. These proteins have many functional properties, making them valuable food ingredients. However, eggs are a frequent cause of food hypersensitivity, especially in children. Of major concern to food processors is the inadvertent cross-contact of food products with allergenic residues, which could result in potentially life-threatening reactions in those with a food allergy. The aim of the present study was to develop an enzyme-linked immunosorbent assay (ELISA) for the detection of undeclared egg residues in foods. Commercially purified ovalbumin (OVA) and dehydrated egg white solids were used as antigens to induce antibodies in rabbits and goats. Reference pasta standards and various food samples were extracted, then clarified by centrifugation. Goat anti-egg white antibodies were used as the capture reagent, nonspecific sites were blocked with gelatin, then standard and sample extracts were added. Rabbit anti-OVA antibodies were used as detector antibodies, followed by addition of commercial goat anti-rabbit IgG antibody labeled with alkaline phosphatase and subsequent substrate addition. Twenty brands of egg-free pasta (two lots each) were analyzed using the ELISA. Fourteen common pasta ingredients were also evaluated for cross-reactivity problems in the method. The detection limit of the assay was 1 ppm spray-dried whole egg. Fifty-five percent (22 samples) of the egg-free pasta samples tested positive for the presence of undeclared egg residues, with values ranging from 1 to >100,000 ppm. Minimal cross-reactivity was encountered in general, but portobello mushrooms and basil caused some minor matrix effects. This sandwich-type ELISA method can be used to detect undeclared egg residues in processed foods and to evaluate industrial clean-up operations.
鸡蛋被广泛用作膳食蛋白质的优质来源。这些蛋白质具有多种功能特性，使其成为有价值的食品成分。然而，鸡蛋是食物过敏的常见诱因，尤其是在儿童中。食品加工商主要关注的是食品产品与过敏原残留的意外交叉接触，这可能会导致食物过敏者产生潜在的危及生命的反应。本研究的目的是开发一种酶联免疫吸附测定（ELISA）方法，用于检测食品中未申报的鸡蛋残留。使用商业纯化的卵清蛋白（OVA）和脱水蛋清固体作为抗原，在兔子和山羊体内诱导产生抗体。提取参考面食标准品和各种食品样品，然后通过离心进行澄清。使用山羊抗蛋清抗体作为捕获试剂，用明胶封闭非特异性位点，然后加入标准品和样品提取物。使用兔抗OVA抗体作为检测抗体，随后加入用碱性磷酸酶标记的商业山羊抗兔IgG抗体，再加入底物。使用ELISA分析了20个品牌的无蛋面食（每个品牌两批）。还评估了14种常见面食成分在该方法中的交叉反应问题。该测定方法的检测限为1 ppm喷雾干燥全蛋。在检测的无蛋面食样品中，55%（22个样品）检测出存在未申报的鸡蛋残留，含量范围为1至>100,000 ppm。总体而言，交叉反应极小，但褐蘑菇和罗勒引起了一些轻微的基质效应。这种夹心型ELISA方法可用于检测加工食品中未申报的鸡蛋残留，并评估工业清洁操作。
