Search

Abstract: Egg allergy is an important public health and safety concern, so quantification and administration of food or vaccines containing ovalbumin (OVA) are urgently needed. This study aimed to establish a rapid and sensitive magnetic particles–chemiluminescence enzyme immunoassay (MPs–CLEIA) for the determination of OVA. The proposed method was developed on the basis of a double antibodies sandwich immunoreaction and luminol–H2O2 chemiluminescence system. The MPs served as both the solid phase and separator, the anti-OVA MPs-coated polyclonal antibodies (pAbs) were used as capturing antibody, and the horseradish peroxidase (HRP)-labeled monoclonal antibody (mAb) was taken as detecting antibody. The parameters of the method were evaluated and optimized. The established MPs–CLEIA method had a linear range from 0.31 to 100ng/ml with a detection limit of 0.24ng/ml. The assays showed low reactivities and less than 5% of intraassay and interassay coefficients of variation (CVs), and the average recoveries were between 92 and 97%. Furthermore, the developed method was applied in real samples analysis successfully, and the correlation coefficient with the commercially available OVA kit was 0.9976. Moreover, it was more rapid and sensitive compared with the other methods for testing OVA. [Copyright &y& Elsevier]

Abstract: A lateral flow immunochromatographic (LFIC) test strip based on a colloidal gold–monoclonal antibody (McAb) conjugate was developed for on-site rapid detection of okadaic acid (OA) in shellfish. It applies a competitive format using an immobilized toxin conjugate and free toxin present in samples. The McAb against OA was conjugated with 20-nm colloidal gold as detector reagent. The toxin in the sample competed with the immobilized toxin to bind to the gold conjugated with McAb. The colloidal gold/McAb/toxin mobile complex was not captured by OA–bovine serum albumin (BSA) on the test line, but it was captured by goat anti-mouse immunoglobulin G (IgG) on the control line. The color density of the test line correlated with the concentration of toxin in the range of 10–50ngml−1. The qualitative detection limit of 150μgkg−1 sample was close to the European Union (EU) regulatory limit (160μgkg−1). Therefore, these strips were able to directly and qualitatively estimate the consuming safety of shellfish. They require no equipment because of available visual results, and they screened numerous samples within 10min. The results were further confirmed by high-performance liquid chromatography tandem mass spectrometry (HPLC–MS/MS). As a food safety screening tool, the test strips are convenient and useful to rapidly on-site test the presence of OA in shellfish products. [Copyright &y& Elsevier]