A comparison of time-resolved fluoroimmunoassay and ELISA in the detection of casein in foodstuffs

Abstract

With the aim of lowering the detection limit for casein in foods, three competitive assays are described: direct time-resolved fluoroimmunoassay (TR-FIA), using europium-conjugated antibody, indirect TR-FIA, using biotinylated antibody with europium-conjugated streptavidin and ELISA, using a HRP-conjugated secondary antibody. Food samples (instant potato, flour mix, packet soup, spice-mix) were analysed. Standard curve sensitivities in direct and indirect TR-FIAs did not differ significantly (p0/0.097), but both TR-FIAs were considerably less sensitive (both p B/0.0001) than ELISA (LOQs 1.3, 1.5 and B/1.0 mg kg (1 , respectively). The precision and working analyte range was similar in all three methods. Casein content measured in food products was comparable, using the three assays and rocket immunoelectrophoresis. The TR-FIA approach provided no improvement over the ELISA. All three assays allowed quantification of casein in foodstuffs in the order of 1 Á/1.5 mg kg (1 , providing a basis for more rigorous validation and collaborative testing.

Development of a Monoclonal Antibody-Based Sandwich ELISA for Peanut Allergen Ara h 1 in Food

“…The most commonly used analytical method for allergen detection is based on the enzyme-linked immunosorbent assay (ELISA) technique owing to its high sensitivity and specificity without the need for sophisticated equipment [13,14,15]. Here, we report the development of a mAb-based sandwich ELISA to monitor content of the peanut allergen Ara h 1 in foods by comparing sequential Ara h 1 levels.…”

Fluorescent microspheres lateral flow assay for sensitive detection of the milk allergen casein

“…To prevent allergy-inducing ingredients from contaminating food products, researchers should develop a rapid method for detecting casein in food products. The methods currently used to detect the presence of milk allergens in food products mainly include enzyme linked immunosorbent assay (ELISA) (Deng et al, 2012;Peng et al, 2014a;Xuli et al, 2013), immunofluorescence (Young & Nelstrop, 1970), rocket immune-electrophoresis (Moen et al, 2005), time-resolved fluoroimmunoassay (Sletten, Løvberg, Moen, Skarpeid, & Egaas, 2005), immunosensor (Cao et al, 2011;Hiep et al, 2007), high-performance liquid chromatography (Montalbano, Segreto, Di Gerlando, Mastrangelo, & Sardina, 2016;Scano, Murgia, Pirisi, & Caboni, 2014), liquid chromatography/tandem mass spectrometry (Altendorfer et al, 2015;Heick, Fischer, & Pöpping, 2011), and polymerase chain reaction (Schulmeister et al, 2009). However, these methods require expensive equipment, professional operators, and long processing time.…”

Chip-Scale Bioassays Based on Surface-Enhanced Raman Scattering: Fundamentals and Applications

“…74 " 84 ELISA utilizes enzymes as a signal amplifying method. Typical assay procedures involve capture of target analytes into culture wells followed by incubation with antibody.…”