Development of a Fluorescence Polarization Assay for the Determination of Aflatoxins in Grains

Abstract

Aflatoxins produced by Aspergillus flavus are commonly found in human and animal foods including grains, cereals, peanut products, sorghum, and soy seeds. Exposure to aflatoxins has been associated with carcinogenicity. This paper reports a simple, portable, and rapid fluorescence polarization (FP) assay for aflatoxin determination in grains. This immunoassay is field portable, homogeneous, and without any washing and cleaning steps. The assay is based upon the competition between free aflatoxin and an aflatoxin-fluorescein tracer for an aflatoxin-specific monoclonal antibody in solution. A series of naturally contaminated corn, sorghum, peanut butter, and peanut paste samples were analyzed by FP and compared with HPLC results. Similarly, spiked popcorn samples were analyzed by FP. FP results of naturally contaminated samples correlated well with HPLC (r (2) = 0.97). FP analysis of spiked popcorn samples (with a mixture of B(1)/B(2)/G(1)/G(2), 7/1/3/1, w/w) gave a good correlation with spiked values (r (2) = 0.99). However, FP consistently underestimated the aflatoxin contents. This was perhaps due to low cross-reactivity of the antibody used toward B(2), G(1), and G(2) aflatoxins. These results combined with the portability and simplicity of the assay suggest that the assay can be used for screening total aflatoxin in grains.

Aflatoxin levels and exposure assessment of Spanish infant cereals

“…Aflatoxins are frequently found in many foodstuffs for humans or animals (Ali et al 2005, Nasir and Jolley 2002, Park 2002, Chiavaro et al 2001 and from all food-contaminating aflatoxins, AFB 1 is usually the predominant mycotoxin (Jolly et al 2006). Commonly, aflatoxins contaminate those foodstuffs with a high proportion of carbohydrates and lipids (Nilufer and Boyacioglu 2002) such as nuts (peanuts, pistachios, walnuts), dried fruits (figs), corn (maize), spices (pepper), seeds, milk, cocoa, beer (Cavaliere et al 2007, Bourais et al 2006, Nilufer and Boyacioglu 2002, Stroka et al 2000.…”

Aflatoxins: Their Measure and Analysis

“…In particular, it does not require additional manipulations, such as the washing steps of competitive ELISAs, making it simple, rapid, also field portable and, therefore, useful for screening purpose. A homogeneous assay for determining the aflatoxin content in agricultural products based on the technique of fluorescence polarization has been described (Nasir & Jolley, 2002). The disadvantage of this technique is that the aflatoxin contents are underestimated, probably because of the low cross-reactivity of the antibody with AFB2, AFG1 and AFG2.…”

Myco-toxins Monitoring Device and their Management Strategies through Detoxifying Agents in Feed

“…Based on the Lambert-Beer's law stated that "absorbance is proportional to the concentrations of the attenuating species in the material sample" in 1852 (Valeur, 2001 (Nasir and Jolley, 2002). There are three type of FP-based biosensor based on their structureFluorescence resonance energy transfer (FRET)-based biosensor: FRET describe the energy transfer between two chromophores.…”