Qualitative Method for Determination of Aflatoxin B1 in Nuts

Abstract

The proper characterization of a commercial qualitative method for determining aflatoxin B1 in some nuts is described. A qualitative method that provides binary responses of the yes/no type means that the performance parameters have been properly adapted and defined. Performance characteristics such as the cut-off limit, the detection limit, sensitivity, specificity, false-positive and negative rates, and the unreliability or uncertainty region are defined and then estimated by means of the performance characteristic curves. The commercial test kit showed the cut-off limit at 1.6 ng/g, with a sensitivity rate of 95% and a false-negative rate of zero. A modification can be performed to shift the cut-off to 2.0 ng/g, keeping the same values for the sensitivity and false-negative rate.

Occurrence, Toxicity, and Analysis of Major Mycotoxins in Food

“…Flow-through membranes utilize the same basic principle as LFD but may not yield accurate results near the detection limit [ 107 , 109 ]. Flow-through immunoassays have been developed for screening OTA in green and roasted coffee [ 114 , 115 ], AFB1 in nuts [ 116 ], and ZEA in cereals and feed samples [ 117 ]. Although many different rapid strip tests have been developed for detection of major mycotoxins in different food commodities, they are not commonly used in the field and not commercially successful due to problems related to sensitivity, cost, and accuracy [ 109 ].…”

Application and validation of a clean-up tandem assay column for screening ochratoxin A in cocoa powder

“…An intra-laboratory validation was performed with blank cocoa powder samples fortified at 0, 1, 2, 3, 4 and 5 µg OTA kg -1 the night before using the afore mentioned working solutions in MeOH. The following performance characteristics were determined: 275 precision (in terms of false positive and false negative results), sensitivity, specificity, positive and negative predictive values and unreliability region (Trullols et al 2004a, Trullols et al 2004b.…”

“…In case of a suspected non-compliant result, this result shall be confirmed by a confirmatory method. Tables II and III Performance characteristics were also estimated by a curve (Trullols et al 2004b). Blank cocoa powder samples were fortified at 0, 0.5, 1, 1.5, 2, 3, 4 and 5 µg OTA kg -1 the night before using the afore mentioned working solutions in MeOH.…”