Detection And Evaluation Of F-2 Toxin In Food Packaging Logistics

Zearalenone toxins(F-2 toxins)are widely present in food packaging and seriously threaten people’s health.How to detect F-2 toxins quickly and with high sensitivity is not only the focus of monitoring food and packaging safety,but also the focus of the country and people.An enzyme-free fluorometric assay is described for the detection of F-2 toxins.The method combines(a)catalyzed hairpin assembly(CHA),(b)ultrahigh fluorescent light-up G-rich DNA sequences in proximity to silver nanoclusters(Ag NCs),and(c)the use of aptamers(Apt).In the presence of F-2 toxins,the inhibit sequence(Inh)is released from the aptamer-trigger sequence(Apt-T)via the binding of F-2 toxins and the aptamer of Apt-T.The free Apt-T acts as a switch that opens the hairpins H1 and H2 to generate H1-H2 complex.The released Apt-T is available to trigger the next round of CHA between H1 and H2.Finally,the hybridization between H1 and the Ag NCs probe(P)causes the G-rich sequence to be in close proximity to the dark Ag NCs encapsulated by P.This leads to highly efficient lighting up of the Ag NCs and the production of amplified fluorescence with excitation/emission peaks at 575/628 nm.Under the optimized conditions,a linear correlation was observed with concentrations ranging from 1.3 pg/mL to 100 ng/mL,and the limit of detection was 0.32 pg/mL(S/N=3).The selectivity of the current method was examined by incubating this nanoprobe with different toxin interferents.Finally,the method was successfully validated by analyzing real food in the package for levels of F-2 toxins after a simple sample preparation procedure.The spiked recovery rate of corn was 96.25%～104.15%,and the spiked recovery rate of beer was 101.3%～107.50%,which proved to be successfully used for the real sample detection.In addition,for the methodological comparison,F-2 toxins was also detected by a traditional competitive enzyme-linked immunosorbent assay(ELISA).The detection limit was 0.04 ng/mL and the detection range was 0.05-4.5 ng/mL.The aptamer-based fluorometric zearalenone assay has both an extremely wide detection range and an ultralow limit of detection,which is 3 orders of magnitude higher than the sensitivity of the ELISA.Compared with other excellent detection methods at home and abroad,it also has significant advantages,lower detection limit and wider detection range.