Detection Of Ochratoxin A In Food Packaging Logistics

The food safety problem caused by mycotoxins has become the focus of attention in all countries of the world.Ochratoxin is a toxic fungal metabolite produced by certain strains of Penicillium and Aspergillus.Ochratoxin A(OTA)is the most toxic and widely distributed.Food packaging produces OTA during the logistics process.OTA has kidney toxicity,liver toxicity,teratogenicity,carcinogenesis,mutagenicity and immunosuppression effects on animals and humans.Therefore,OTA poses a great threat to animal and human health.In this study,the OTA of contaminated food packaging was used as the detection target,and enzyme-linked immunosorbent(ELISA)and immunobio-barcode combined with CHA amplification technology were used to detect OTA,which realized the highly sensitive detection of OTA in food packaging.The research results of this paper as follows:1.Using the traditional indirect competitive ELISA method,the "S" type curve was fitted under the optimized conditions and the OTA concentration ranged from 0.5ng/mL to 10000 ng/mL.The standard curve was drawn in the range of 500 ng/mL to10000 ng/mL.The linear equation was y=0.3516Logx-0.6822,R2=0.9907,and the detection range IC20-IC80 was calculated to be 166.03 ng/mL-17.80 ?g/mL.The detection limit IC10 was 28.15ng/mL.2.A method for high-sensitivity detection of OTA based on bio-barcode immunoassay and CHA amplification technology was established.AuNPs with a particle size of about 13 nm was prepared by sodium citrate reduction method,and OTA antibody and bio-barcode DNA were modified on AuNPs to form AuNPs probes.Optimized the optimal amount of antibody added.At the same time,the magnetic beads were modified with OTA antigens for rapid separation and enrichment of OTA in the samples.Under the optimal conditions,the OTA concentration ranged from 0.001 ng/mL to 1000 ng/mL.The linear equation was y=-248.0889x+2274.1984,R2=0.9941.The detection limit was calculated to be 0.54pg/mL.The specificity of the detection method was also examined.The results showed that the method has good anti-interference ability to AFB1,T-2 toxin,FBI,ZEN and other mycotoxins.The five kinds of packaged foods of coffee,wine,moldy biscuits,milk and juice were spiked and recovered.The recovery rate was between 93.84%and 108.80%,and the RSD was between 3.2 and 6.9.Based on the traditional indirect competition ELISA,this paper constructs a method based on bio-barcode immunoassay and CHA amplification technology to detect OTA,which is used for high sensitivity and rapid detection of OTA in food packaging.Compared with the traditional indirect competitive ELISA detection method,the immune bio-barcode achieves a highly sensitive detection of OTA.At the same time,the bio-barcode immunoassay has universal applicability for the detection of any small molecule target with antibodies,and the detection of toxin production in the process of food packaging has a good prospect of real application.