An Ultrasensitive Aptasensor For The Detection Of Aflatoxin And The Stability Research

The contamination of feed and food by aflatoxin B1(AFB1), one of the mosttoxic of the mycotoxins, is a global concern. To prevent food safety scares, and avoidsubsequent economic losses due to the recall of contaminated items, methods for therapid, sensitive and specific detection of AFB1at trace levels are much in demand. Inthis work, a simple, ultrasensitive, and reliable aptasensor is described for thedetection of AFB1. An AFB1aptamer was used as a molecular recognition probe,while its complementary DNA played a role as a signal generator for amplification byreal-time quantitative polymerase chain reaction (PCR). Under optimal conditions, awide linear detection range (5.0×10–5to5.0ng·mL–1) was achieved, with a highsensitivity (limit of detection (LOD)=25fg·mL–1). In addition, the proposedaptasensor exhibited excellent specificity for AFB1compared with eight othermycotoxins, with no obvious Ct value change. This aptasensor can also be used inquantifying AFB1levels in Chinese wildrye hay samples and infant rice cerealsamples, demonstrating satisfactory recoveries in the range of88–127%and94–119%,respectively. This detection technique has a significant potential for high-throughput,quantitative determination of mycotoxin levels in a large range of feeds and foods.Animals consuming AFB1contaminated feeds generate in their milk ahydroxylated metabolite of AFB1known as aflatoxin M1(AFM1)[1,2], AFM1has lowertoxicity than AFB1and is part of the secondary groups of carcinogenic compoundswhich have been classified by the IARC[3]. This study aimed to evaluate the stabilityof aflatoxin M1in raw milk under different storage conditions, such as storagetemperature and time, thawing temperature, freeze-thaw cycle times, and the additionof preservatives. Results showed the influence of all the different storage conditions,including storage temperature at4℃, storage temperature at-20℃, thawingtemperature, freeze-thaw cycle times, and the addition of preservatives wereinsignificant, demonstrating the satisfactory recoveries in the range of80–110%. Fewreports the stability and degradation rate of aflatoxin M1in raw milk up to now. Thiswork attempts to find out the optimal storage condition of aflatoxin M1in raw milkand make sure the accuracy of the results in milk safety monitoring.