On-site tracking of trace Aflatoxin B1 in food waste composting via a portable colorimetric sensing platform with nanozymes

Abstract

Rapid, on-site accurate tracking of harmful mycotoxin in food waste composting is essential to provide instant content information for efficient supervision. However, on-site analytical tools especially colorimetric sensors currently suffer from low sensitivity/selectivity and poor environment robustness, posing hurdles for their applications. In this work, we have proposed a portable paper-based colorimetric sensor to detect the representative mycotoxin (aflatoxin B1, AFB1) in the composting process, where the superior catalytic velocity (6-fold higher than the natural enzyme) and well-regulated catalytic activity of nanozyme by the aptamers ensure the high sensitivity (a wide linear range: 0.1–1000 ng/mL; an ultra-low limit of detection: 0.082 ng/mL) and good selectivity of the colorimetric sensing, respectively. The smartphone-based platform exhibits high accuracy with the relative standard deviation within 3.67 % compared commercial enzyme-linked immunosorbent assay. Finally, on-site tracking of the AFB1 content in food waste during the composting process with or without the oxidant (potassium persulfate) has been carried out using the developed colorimetric sensor. It is concluded that reducing the AFB1 generation in the food waste is more meaningful than the compost treatment. This study offers a promising method for in situ analysis of trace AFB1 in food waste compost to ensure environmental and human health safety.