A magnetic fluorescent spirochetes micromotor: Dynamic monitoring and in situ sterilization of foodborne pathogens

Foodborne disease caused by foodborne pathogens is one of the most common, widespread and influential diseases in the world and poses a great threat to food safety and human health. It is worth noting that nondestructive detection and in situ sterilization of foodborne pathogens are of great significance for food nutritional retention. In this research, we constructed an aptamer fluorescent micromotor based on spirulina (SP) using aptamers as molecular recognition elements, nontoxic carbon quantum dots (CQDs) as fluorescent signal carriers, and polydopamine (PDA) as a thermal element to realize the accurate detection and in situ sterilization of pathogens in liquid food through the magnetic actuation of magnetized SP. It was proven that the detection limit of the aptamer fluorescent micromotor is 4 CFU/mL, the bactericidal rate can reach 100 %, and the detection recovery of the micromotor in milk samples is 92.89–106.96 %. In addition, the results showed that the protein retention rate of the micromotor after 30 s of near-infrared irradiation (NIR) was better than that of traditional pasteurization, which protected the food substrate as much as possible and provided great potential for practical application in food.