Rapid detection of nitrite and Listeria monocytogenes in food based on multiple simulated enzyme activities of Fe3O4-ZnO-MnO2 nanocomposites

Food safety has emerged as a paramount concern in global health, prompting innovative approaches to ensure the safety of people's sustenance. In this study, a novel strategy was devised to fabricate Fe 3 O 4 -ZnO-MnO 2 hybrid nanobiocatalysts, which exhibited remarkable enzymatic activity surpassing that of Horseradish peroxidase (HRP) catalysis. It demonstrated exceptional proficiency in decomposing 3,3′,5,5′-tetramethylbenzidine (TMB) without the need for harsh reaction conditions or the aid of H 2 O 2 . We established colorimetric detection systems based on Fe 3 O 4 -ZnO-MnO 2 -TMB both for nitrite (NO 2 − ) and Listeria monocytogenes (LM) in food. Impressively, the detection limit of nitrite reached an astonishingly low level of 0.022 mg L −1 , and the detection limit for LM was determined to be 3.5 cfu mL −1 . These compelling results unequivocally validate the potential of these hybrid nanobiocatalysts to fortify food safety measures. Moreover, they serve as a valuable reference for the colorimetric detection of diverse analytes and the simultaneous detection of multiple targets.