The present invention provides compositions and methods for reducing microbial and nematodal contamination or infection in plants, animals, fabrics, and products therefrom. The present invention also provides compositions and methods for reducing human infections and the emergence of antimicrobial resistance. In particular, the invention provides magnetic nanoparticles comprising biocidal or biostatic enzymes in one component, substrates for the enzymes in a second component, and a biocidal chemical agent that works in combination or synergistically with the enzymes. The compositions are dormant and become active upon exposure to hydration, oxygen, or mixing.
