Plant Preservative Mixture, also known as PPM, is a powerful biocide against waterborne, endogenous contamination, airborne, fungal contamination and human contact. It is a liquid solution that prevents and reduces microbial contamination in plant tissue culture, and it is an excelent replacement of the antibiotics. It targets and inhibits multiple enzymes, the formation of resistant mutants towards PPM is unlikely. It is used both as a biocide and biostatic compound as a preventative measure.