Use of materials incorporating microparticles for avoiding the proliferation of contaminants

A method for preventing, limiting and/or eliminating contamination of a solid material, and/or contamination of a composition that is in contact with said solid material, for at least a given time, and/or for preventing, suppressing and or slowing-down biofilm formation on a surface of the said solid material, comprising forming a solid material comprising a matrix and a set of individualized microparticles uniformly distributed within the matrix comprising or consisting of at least one antimicrobial agent, wherein the antimicrobial agent is a bactericidal or bacteriostatic agent which is an oxide of at least one positively charged metal ion and where the antimicrobial agent does not migrate out of the solid material,

• and wherein:
• the microparticles have a mean diameter between 0.5 micrometres and 5 micrometres, determined by microscopy;
• said microparticles have specific areas greater than or equal to 15 m2/g, as measured according to the BET method;
• at least 80% of the microparticles in the set have a sphericity coefficient of 0.85 or more, and at least 90% of the microparticles in the set have a sphericity coefficient of 0.75 or more;
• the concentration of said microparticles is 0.1 to 10%, by weight, based on the weight of the matrix and particles;
• the individualized microparticles are formed of at least two crystallites and are not composed of an aggregate of several smaller particles;
• and
• the individualized microparticles are non-aggregated within the matrix.