Controlling Contamination
Since the recognition of ice as a source of microbial contamination, science has given us a better understanding of biofilm production and its control. Biofilms are a collection of microorganisms, mainly bacteria, growing together in a matrix of polymers secreted by the microorganisms. The associated slime formation is mold or fungus that accumulates from bacterial growth on surfaces constantly exposed to clinging water drops and warm temperatures. The biofilm may cause objectionable flavors and odors in ice. Once well-developed biofilms establish themselves on surfaces, cleaning and sanitation become much more difficult. Biofilms have a shielding effect on the bacterial cells that live within them. It is well known that normal cleaning and sanitizing methods may not control or eliminate biofilms, but rather they must be physically removed or prevented from forming on surfaces. For instance, Listeria can be 1,000 times harder to eliminate if it is living in a protective biofilm and can be a continual source of pathogenic and spoilage organisms if not completely removed.