what is an example of a microorganism acting in a harmful way?
Others cause spoilage. And, a small number are pathogenic (or harmful) and so can cause disease, such as foodborne illness. Three types of microorganisms can contaminate food and cause foodborne illness â bacteria, viruses, and parasites. Another group of microorganisms that one also needs to be concerned about are fungi, which are yeast and molds. Yeast and mold cause food to spoil but do not cause foodborne illness.