Define "microorganism."

Microorganisms are a collection of organisms that share the characteristic of being visible only with a microscope. Members of the microbial world are very diverse and include bacteria, cyanobacteria, rickettsiae, chlamydiae, fungi, unicellular (single-celled) algae, protozoa, and viruses.

Most microorganisms benefit humans. They maintain the balance of chemical elements in the natural environment, break down the remains of all that dies, and recycle carbon, nitrogen, sulfur, phosphorus and other elements.

Some species of microorganisms cause infectious disease and are called pathogens. Pathogens overwhelm body systems by sheer force of numbers, or they produce powerful toxins that interfere with body physiology. Viruses inflict damage by replicating within tissue cells, thereby causing tissue degeneration. Pathogens that cause foodborne illness include bacteria, viruses, and parasites.

If you have questions, contact Dr. Angela Fraser, Associate Professor/Food Safety Education Specialist, Clemson University, Clemson, SC.

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