What does the phrase "food-borne illness" refer to?

Foods can serve as vehicles of many disease-causing and toxin-producing agents including bacteria, viruses, molds, and parasites. Viruses are not “alive” in the classical form. They need to get into cells to use the cell’s “machinery” to produce copies of themselves. Spores are the dormant state (similar to seeds) which some bacteria and molds can form to survive harsh conditions (such as cold or drought).

Microorganisms, whether they cause spoilage or disease, grow by increasing in number rather than increasing in size. Unlike spoilage microorganisms, which are usually apparent on the food (in the form of slime, discoloration, and/or odor), disease-causing organisms may not produce any noticeable changes (such as off-odors, off-flavors, or discoloration) on food.

Some of the bacteria that cause food-borne illness affect the human body via toxins they produce as they grow in food prior to being eaten by the person (for example, Staphylococcus aureus and Clostridium botulinum). Their effect is called food poisoning or food intoxication. These toxins can cause a bout of vomiting and diarrhea or be extremely serious, as is true of the neurotoxins produced by Clostridium botulinum.

Other bacteria produce illness by growing inside our bodies (for example, salmonella and E. coli). This process is called food infection. Some bacteria work via a combination of the two processes. They grow to high levels in the food, form spores in the digestive tract, and release a toxin that causes illness (Clostridium perfringens).

Source(s):

Susan Brewer, Ph.D., University of Illinois, Department of Food Science and Human Nutrition