Bacteria are the most common cause of foodborne illness. Bacteria are found everywhere in our environment. Most species of bacteria are beneficial or do not cause illness. It is estimated that the few bacteria that do cause foodborne illnesses are partially responsible for approximately 30 million cases of foodborne illness yearly, with a mortality rate of approximately 10,000 yearly. Most cases of foodborne illness go unreported simply because the symptoms mimic those of common illnesses like the flu (gastrointestinal upset). The common symptoms are nausea, vomiting, and dehydration. Fever may or may not be present.
Bacteria can cause illness by two possible means:
Some bacteria can react to unfavorable changes in the environment, such as, heat and cold. These bacteria encase themselves in a protein coat, forming a spore. Spores can withstand heating and freezing processes. These bacteria are called spore formers. The Clostridiums and Bacillus bacteria are considered to be spore formers. Home canned goods and Honey are examples of food products known to occasionally be infected with spores.
Anaerobic bacteria thrive in environments with limited amounts of oxygen or no oxygen present. Foods that lend themselves to anaerobic bacteria growth are:
Clostridium perfringens and Clostridium botulinum are generally considered to be anerobic bacteria.
Aerobic bacteria require oxygen for growth. Listeria (reduced oxygen levels), E. coli, and Campylobacter are generally considered to be aerobic bacteria.
Facultative bacteria are those that can grow with or without oxygen. Unfortunately, most of the bacteria implicated in foodborne illness are facultative in varying degrees. Salmonella, Shigella, Staphylococcus aureus, and Bacillus cereus are generally considered to be facultative bacteria.
Bacterial requirements to support growth are:
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