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. The common symptoms are nausea, vomiting, and dehydration. Fever may or may not be present. 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. Aerobic bacteria require oxygen for growth.