A biological indicator is a device used to monitor the sterilization process for the standard population of bacterial spores. The biological indicators indicate that all the parameters necessary for sterilization were present. They are clear filter strips impregnated with bacterial spores and subjected to sterilization methods. They are tested for remaining presence of bacteria. The absence of bacteria in the final samples validates the method and determines sterilization accuracy levels. They are usually imbedded with bacteria that tend to be challenged by the sterilization process. In simpler terms, they are impregnated with bacteria spores that are difficult to kill. This indicates that all other bacteria present were also given the same treatment.
Great care is taken to minimize the chance of false positive readings which can cause expensive re-testing. Many government agencies from the FDA (Federal Drug Administration) to the Advancement of Medical Instrumentation (AMI) set standards for these biological indicators so that the medical profession can be sure their instruments are bacteria free and therefore safe to use. They ensure users of medical tools will not cause the death of patients while performing simple procedures.
The use of heat and fire dates all the way back to 1450 B.C. in the first pages of Leviticus, where god tells Moses to wash and burn the meat of animal sacrifices. It is said that ancient Greeks, would not wear wearing dirty clothes that touched open wounds because it could cause infection. They used fumes and burning chemicals for deodorizing and disinfecting purposes. In 460 A.D. to 377 B.C. Hippocrates of Con first separated philosophy and medicine, suggesting disease was not a punishment for sin. He advocated the irrigation of wounds with wine or boiled water, foreshadowing asepsis.
Galen (130-200 A.D.) a Greek practicing medicine in Rome, boiled instruments used in the caring of wounded romans. These ideas were not considered much in the Middle Ages where filth and pestilence led to plagues, ravaging all of Europe. Jumping to 1680 when Denyl Papin, a French physicist invented a pressure cooker called the digester. The digester was a pot with a tight lid. The pressure of the trapped air heated up to 15 psi from a boiling point of 212 degrees Fahrenheit to about 250 degrees Fahrenheit. The super-heated steam trapped inside, circulated around items placed inside, which quickly cooked them.
In 1683 Anton Van Leeuwenhoek, a linen draper that developed the microscope proved the existence of microorganisms. In 1758 Dr. Johann Julius formed surgical gloves out of sheep intestines that were used to deliver babies. In 1847 Ignaz Semmelweis, was a Hungarian that was accredited for advocating hand washing and fingernail scrubbing before any medical procedure. In 1867 Joseph Lister, an English physician, reduced the mortality rate of his patients by spraying articles and the hands of his operating team with a...