Applications of Sterilization
- Sterilization is used in the preservation of foods and liquids, such as canning and ultra-high temperature processing.
- It is crucial in medicine and surgery to ensure the sterility of surgical instruments, medications, and medical devices.
- Sterilization techniques are also employed in the sterilization of spacecraft components to prevent contamination of Solar System bodies.
- Sterilization is used to reduce initially present microorganisms or potential pathogens in various applications.
- The degree of sterilization is commonly expressed by the decimal reduction time (D-value), which indicates the time needed to reduce the initial number of microorganisms.

Sterilization in Food Preservation
- Nicolas Appert discovered that applying heat to foods and liquids slows their decay, leading to longer preservation for safe consumption.
- Canning of foods is an extension of this principle and has contributed to reducing foodborne illnesses.
- Other methods, such as ultra-high temperature processing, food irradiation, and high pressure sterilization, are also used in food preservation.
- Sterility in the context of food refers to commercial sterility, which means the absence of microorganisms capable of growing in the food under normal non-refrigerated conditions.
- The Codex Allimentarius provides guidelines for the distribution and storage of food to maintain commercial sterility.

Sterilization in Medicine and Surgery
- Sterility is essential in surgical instruments, medications, and medical devices that enter aseptic parts of the body or are used in parenteral pharmaceuticals.
- Steam sterilization is commonly used for medical and surgical devices, but low-temperature sterilization methods have become necessary for materials like plastics.
- Ethylene oxide gas has been used since the 1950s for heat- and moisture-sensitive medical devices.
- New low-temperature sterilization systems, such as vaporised hydrogen peroxide and peracetic acid immersion, have been developed in recent years.
- The United States Food and Drug Administration (FDA) requires a sterility assurance level of at least 10 for high-risk applications in medical devices and injections.

Sterilization in Spacecraft
- Strict international rules are in place to prevent the contamination of Solar System bodies from biological material from Earth.
- Sterilization techniques used in spacecraft components depend on the type of mission and its destination.
- Techniques like heating, chemical sterilization, oxidization, ultraviolet, and irradiation are employed, as many spacecraft components cannot withstand high temperatures.
- The requirements for sterilization become stricter for planets considered habitable.
- The goal is to prevent the introduction of microorganisms that could potentially survive and thrive in other planetary environments.

Quantification of Sterilization
- The aim of sterilization is to reduce the number of microorganisms or potential pathogens present.
- The degree of sterilization is expressed by the D-value, which represents the time required to reduce the initial number of microorganisms to one tenth of its original value.
- The D-value varies depending on sterilization conditions, type of microorganism, temperature, water activity, pH, etc.
- To ensure sterility, the overkill method is often used, which involves sterilizing for longer than necessary to kill the bioburden present.
- High-risk applications, like medical devices and injections, require a sterility assurance level of at least 10 according to the FDA.