Sanitizing vs Disinfection vs Sterilizing

Sanitizing

Sanitizing implies a 5-log kill rate for microbes (99.999% are killed), but their sporule forms can generally survive.

A note about cleaning:* you cannot properly or adequately sanitize a surface if it still contains any organic or inorganic deposits or films on it.

Example: spraying a clean, non-porous, food contact surface with prepared Star San, iodophor, bleach, or quaternary ammonium sanitizing solution.

Disinfection

Disinfection implies a 6-log kill rate for microbes (99.9999% are killed), but their sporule forms can generally survive.

Example: adding chlorine or chloramine disinfectant to drinking water, or preparing and wiping a non-porous surface with an undiluted iodophor or labeled chemical disinfectant. Pasteurizing foods and beverages with pH <= 4.5 is a form of disinfection.

Sterilizing

Sterilizing uses a different measurement method, requiring a sterility assurance level (SAL) of at least 10^-6 , typically, meaning that there is a one in a million chance if ANY SINGLE non-sterile unit (microbe or spore) has survived. A SAL of 10^-6 correates to around a 12-log reduction in microbes.

Example: heating equipment or wort to 15 psi and 240-250°F for 25-30 min in an autoclave or pressure canner explicitly capable of 15 psi.

Testing for Sterilization

The temperature and time needed to sterilize is tested with heat sensitive tape placed in the autoclave or pressure cooker.

The effectiveness of the methods and equipment can be tested with ampules of heat-resistant bacteria, which ampules are tested after the process with a color-changing dye.

The actual effectiveness of the sterilization (the equipment works, but did it sterilize?) can be tested by swabbing presumed-sterile surfaces and trying to grow microbes on an agar medium plate.

Created by /u/chino_brews, 2021-02-18