The official definition of sanitizing for food product contact surfaces is a process which reduces the contamination level by 99.999% in 30 seconds.  The effectiveness of any chemical or process intended to destroy microorganisms depends upon several factors. Each of these factors demonstrate the importance of knowing the best conditions for the sanitizer you are using in order to reduce contamination to the fullest extent.

• Population size and composition - The types and numbers of organisms present will affect sanitizer activity.  Certain chemicals are more effective against specific groups of microorganisms, while others have a similar level of activity against most microbes.
• Antimicrobial agent concentration - As the concentration of the sanitizer increases, the activity does as well, up to a point.  Once a certain concentration is met, a leveling off occurs and increasing the concentration is no longer more effective.  Instead, a concentration that is too high can be corrosive to equipment.
• Temperature - Sanitizers generally have a temperature range in which they are most effective.
• Duration of exposure - Sufficient time is necessary to ensure the sanitizer had the desired effect. A longer exposure time is generally better.
• Local environment - Considerations include pH, surface characteristics, and the presence of inactivators and organic matter.  The pH can greatly reduce the sanitizers activity if not in the proper range.  In addition, the surface must be clean (you cannot sanitize an unclean surface) and free from crevices and other areas that might make cleaning difficult.  The presence of organic matter or detergent residue can also dramatically reduce effectiveness of a sanitizer.  Food product contact surfaces should be - rinsed  - cleaned - rinsed - sanitized.