Final answer:
Fluorine is not a chemical sanitizer used in food service; instead, iodine and chlorine are commonly used due to their effectiveness and safety at appropriate concentrations.
Step-by-step explanation:
The chemical sanitizer that is not used in food service amongst the options provided is fluorine. Fluorine is a halogen but is largely considered too reactive for general use as a sanitizer in food service applications and can pose significant risks to health. Instead, other halogens such as iodine and chlorine are commonly used. Iodine is used in various forms, including iodophors like povidone-iodine, for its antimicrobial properties. Chlorine is used as well, particularly in the form of sodium hypochlorite (household bleach) or chloramines, which are effective against a wide range of pathogens.
Additionally, chlorine compounds like hypochlorous acid are utilized for water disinfection in municipal drinking water and swimming pools. Oxygen, listed as an option, is not typically categorized as a chemical sanitizer in the context of food service applications and microbial control. However, it can be involved in certain oxidative processes that can disinfect.
While not a traditional chemical sanitizer like chlorine or iodine, oxygen can play a role in disinfection through oxidative stress in microbial cells, but other methods of disinfection (like autoclaving or use of specific oxidizing agents) are more commonly employed.