Which chemical is not an approved sanitizing agent?

The reason delimer is not considered an approved sanitizing agent is that it is primarily used for removing mineral deposits and other types of buildup, rather than for sanitizing surfaces to eliminate bacteria and viruses. Delimers typically contain acids or other powerful cleaning agents that are used in situations where mineral buildup, like lime scale, needs to be addressed.

In contrast, the other options listed, such as chlorine, iodine, and quaternary ammonium compounds, are widely accepted and effective sanitizing agents used in food handling and preparation environments. These chemicals are specifically designed to reduce pathogenic organisms to safe levels on surfaces that come into contact with food, making them appropriate for sanitization purposes.