Sanitizers in Food and Water Microbiology — Among the following, which compound is classified as a surface-active agent (surfactant/detergent) used as a sanitizer for equipment and hard surfaces?

Introduction:
In sanitation programs for food processing, dairy, and drinking-water facilities, chemicals are chosen based on how they remove soils and inactivate microbes. Surface-active agents (surfactants) reduce surface tension, wetting equipment surfaces and helping lift organic films so that subsequent disinfection is more effective. This question checks recognition of which listed chemical is actually a surfactant used as a sanitizer/cleaner.

Given Data / Assumptions:

• We are comparing common names used in industry and older texts.
• Only one option is a true surface-active agent (detergent).
• Other salts listed act mainly as builders or sequestrants, not as primary surfactants.

Concept / Approach:

Surfactants possess hydrophilic and hydrophobic moieties that allow them to emulsify fats and disrupt microbial membranes (to a limited degree), assisting sanitation. Trade names like Teepol historically refer to synthetic detergents (for example, alkylbenzene sulfonates), widely used as wetting/cleaning agents prior to or along with disinfectants such as chlorine, iodophors, or quaternary ammonium compounds.

Step-by-Step Solution:

Verification / Alternative check:

Sanitation protocols commonly use a detergent (surfactant) wash step followed by rinsing and then a disinfectant. Product data sheets for Teepol-type detergents emphasize wetting, emulsification, and cleaning of stainless steel and polymeric surfaces in dairies and breweries.

Why Other Options Are Wrong:

A: Tetra phosphate is a builder that sequesters hardness but is not a surfactant. C: Metaphosphate acts similarly as a sequestrant/water softener. D: Incorrect because a valid surfactant (Teepol) is listed. E: Quenched lime is an alkali, not a surfactant.

Common Pitfalls:

Confusing “builder” salts with “detergents.” Builders improve surfactant action but do not replace the amphiphilic molecules that provide wetting and emulsification.

Final Answer:

Teepol (synthetic detergent/surfactant)