Abstract: An in-situ microbial contaminant detection system provides a chemical reagent within a liquid health care product or in close association with product packaging containing the health care product. The chemical reagent interacts with a variety of microbial contaminants or byproducts, such as enzymes and acids, of the microbial contaminants that are commonly found in health care products (e.g., P. cepacia, S. marcescens, E. cloacae, E. gergoviae, E. aerogenes, K. pneumoniae, and P. aeruginosa) and provides a visible indication of microbial contamination that can readily be discerned by a consumer. A color change is preferred.