J. Cosmet. Sci., 69, 35–46 ( January/February 2018) 35 Use of L-Glutamic Acid in a New Enrichment Broth (R-TATP Broth) for Detecting the Presence or Absence of Molds in Raw Ingredients/Personal Care Product Formulations by Using an ATP Bioluminescence Assay YOUJUN YANG and DONALD J. ENGLISH, Avon Products Inc., Suffern, NY 10901. Accepted for publication December 4, 2017. Synopsis The present study reports the effects of adding L-glutamic acid to a new enrichment broth designated as R-TATP broth, to promote the growth of slow-growing mold microorganisms such as Aspergillus brasiliensis and Aspergillus oryzae, without interfering in the growth of other types of microorganisms. This L-glutamic acid containing enrichment broth would be particularly valuable in a rapid microbial detection assay such as an adenosine triphosphate (ATP) bioluminescence assay. By using this new enrichment broth, the amount of ATP (represented as relative light unit ratio after normalized with the negative test control) from mold growth was signifi cantly increased by reducing the time of detection of microbial contamination in a raw ingredient or personal care product formulation from an incubation period of 48–18 h. By using L-glutamic acid in this enrichment broth, the lag phase of the mold growth cycle was shortened. In response to various concentrations of L-glutamic acid in R-TATP broth, there was an increased amount of ATP that had been produced by mold metabolism in an ATP bioluminescence assay. By using L-glutamic acid in R-TATP broth in an ATP bioluminescence assay, the presence of mold could be detected in 18 h as well as other types of microorganisms that may or may not be present in a test sample. By detecting the presence or absence of microbial contamination in 18 h, it is superior in comparison to a 48–96 h incubation period by using either a standard or rapid detection method. INTRODUCTION All living microorganism contain and use adenosine triphosphate (ATP) as a vital part of their energy and metabolic system. Energy is stored within the phosphate bonds of the ATP molecule. By using a luminometer in an ATP bioluminescence assay, the presence of microbial ATP assay is used to detect light energy when ATP is converted to adenosine monophosphate (AMP) by an enzymatic reaction (1,2). This converted energy is detected as light energy and the amount of light is measured by a luminometer that is reported as a value of relative light unit (RLU). A higher RLU value corresponds to a higher level of ATP that is present in a test sample. A positive detection for a microbial contamination Address all correspondence to Donald J. English at don.english@avon.com.