Efficacy comparison of an automated growth-based system and plate-count method on the detection of yeasts and molds in personal care products.

Abstract

The present investigation studies the efficacy of an automated growth-based system for a quantitative determination of Candida albicans and Aspergillus brasiliensis in several personal care products. The main purpose of this validation study was to prove that the alternative method's entire performance is not inferior to the conventional pour-plate method for a quantitative determination of yeasts and molds. Thus, a performance equivalence was established in accordance with the United States Pharmacopeia <1223>. C. albicans and A. brasiliensis were pooled to use as inoculum (equivalent to 1.0x108 CFUs/mL) in the suitability of the method test. Personal care product's preservatives were chemically neutralized leading to the yeast's and mold's recovery by means of the alternative microbiological method and the pour-plate method. A correlation curve was generated for each personal care product by plotting DTs relative to the corresponding log CFU values. 30 personal care products have been tested for quantification of yeasts and molds using an alternative microbiological method. An equivalence of results were made through the construction of correlation curves that allow the establishment of numerically equivalent results between the enumeration data from the reference method and the alternative method. Thus, following the guidelines of <USP 1223>, essential validation parameters were tested, such as equivalence of results (CC > 0.95), linearity (R2 >0.9025), accuracy (% recovery >70%), operating range, precision (CV < 35%), ruggedness (ANOVA, P > 0.05), specificity, limit of detection, and limit of quantification. It was shown that all the test results obtained from the alternative method were in statistical agreement with the standard plate-count method. Thus, this new technology was found to meet all the validation criteria needed to be considered as an alternative method for yeast and mold quantification in the personal care products tested. Implementation of alternative methods can offer benefits in execution and automation while improving accuracy, sensitivity, and precision and reduce the microbiological process time compared to the traditional ones.