Antimicrobial activity and stability evaluation of soap from caprine milk, yogurt, and kefir

Abstract

Caprine milk is a nutraceutical source with various benefits for human health. The content of bioactive peptides in caprine milk has biological functions as an antioxidant, anti-inflammatory, and antimicrobial. Based on the benefits of caprine and its dairy products, we utilized them as the main ingredient for soap formulation. Stability evaluation is important to determine the shelf life and safety of the soap. This study aimed to examine the effect of different temperatures and storage time on the physical characteristic, pH level, heavy metal contents, and the antimicrobial activity of the soaps. We showed that the color and aroma of the soaps were relatively stable with a minor change in their hardness levels. The level of pH for all samples was around 7,00–8,70, which could be safely used on human skin. The level of heavy metal including Cd, Pb, and Hg were below the maximum standard allowed for the soap products. A little increase in the number of bacteria colonies were found when the soaps were stored at the longer durations. Based on the physical stability, pH level, heavy metal contents, and antimicrobial activity, these soaps might be safe for application on human skin.