Why are preservatives necessary in cosmetic products?

Preservatives are crucial in cosmetic products primarily to prevent microbial contamination. When cosmetic products are exposed to air, moisture, and environmental factors, they can become breeding grounds for bacteria, mold, and yeast. This microbial growth not only compromises the integrity and safety of the product but can also lead to skin irritations or infections when applied to the skin.

Preservatives help to extend the shelf life of cosmetic products by inhibiting the growth of these unwanted microorganisms, ensuring that the product remains safe and effective for consumers throughout its intended use period. Without proper preservation, products would be at serious risk of contamination shortly after opening, which can have detrimental effects on users' health and the overall quality of the product.

The other provided options address different aspects of cosmetic formulation. For instance, while giving a desirable scent and enhancing color can improve the sensory experience and appeal of a cosmetic product, they do not provide any protection against microbial contamination. Likewise, increasing viscosity may improve the texture or application of a product, but it does not serve the vital role of preserving the product's quality and safety. Thus, the primary function of preservatives is to safeguard against microbial threats, making them an essential component in cosmetic formulations.