Parabens

Parabens are preservatives based on the lower alkyl esters of p-hydroxybenzoic acid and their respective sodium salts, which have been used extensively for many decades for the preservation of cosmetics & personal care products, pharmaceuticals, and some categories of foodstuffs (in line with current national food additive regulations).

All paraben grades have intensive growth-inhibiting effects on mold fungi, yeasts, and bacteria. The choice of grade therefore depends mainly on the composition of the finished product to be protected. Products containing sugar and starch, for example, are attacked chiefly by mold fungi and fermentative yeasts.

If they have an acid reaction, they are not usually attacked by bacteria. Bacteria mostly occur in products with a neutral reaction, especially if these contain proteins. Most species of bacteria are far more resistant to preservatives than mold fungi and yeasts. For this reason, protection against bacterial decomposition always requires a higher addition or combination of parabens.

Parabens not only inhibit the growth of microbes, but they also kill them if used in sufficient concentrations and allowed to act for a long enough period of time. Thus the germ count in substances preserved with parabens steadily decreases, a factor which is of great practical importance for cosmetic and pharmaceutical products. It must be borne in mind that raw materials, intermediates, and finished goods can no longer be reliably protected from parabens if they have already become heavily infested with germs.