Cosmetics and toiletries are not only under attack from microbes, but they can also deteriorate when exposed to bright daylight and oxygen from the air. UV absorbers are added to protect cosmetics from the effect of light, and antioxidants (as the name suggests), protects the product from the detrimental effects of oxygen.
When butter or cooking oil goes rancid we might assume that it had been infected with an unwanted microbe, in a similar way to the microbes that cause bread to go moldy or milk to go sour. However, this is not the case. Fats and oils seldom become infected with bacteria or fungi.
- Antioxidants block this chemical reaction and prevent the breakdown of cosmetics ingredients. Some Antioxidants are also used as food additives to preserve the fats and oils present in pre-cooked foods. Both citric acid and lactic acid can improve the efficiency of antioxidants, allowing smaller quantities of these to be used in the product.