The subject of natural preservatives probably has more academic interest than practical or economic virtue. However, it does have a wonderful marketing angle that may justify the higher raw material costs.
This paper looks at the most commonly used methods of preservation that are already available to the formulator. It also conceptualizes the theoretical development of a natural preservative system using a database on medicinal plants as a source of reference. The legal aspects of this concept in Europe are considered. The traditional methods of preservation - many taken from the food industry - are summarized. The use of alcohol, glycerine, sugar, salt, dessication, anhydrous systems and temperature are amongst examples considered. The commercial solutions are examined.
Regulatory Position: Annex VI
According to European regulation, the only permitted preservatives are those that appear in Annex VI Part 1 or 2 of the EEC Cosmetic Directive 76/768/EEC, including the 7th amending Commission Directive 94/32/EC.
However, there is no legislation for those natural materials, which, when used for their benefi cial effect on the skin, may coincidentally have a positive effect on the total preservative requirement of the formulation. Of course, no material appearing in Annex II may be considered for use.
The food industry often uses a preservation technique known as the “hurdle approach,” where there are a number of different methods that might eliminate organisms on their own if used at a high level, but which in a food might make the product unpalatable. The idea of using a whole variety of these “hurdles” to slowly weaken each organism, but at individual levels that would be ineffective, is an almost alien concept to the cosmetic and toiletry industry.
Sugar: High levels of sugar can preserve against spoilage organisms. This may be seen in jams, preserves, certain sweet pickles and marmalades. This is also an important factor in the preservation of boiled sweets and chocolates.