KEY WORDS Natural preservation, traditional preservation, challenge test organisms, legal status.
INTRODUCTION The subject of natural preservatives is one that probably has more academic interest than practical or economic virtue. However, it does have a wonderful marketing angle which may justify the higher raw material costs. The paper first reviews the most commonly used methods of preservation that are already available to the formulator. The food and beverage industry may be called upon for many of these examples. Secondly, the paper moves on to consider the search through the existing data and considers the problems of commonly used synonyms for the act of preservation.
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Finally, the author looks at some specific organisms commonly encountered in the cosmetic and toiletry industry and gives examples of some of the plant references.
LEGAL POSITION No preservative may be used which does not appear in:Annex VI Part 1 or 2 of the EEC Cosmetic Directive 76/768/EEC - including 7th. amending Commission Directive 94/32/EC. However, there is no legislation for those natural materials, which, when used for their beneficial 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.
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 etc. Increasingly, it will be noticed that many products now have to be kept in the refrigerator of freezer once opened, because sugar has been replaced by artificial sweetener which is cheaper and healthier(?) to eat, but which compromises the self-preservation of the product.
HONEY Honey in its undiluted form is also a natural preservative and, indeed, there are many learnéd papers citing honey as a viscous barrier to bacteria and infection.
ALCOHOL Not all organisms are bad! The production of alcohol from sugar by yeast is an industry in its own right. A wine carefully produced using sterilised equipment and fermented to 13% by volume will just about resist further infection from external organisms, once the ferment has completed. It is during the time of the fermentation process that the fermenting must is vulnerable to infection. The naturally produced fermentation grade alcohol can be concentrated by...