Wax is used as treatment, coating, laminate and impregnation of primary food contact materials such as paper, board, aluminum. It is used as a lubricant to reduce friction in the manufacturing process [1]. It may also be used to coat food directly, such as in the case of fruit and cheese, in which case it is edible [1, 2] Waxes may be petroleum based such as paraffin waxes or made of natural material such as beewax, soywax or candelilla wax.
Paraffin waxes are a solid mixture of saturated hydrocarbons. They may be mixed with small PE molecules to modify melting points. UV light and heating can lead to the degradation of waxes. Consequently, some antioxidant may be added to improve the functionality. Further, plasticizers and water proofing agents might be added [1].
Waxes are used in food packaging materials because they have good moisture barrier characteristics. As such they can protect dry foods from environmental moisture or reduce moisture loss of the food stuff [3]. Further, a wax coating may protect food stuff during transport and handling.
Yet, there is concern that waxes and their other components may migrate into food stuff, particularly if they are part of the food contact layer. A study by Varner et al. showed that it was possible to measure benzophenone in paraffin waxes used in food contact materials, but no migration studies are available to this point [4].
Food contact materials are regulated under the EU Framework Regulation EC 1935/2004 on materials and articles intended to come into contact with food. In principle waxes can be regulated under this framework. Waxes that are part of a polymer material or made from polymers themselves are regulated under EC 1282/2011 on plastic materials. Yet, for all other food contact materials no specific regulation on waxes has been enacted in the EU.
In the US, waxes used in food contact materials are regulated in the Code of Federal Regulations,Title 21 on food and drugs, part 174 to 180. As such, paraffins (synthetic) are authorized as adhesives and coatings in §175.250 (21 C.F.R. 175.250) with certain specifications. Petroleum waxes, synthetic petroleum wax and reinforced wax are permissible in food contact materials as adjuvants, production aids and sanitizers if they meet certain specifications including a ultraviolet absorbance limit (CFR, 21, 175.3710/3720/3850).
References
1. Parisi, S., Food packaging and food alterations: the user oriented approach. Shawbury: Smithers Rapra. 392
2. Appendini, P. and J.H. Hotchkiss, Review of antimicrobial food packaging. Innovative Food Science & Emerging Technologies, 2002. 3(2):113-126.
http://www.sciencedirect.com/science/article/pii/S1466856402000127.
3. Riederer, M. and L. Schreiber, Protecting against water loss: analysis of the barrier properties of plant cuticles. Journal of Experimental Botany, 2001. 52(363):2023-2032.
http://jxb.oxfordjournals.org/content/52/363/2023.abstract.
4. Varner, S.L., H.C. Hollifield, and D. Andrzejewski, Determination of benzene in polypropylene food-packaging materials and food-contact paraffin waxes. Journal – Association of Official Analytical Chemists, 1991. 74(2):367-374.
http://europepmc.org/abstract/MED/2050616.
