A03024/25: Collation and review of information on the use of unusual and non-traditional types of wood used as food contact materials
Wednesday 18 June 2003
This research project aims to gather information on the use of unusual and non-traditional types of wood as food contact materials and investigate which chemicals could migrate into food from these.
Study Duration: September 1999 to January 2002
Contractor: Leatherhead Food International (formally Leatherhead Food Research Association) and TRADA Technology Ltd
Background
Wood, such as oak and pine, has traditionally been used as a material intended to come into contact with foodstuffs, for example for their storage, transportation and in culinary and kitchen activities. However, the uses of unusual and non-traditional woods for food contact have become more common, it being suggested that decorative and aesthetic properties of these products have added to their popularity. Currently there appears to be little available compiled information regarding the identities and levels of substances present in unusual and non-traditional types of wood. Neither is there much drawn together on substances that are added to these woods in the form of coatings, surface additives or preservatives, which have the potential to migrate into foodstuffs.
The current project has been carried-out to review and collate information on the chemical properties and present day uses of wood, in particular unusual/non-traditional or exotic woods for food contact applications in the UK. From this knowledge of the extent to which wood is used in contact with food, it was proposed to assess the potential for migration of the chemical constituents, of such wooden items, and substances added to these items as coatings, surface additives or preservatives.
Research Approach
To meet the above needs the project has;
- Reviewed published literature on wood species.
- Conducted a market survey of the uses, and reasons for use, of wood for food contact in the industrial/retail sector and domestically.
- Carried out analytical testing on woods, identified in the market survey to be used in the manufacture of food contact materials and articles – and including those identified in the literature as having natural toxic properties, together with relevant commercial coatings and finishing products.
The first part of the study consisted of an intelligence-gathering exercise on the species of wood used in direct contact with food. It addressed, in particular those items derived from non-traditional or exotic type woods. Leatherhead Food Research Association (LFRA) and TRADA, another research organisation, obtained information, from databases and published research papers, articles and other technical information.
A market survey was conducted to identify the use of wood (including unusual woods) for food contact in the industrial/retail sector. Two questionnaires were designed to establish the type of material or article; the species of the wood; any coatings/treatments that may have been applied to the finished products, and the nature of contact with foodstuffs. They were used in surveys that also investigated the factors that may influence decisions to use wooden food contact materials, and to obtain information on the use of unusual wooden food contact material/articles within the home environment. Four focus-group meetings were held at different regional locations in England and Wales. Quantitative data was obtained via a questionnaire, which was completed by the meetings’ participants. This questionnaire was also widely distributed to consumer organisations.
Analytical screening of different wood types used in the manufacture of food contact articles was carried out. This included samples of uncoated wood (identified in the literature as having natural toxic properties) available to the woodcraft industry for manufacture into items that may be used in contact with food. It also included samples from retail outlets of coated, finished wooden food contact articles.
Results and findings
Many scientific studies have been undertaken to identify and characterise constituent natural substances of wood. Some species of woods are known to contain ‘naturally occurring toxic substances’. Some poisonous effects from direct ingestion of these woods have been reported in animals and humans. However, currently there is very little published information available on levels, and the potential for transfer and migration of chemical substances, including natural toxicants, from finished wood products to contact food.
Wood products are used in domestic situations in direct contact with food for culinary and kitchen activities. They do not appear to be extensively used for commercial food preparation environments.
The use of 'exotic' and non-traditional woods (from areas such as 'cottage' and ‘craft’ industries and as gifts from overseas) for food contact appears to have increased recently. Physical and aesthetic characteristics influence the choice of wood species used for such articles rather than issues of food safety and quality. In many cases, the end-user is not aware of the species of wood used.
A wide range of timber from different wood species is used to manufacture decorative and functional objects such as kitchen utensils and bowls. Coatings and finishing products, of various formulations, are often applied to the finished wooden articles. Four examples of these products were analytically investigated by solvent dilution. This identified aromatic hydrocarbons (as xylene isomers) in two of these products. The extent to which these coating and finishing substances are used with wooden food contact materials and articles is unknown, however.
As part of this project analytical screening has identified a number of volatile and solvent-extractable compounds from woods typically used in food contact situations within the UK. The literature survey identified natural toxicants present in woods, such as taxine in yew, prunasin in cherry wood, and naphthoquinones in American black walnut. The analytical methods used would be expected to identify such toxicants, but none were detected.
Dissemination information
Final report is available from the FSA Library and Information centre. To obtain a copy, please contact the Enquiry Desk, Dr. Elsie Widdowson Library and Information Services, Food Standards Agency (020 7276 8181/8182 or at library&info@foodstandards.gsi.gov.uk).
See Also