CATERING FOR NUT-FREE DIETS
Nut allergy is usually of a severe, life-threatening type, where the sufferer will go into anaphylactic shock if given food containing the allergen. Many sufferers are highly sensitive, so great care must be taken to avoid any cross-contamination in the kitchen where meals are prepared, and also in the serving area for buffets.
Sufferers may be sensitive to any or all tree nuts, to peanuts (really a legume) or to seeds (eg sesame). NB This type of severe allergic reaction can also be triggered by other foods. For more information, visit:
http://www.allergyuk.org/peanut-and-tree-nut-allergy/peanut-and-tree-nut-allergy
Caterers: the site above states that vegetable oils containing the allergen should not be a problem. But I know of a case where a sufferer with soya allergy went into anaphylactic shock after being given food served with a spoon that had been in a dressing containing soya oil. So please take care with oils used and also to avoid cross-contamination from serving spoons.
A site which answers questions about coconut, nutmeg etc in relation to nut allergy: http://www.anaphylaxis.org.uk/what-is-anaphylaxis/faqs#2