Sorbic acid used as preservative.  Very low level of toxicity, as rapidly metabolized (a fatty acid).  A few reports of contact dermatitis and pseudo-allergy only.

Similarly with Tartrazine, MSG, Benzoate – in most children, there is very limited evidence for any role of food additives in causing non-allergic food hypersensitivity. Reactions may be more common in children with chronic urticaria and angioedema.  While other symptoms including migraine, gastrointestinal disturbances and arthralgia have been attributed to food additives, there are no reproducible and consistent data from DBPC studies to support this.

Natural additives eg Annatto can also cause problems in some patients!

Sulphites (sulfites, eg sodium metabisulfite) and natural salicylates may cause skin (usually contact dermatitis, but can be angioedema), GI, respiratory problems (even anaphylaxis) but these are best termed adverse reactions as they have a pharmacological basis.  Patch and IgE test available, however.  Very common in our food – in fresh foods to control browning, soft drinks, dried foods (as preservative), wine and beer.  Yet very rare in childhood and therefore hard to spot.  Also seen in in anaesthetic solutions, antibiotics, adrenaline (!!!), cosmetics.  Sulphites can have effects when used topically, orally or parenterally – mostly seen in those with asthma.  Can be acute or chronic.  Given the problem with using adrenaline, may need to be treated with steroids, antihistamines, bronchodilators instead! [Clinical & Experimental Allergy. 39(11):1643-51, 2009 PMID 19775253]  

Salicylates are a large group of assorted foods and other things that can cause problems including anaphylaxis.  Natural salicylates are generally acetylated so no need to automatically avoid them if intolerance to aspirin/NSAIDs.

[PJ Turner, J Paeds Child health 2010]