Reactions to food additives

The purpose of a food additive is to make a food look, taste or stnell better and to improve its texture or keeping qualities. Labels must indicate the presence of colouring agents, preservatives, antioxidants, emulsifiers, stabilizers, sweeteners and a number of other agents. Code numbers have therefore been issued with the prefix 'E' if the substance has been approved by the European Community. The main categories are as follows: keeping properties, i.e. preservatives, antioxidants, acidity regulators (E200-321); food appearance, i.e. colours (El00-180); and modified consistency or texture, i.e. emulsifiers, stabilizers, thickeners, sweetners (E322-495). Because of the occasional development of adverse reactions to some of these substances (probably affecting less than one in a 1000 people) [1], unrealistic campaigns have been mounted to exclude them all. Without them, neither a common loaf of bread nor a bottle of wine could be produced. While they have a substantial safety margin for the general public, however, a few substances can undoubtedly cause problems for some individuals. The mechanism is unknown but seldom seems to involve IgE. The sulphiting agents have been invaluable in preventing the oxidation of the oils and fat in food and in preventing the discolouration which results from enzyme effects, but they can cause adverse reactions in some circumstances, including flushing, itching of the mouth and skin, and asthma. About 5% of those with asthma can have an attack provoked by sulphites, to a degree which can be life threatening [2]. Their use in 'fresh' fruit and vegetables has now been banned in the United States but substantial quantities are present in wine and other drinks, in shrimps and processed potatoes, and even in some nebulized drugs. Adverse effects are also seen with nitrites, which give preserved meats their pink colour but can also cause flushing and giddiness through their vasohdating effects. Sodium nitrite can be encountered in food in amounts of 20mg, which can cause headaches, skin rashes, and gastrointestinal symptoms [3]. The antioxidants butylated hydroxyanisole and butylated hydroxytoluene can aggravate urticaria in occasional cases [4]. Benzoates and sorbic acid can do the same or