Many processed foods do not need preservatives or are not permitted to contain them because the method of processing performs the same task as the preservatives. For example, canned foods, pasteurised and UHT milk, and frozen fruit and vegetables do not need added preservatives. If preservatives are used, their presence must be declared on the label. The most widely used preservatives are various forms of sulphur dioxide (220, 221, 222, 223, 224, 225 and 228), benzoic acid (210, 211, 212, and 213), sorbic acid (200, 201, 202 and 203) and propionic acid (280, 281, 282 and 283). They are commonly used in foods such as bread, soft drinks, dried fruits, fruit juices and drinks, and sausages. The use of benzoic acid and sulphur dioxide and its derivatives has caused allergy-like reactions in some individuals.