Benzoic acid and benzoates are widely used preservatives against fungi. When added as preservatives, they should be labelled with the appropriate number (E210-215), or name (benzoic acid, benzoate). Hence you should read the product labels carefully. The only natural sources of benzoic acid are cranberries, which contain so much benzoic acid that they will hardly spoil. Thus cranberries and products made with cranberries should be avoided.