Existing and potential applications of ultraviolet light in the food industry - a critical review

Short-wave ultraviolet light (UVC, 253 nm) can reduce dramatically the micr obial load in air or on hard surfaces free from food residues, and can elim inate pathogens from potable water filtered to remove organic residues and 'clumps' of bacteria. More recently, approval of the Food and Drug Administ ration (USA) has been sought for a system for the destruction of pathogenic bacteria in fruit juices using UVC, and the same approach could perhaps be applied to remove spoilage organisms from cider or wines. In contrast, lon g-wave UV light (UVA, >320 nm) has limited microbiocidal properties, and fo r practical applications its effectiveness has to be enhanced by the presen ce of photosensitive compounds (eg furocoumarins) that will diffuse into a microbial cell prior to irradiation. The penetration of UVA into water is b etter than that of UVC, and its bacteriocidal action in the presence of pho tosensitisers can be rapid. However, pure furocoumarins are expensive and t heir addition to foodstuffs might be questioned on safety grounds. (C) 2000 Society of Chemical Industry.