A fresh vegetable foodstuff such as fruit, vegetables, grains or nuts is treated to reduce microbial contamination (UV-C irradiation, preferably in a CO.sub.2 atmosphere, preferably at -1 to +4.degree. C.) and/or to induce protective phytoalexins (UV-A, UV-B and UV-C irradiation) and/or to destroy aflatoxins (UV irradiation, primarily UV-C). A modular system can be readily adapted to different foodstuffs. It can include treatment modules and support modules (e.g. for cleaning elements of the treatment modules, providing them with controlled environments, and controlling the input of foodstuffs so they are susceptible to treatment).