Effects of UV Irradiation on Penicillium Strains Isolated from a Bread Plant and the Application to Bakery Products

摘要

We tested treatement with UV irradiation for controlling the growth of bread mold. First, we analyzed the sterilizing effect of a dose of approximately 25 mJ/cm(2) radiation on nine Penicillium and two Talaromyces strains that were isolated from a bread-manufacturing plant. The P. chermesinum and P. paneum strains were sterilized completely at that dose, while it was only partially effective against P corylophilum. P. chrysogenum and P. decumbens were sterilized at a dose of approximately 120 mJ/cm(2), while T. amestolkiae was sterilized at approximately 150 mJ/cm(2). Sterilization of T. cecidicola and P. hispanicum required more than 200 mJ/cm(2) of radiation. These results suggest that UV resistance varies depending on the species and the strains. We also carried out UV irradiation of bread at 70 mJ/cm(2): a dose at which the taste of bread is not affected; we observed that mold growth was delayed visibly compared to the non-irradiated bread. These results suggest that UV irradiation at 70 mJ/cm(2) is effective at delaying mold growth, though it does not cause complete sterilization. This method should prove useful for extending the shelf-life of bread.