It is quite possible that the days of moldy fruit have come to an end. Researchers at the Max Rubner Institute (formerly the Federal Research Center for Nutrition and Food) in Germany have discovered that certain wavelengths of visible light disrupt the rhythm of life of many forms of mildew so successfully that they stop producing fungal toxins. Ochratoxins are the toxins of a large group of mildews that also include various penicillium and aspergillus species. Like most living organisms, these molds have a biological clock that regulates growth and metabolism. At the beginning of the project, professor Rolf Geisen, a researcher at the institute, suspected that “if we can manage to change the rhythm of this clock, then we can stop the production of toxins.” Researchers at the Max Rubner Institute inhibit the production of toxins. (Image: Joachim E. Röttgers) According to the researchers, blue light with a wavelength of 450 nm has proved to be a particularly effective inhibitor. “We don’t use harmful UV radiation. The blue light is sufficient to destroy 80 percent of the mold spores,” said Dr. Markus Schmidt-Heydt, a researcher on Geisen’s team. On the other hand, researchers have also discovered that yellow and green light promotes the growth of the molds. Molds are therefore certainly not "blind." They have light receptors for different wavelengths. Unfortunately, however, the varieties of mold have different levels of sensitivity. Typical cereal molds like the fusaria react differently to being illuminated, producing higher levels of light protection pigments like carotin, for instance. This discovery is being intensively tested for its practical application in the context of the EU project “Novel strategies for worldwide reduction of mycotoxins in foods and feed chain” (MycoRed). If the illumination strategy meets its promise in the practical testing stage, the institute's findings would be considered a huge step forward in the battle against the spoilage of food in Germany and throughout the world. For more information, visit: www.mri.bund.de