Model studies on the diffusion behavior of the mycotoxin patulin in apples, tomatoes, and wheat bread

Quantitative studies on the diffusion behavior of the mycotoxin patulin (Pat) performed by stable isotope dilution assays using a carbon-13-labeled analogue as the internal standard revealed that Pat did not diffuse into apples affected by the fungus Penicillium expansum. At a distance of more than 2 cm from the infected zone the mycotoxin was not detectable. However, in a similar experiment with tomatoes the mycotoxin was found to penetrate into the whole fruit. These different characteristics were related to the physical laws of diffusion and attributed to differences in the texture of the foods. Like in apple tissue, the patulin content in molded wheat bread crumb fell sharply at a longer distance from the fungal mycelium. A comparison with aflatoxins revealed that these mycotoxins show much faster diffusion into the crumb as compared to patulin.