Strain-Specific Synthesis of Mycophenolic Acid by Penicillium roqueforti in Blue-Veined Cheese.

Twenty of 80 strains of Penicillium roqueforti were able to produce up to 600 mg of mycophenolic acid (MPA) liter in 2% yeast extract-5% sucrose broth. Sixty-two of these strains had been isolated from the main blue-veined cheese varieties of western Europe or from starter cultures. Of these 62 dairy strains, only 7 had MPA-producing potential in vitro. These seven strains had all been isolated during the period 1975 to 1981 from the blue cheese of one individual factory. In cheese from the market, MPA (up to 5 mg kg) was only found in samples of this same factory. With MPA-producing and -nonproducing strains for the experimental manufacture of blue cheese, MPA synthesis in cheese was only detected with strains which form MPA in yeast extract-sucrose broth. The maximum MPA level at 4 mg kg was similar to that in commercial cheese. Toxicity of MPA was tested with two established human cell lines (Detroit 98 and Girardi Heart) and one established pig kidney cell line (AmII).

[A cell-culture assay for the detection of mycotoxins. I. Investigations with pure toxins (author's transl)]. / Ein Zellkulturtest für den Nachweis von Mykotoxinen I. Untersuchungen an Reinsubstanzen.

For the detection of mycotoxins by a biological assay cells were seeded in Microtiter-plates together with toxin. After 24 h and 6 days of culture cells were examined visually for cytocidal effects, growth inhibition, and morphological aberrations. Three human and 2 porcine cell-lines were compared as to their reaction with 16 mycotoxins and 9 organic chemicals. The results indicate that the toxin-activating systems differ with type and origin of cells. This suggests the use of several selected cell-lines in parallel for testing of microbially derived food additives for possible contamination by mycotoxins.