The production of ochratoxin A by Aspergillus ochraceus and of ochratoxin A and citrinin by Penicillium viridicatum growing on previously sterilised barley for 200 days at 5,lO and 20°C and a water activity of 0.85 is reported. A . ochraceus did not grow at 5"C, multiplied slowly at 10°C but did not produce toxin. At 20°C the organism multiplied more quickly and produced ochratoxin after 19 days, which slowly disappeared over the next 150 days. P. viridicatum grew slowly at 5°C but did not produce any toxin. It multiplied at 10°C and produced ochratoxin A which was only detectable during the period from 100 to 150 days. At 20°C both ochratoxin A and citrinin were produced. Ochratoxin A was detected after 10 days and was still present after 240 days, whereas citrinin was produced in large quantities between 118 and 129 days and then rapidly disappeared.
Perennial ryegrass was inoculated with a mycotoxigenic strain of Fusarium roseurn or F. tricinctum and ensiled in laboratory silos to study the ability of the fungi to grow and produce toxin. Neither strain persisted in the silage or produced toxin. The addition of preformed toxin to the grass produced no detectable detrimental effect on the overall fermentation process.
A simple, rapid and quantitative method for the evaluation of radial growth and mycotoxin production by a number of toxigenic fungi on an agar substrate is described. A multiple inoculation technique permits the rapid inoculation of large numbers of fungal isolates which yield concentric colonies of reproducible diameter after 72 h incubation. No significant variation in the amount of toxin produced by colonies derived from replicate inoculations of the same fungus on different Petri dishes was detected. The reproducibility of toxin production by replicate colonies on agar was satisfactory and the efficiency of toxin extraction was not influenced by the concentration of toxin in agar.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.