On the 26th March 2006 The Western Mail newspaper published an article featuring Professor Derek Knottenbelt
"He said the poisonous pyrrolizidine alkaloids (PAs) contained in ragwort could spread to humans through several routes ............ In South Africa they had been found in bread, possibly through ragwort growing unseen among crops and being included in the flour."
However, the South African National Biodiversity Institute which includes their National Botanic Garden says there are no specimens of this species in their herbarium apart from a few from Europe and it appears to be unknown there, and the example from the literature shows that it was a different set of plants that were responsible under the agricultural practices of nearly a hundred years ago.
See also an account of a letter with similar claims that Professor Knottenbelt wrote in the Yorkshire Post for more comprehensive details.