A German microbiologist believes New Zealand's vets need examine our dairy cows immediately to see whether the botulism contamination may have come from infected animals.
The German dairy industry has experienced a large increase in the number of botulism outbreaks in cows since the mid 1990s.
Professor Monika Krueger of Liepzig University believes the outbreaks there are related to the practice of feeding glyphosate-drenched genetically engineered crops to cows.
She said glyphosate kills off good bacteria, allowing bacteria like the ones which cause botulism to thrive.
Botulism is not believed to be a problem in New Zealand livestock and Fonterra says the spores came from a dirty pipe.
While she is not familiar with conditions in New Zealand, Professor Krueger said the authorities would be foolish to just look in one direction.
She said vets should be checking cows now - to see if they were the source of the spore which made its way into Fonterra's plant and product.
Professor Krueger said the urine of cows should also be investigated for traces of glyphosate.
While Waikato University agribusiness professor Jacqueline Rowarth has not seen Professor Krueger's research - she does not believe GE feed led to Fonterra's contamination.
"I think it's highly unlikely. New Zealanders have been using Round Up for pasture renewal for years, we spray out pasture and put in new cultivars or we put in crops; and if there had been a problem with clostridium botulinum letting the spores get through I think we would have noticed it by now."