Monsanto has responded to further threats to its Roundup glyphosate-based weedkiller product.
US regulators may start testing food products for residues of glyphosate, the US Environmental Protection Agency (USEPA) has said.
A research unit of the World Health Organization reported in March it was classifying glyphosate as "probably carcinogenic to humans."
The herbicide is considered safe by the USEPA and many foreign regulatory agencies. The US government does not currently test for glyphosate in food, but has said: "Given increased public interest in glyphosate, EPA may recommend sampling for glyphosate in the future."
Monsanto has posted a blog to reassure consumers about glyphosate residues.
In March, the International Agency for Research on Cancer (IARC) - the cancer evaluation arm of the World Health Organization - linked glyphosate to cancer.
Monsanto business director Gary Philpotts said of the Germany-based Federal Institute for Risk Assessment (BfR): "The BfR, the EU member state 'Rapporteur' for the glyphosate renewal process, say they were 'surprised' by IARC's findings, which appear to be based on a "more or less arbitrary selection of studies. BfR's confirms its opinion is that 'glyphosate is unlikely to pose a carcinogenic risk'."
The HTA advises glyphosate is 'effective' and poses 'no real danger'. The BfR recommended those involved in the assessment of glyphosate should resolve the discrepancies, before the EU-Commission makes a decision on the further approval of glyphosate.
Glyphosate residues - Monsanto response
On the issue of glyphosate residues, Philpotts referred to Monsanto senior toxicoligist Kimberley-Hodge-Bell's blog last month that stated: "The USEPA conservatively sets the acceptable daily intake from all food and water sources at least 100 times lower than levels that have been demonstrated to cause no effect in animal testing. In May 2013, the USEPA found that all glyphosate exposures through food crops and water sources were no more than 13 per cent of the acceptable daily intake based on a highly conservative assumption that all crops are treated with glyphosate and carry maximum allowable levels."