Fears surrounding the GM corn StarLink have led to the cessation of operations at a Kansas mill, following the possibility that its production facilities have been contaminated. The mill is owned by ConAgra Foods, one of the largest packaged-foods companies in the US, and it has revealed that shipments of corn flour will not resume until the facility has been completely cleared out and its inventory is tested.

Company spokeswoman, Karen Savinski, commented: "We're doing this as a precautionary measure." She declined, however, to explain why officials thought the mill may be at risk, and which products may be contaminated.

The Kansas mill is the second in the US to be disrupted by the presence of StarLink, which has been designed to produce its own insecticide and has not been approved for human consumption. Its French pharmaceutical producer Aventis has stopped sales of the seed and has attempted to buy up all the crops harvested to date, but the 315,000 acres of cornfields in question are scattered widely and make all surrounding mills and fields prone to contamination.

Mexico's largest corn producer, Gruma, controls two US units, Azteca Milling and Mission Foods, and each has been affected by GM corn concerns. Azteca's milling facility in Texas was closed for yellow corn products late September following the Kraft taco shells debacle, and several problems have since arisen. The Azteca mill supplied flour to sister company Mission Foods, where it was used to make taco shells to be sold under private supermarket labels, and independent tests claimed to prove that these too were contaminated.

On 11 October, the largest US supermarket chain Safeway implemented a voluntary recall following allegations that its own brand of taco shells were contaminated, and other retailing chains, including Shaw's Supermarkets and Food Lion, have since followed suit. Mission Foods' executives maintain that they do not understand how contamination could have occurred.

Last week, both Azteca and Mission Foods announced that all yellow corn products from their milling facilities would be recalled, including taco shells and tortillas. They will focus on milling white corn products while investigations into StarLink continue.