The US Food and Drug Administration (FDA) has reported a confirmed positive sample of E. coli 0157:H7 in an open bag of spinach from a consumer who became ill in an outbreak of the bacterial disease that began 2 August.

While three manufacturers have already issued voluntary product recalls, this confirmed finding has helped narrow down the source of the contamination to California. Natural Selection Foods, the manufacturer that first issued a voluntary recall of spinach 15 September, manufactured the product in question.

One hundred and forty six people across 123 states have now fallen ill after eating spinach, the FDA said yesterday (21 September). This includes one death in Wisconsin and 23 cases of kidney failure.

E. coli O157:H7 is a potentially fatal bacterium that causes bloody diarrhoea and dehydration. Children, the elderly and people with weak immune systems are at the highest risk.

“We have turned out principal attention to the farms,” said Kevin Reilly, deputy director of prevention services at California’s Department of Health Services. “We are working with nine farms right now.”

For now the FDA is advising consumers to steer clear of fresh spinach, or products that contain fresh spinach, no matter where it comes from.