Sainsbury's, Britain's third-largest supermarket, said it was carrying out tests on all of its affected lines but that no traces of contamination had been found in its products as of yet, the FSA said in a report on its website.
"The FSA has made us aware that a small number of people have fallen ill with a bacterial infection, and that one of their lines of investigation is watercress bought at Sainsbury's since August 1," a Sainsbury's spokesperson said.
"We have, as a precautionary measure, withdrawn six lines of pre-packed salad containing watercress from the supplier concerned."
The bacterium blamed for the illness, E. Coli 0157, can cause bloody diarrhoea, dehydration and, in the most severe cases, kidney failure.
"The FSA has made us aware that a small number of people have fallen ill with a bacterial infection, and that one of their lines of investigation is watercress bought at Sainsbury's since August 1," a Sainsbury's spokesperson said.
"We have, as a precautionary measure, withdrawn six lines of pre-packed salad containing watercress from the supplier concerned."
The bacterium blamed for the illness, E. Coli 0157, can cause bloody diarrhoea, dehydration and, in the most severe cases, kidney failure.