Grocery stores across seven US states have pulled tuna salad items off their shelves after fears of listeria contamination. The recall, announced by the US food and drug administration (FDA) on Monday, was linked to products supplied by Reser’s Fine Foods. The contamination was traced to breadcrumbs used in the tuna salads. No cases of illness have been reported so far. The affected items include sandwiches, croissants, snack packs and salad trays sold in Jewel-Osco outlets in Illinois, Indiana and Iowa, and in Albertsons, Randalls and Tom Thumb stores in Arkansas, Louisiana, Oklahoma and Texas. All the products have specific sell-by dates between 16 and 19 July. Customers have been advised to throw away or return recalled items for a full refund.What is ListeriaListeria is a bacteria that can cause severe illness, especially in pregnant people, the elderly, children and those with low immunity. The infection may lead to fever, nausea, diarrhoea or, in serious cases, miscarriage or stillbirth.The FDA has also asked people to clean all surfaces that may have come into contact with the products, warning that listeria can survive in cold storage like refrigerators.