Fresh Express has announced the recall of Leafy Green Romaine Salad due to a positive test result for listeria contanination.

The company said that the positive result was found on a single pack from “many samples” collected by the USDA.

The recall relates to salad with a use by date of 16 September and is being made in the “unlikely event” that consumers have out of date salad in their refrigerators, the company said.