LOS ANGELES (CBS) — A voluntary recall has been issued for 2,300 cases of chopped romaine lettuce.

One bag of lettuce with a use-by date of Sept. 29, which was grown on True Leaf Farms in Salinas, has tested positive for listeria.

The company says the lettuce was bagged at its San Juan Bautista facility.

There have been no reported illnesses, but listeria can be deadly, and is especially dangerous to those with compromised immune systems.

Officials urge those who purchased the potentially tainted product, which carries a bag and box code of B256-46438-8, to throw it out.