John Russo said the manager apologized and blamed the mistake on a language issue. The manager suggested a worker with limited English saw the peanut notation and added it to the sandwich instead of keeping it out.
According to the lawsuit, a similar mistake happened a month later at the Wayland Panera. A grilled cheese arrived with peanut butter and caused a child to suffer an anaphylactic reaction.
Panera does post a warning that it cannot guarantee foods will be free of allergens because of shared equipment, but the Russo's attorney said this isn't a case of accidental cross contamination.