Barossa Police were notified yesterday that a customer had found a nail in a strawberry punnet.
The punnet had been purchased on 15 August at Gawler.
The packaging and nail have been forensically examined and police are awaiting the results.
The remaining stock was examined and no other items were found and police are not aware of any other such reports.
Investigations are ongoing and police have not ruled out accidental contamination.
Police would stress that responsible reporting of this incident is vital to avoid generating unnecessary public fear or detriment to the industry.
SA Health have been advised.