The hollow milk chocolate Easter bunny foil figures may contain a button battery which are a choking hazard and can cause burns if swallowed.
One contaminated product was found in Nottingham, UK last weekend.
Scale of problem
Just over 3,000 units have been sold nationwide and there has been no overseas distribution.
The chocolate bunnies were supplied by Wawi in Germany. We have contacted the company for comment.
Co-op said it had confidence in the manufacturing process because of the checks in place, which include metal detection units.
The supermarket said it was not speculating how the tampering occurred when asked if the foil packaging had an impact on the metal detector.
The National Crime Agency and police forces are helping with the criminal investigation and the Food Standards Agency has been notified. We have asked the FSA if other retailers could be affected.
A spokesperson for the Co-op said: “We are concerned about one incident of alleged product tampering involving our hollow milk chocolate Easter bunny foil figure, which has been found to contain a small battery inside.
“As a precaution, we have begun a UK-wide product recall and have withdrawn the product from sale.”
Xmas tampering incident
Customers with one of these products should not eat it but take it back to store for a full refund.
Button batteries are used to power hearing aids, watches, toys, flashing jewellery, singing greeting cards, remote control devices and other items.
It follows an incident at Christmas when two similar products, one found in Suffolk and one in Essex, were targeted and contaminated.
Co-op recalled 165,000 Hollow Milk Chocolate Santa's because of two reports of alleged tampering where the product was found to contain small batteries.
Wawi has eight production facilities in four continents and 500 employees worldwide.