Alongside the UK, only four other EU member states are known to have met the turn of the year deadline on new pig welfare standards, leaving 13 European countries with many farms producing pigmeat that is illegal under EU law.
UK retailers have stated their intention not to stock imported pigmeat produced on these non-compliant European farms – but a recent NFU Scotland sweep of pork products at Tesco, Asda, Morrisons and Sainsbury's stores found some packs labelled as produce of Denmark, Holland, France and Germany.
The union has since returned to those stores and asked managers to start an audit trail to trace those products back to the source farm in their country of origin, to establish if they were among those that were abiding by the welfare legislation.
NFUS pigs committee chairman Phil Sleigh said: "Last week's furore around the production of beef burgers firmly underlines that all parts of the food chain are required to meet very high standards regarding the quality, traceability and labelling of fresh meat and processed products. Consumers expect no less.
"However, we are aware that there is a significant level of non-compliance to the sow stall ban in many other member states and pigs are still continuing to be produced in systems now outlawed across Europe.
"This is an opportunity for retailers to back up that reassurance with firm evidence by tracking imported products bought in individual stores all the way back to the farm of origin. If that were the case, it would send out a very positive message and we think a week is a reasonable time to complete that investigation," said Mr Sleigh.
"Given last week's revelations and questions on traceability, being able to provide an audit of the whole supply chain would show supermarkets to be delivering on their pledge and ensure that pig farmers – whether in Scotland or in Europe – are competing for shelf space in Scottish supermarkets on an equal footing."