Investigators in Italy have uncovered large-scale fraud in the balsamic vinegar sector, with fraudsters suspected of using lower-grade grapes to make products they then intended to pass off as authentic balsamic.

Balsamic vinegar of Modena is protected under the EU’s PGI protected foods scheme, which stipulates it be made with grapes of the Lambrusco, Sangiovese, Trebbiano, Albana, Ancellotta, Fortana or Montuni varieties and produced within the Italian provinces of Modena and Reggio Emilia.

However, a major Italian fraud investigation – dubbed Operation Global Wine – has uncovered “the fraudulent use of table grapes” to make products that were subsequently described as balsamic. Investigators seized €15m (£12.9m) worth of grape must and wine products, as well as numerous documents showing how provenance and authenticity credentials were falsified.

There is no suggestion that food safety was compromised, and the Italian ministry of agricultural food and forestry policies said the investigation showed how vigorously Italy protected the reputation and quality of its food products.