We present an Open Cultural Digital Content Infrastructure, a platform providing a coherent suite of loosely-coupled services that aim to promote quality in repositories and facilitate metadata and digital content reuse. The key functions of the infrastructure are the aggregation of metadata and digital files and the automatic validation of metadata records and digital material for compliance with quality specifications. The system that has recently moved to production, is currently being employed to ensure the quality standards of the output of more than 70 projects that support Greek cultural heritage organisations and are funded by the European Union structural funds. These projects are expected to produce more than 1.5 million digitized and born-digital items accompanied with detailed metadata. The validation is based on a set of quality and interoperability specifications that have been developed for the purpose. The infrastructure has been developed using an open source technology stack and tools and in particular reuses a number of components of the publicly available Europeana aggregator and portal software platform.