The first question is whether the products you make are plastic and for direct contact with food or other high risk product. If so, then as Simon said, you need to provide a Declaration of Compliance if you sell within the EU under EU Law.
The BRC takes this Declaration requirement a bit further. It requires that it is provided for all packaging types that come into direct contact - paper, metal, glass etc. even though it is not currently a fully implemented legal requirement.
It also requires that even if your products are not in direct contact, but the contact layer is not an absolute barrier, then your products are considered high risk and will also require a Declaration. There are other threads about the definition of an absolute barrier.
One of the statements that this Declaration must contain is whether any of the raw materials contain any post-consumer recycled materials. It does not state that they must not contain any of these materials.
The only way to be able to make this statement is to understand your suppliers processes and in reality obtain full warranties from your suppliers.
It is up to you then to evaluate the information. If there are post consumer recycled materials, you need to assess what risks there may be to consumers.
As an example, there may be problems with the use of recycled printed paper with resulting contamination of food by mineral oils.