SOP For traceability of control samples is described in this post which you can follow in the section of the Quality Assurance Department.

This procedure is established to provide process for traceability & retention of control samples.
This procedure is applicable for identification & traceability of control samples.
QA Inspector & QA Assistance are responsible for the implementation of this SOP. 
Sampling of finished products should be done during online packing. 
Finished products (control samples) should be collected at different-intervals i.e. start, middle and end of the packing operation.
After completion of the batch, bring samples to QAD.
Enter the Product Name, Batch No. & quantity sampled in QA Retained Sample Record.
After this, place the samples in a shipper. When the shipper is full, sealed the shipper.
Prepare  the identification label indicating Product Name, Batch No and number of sampled units enclosed in the shipper
Now paste this label on the front side of the shipper. 
Transfer the shipper to control sample retention room and place at respective space. 
In control sample retention room shippers are arranged alphabetically according to month and year wise.
Control samples should be stored in control sample retention room as per legal and regulatory requirements. 
Control samples should be under controlled conditions of temperature and humidity.