The main aspect of database protection is to prove the ownership of data that describes who is the originator of data. It is of particular importance in the case of electronic data, as data sets are often modified and copied without proper citation or acknowledgement of originating data set. We present a novel method for watermarking relational databases for identification and proof of ownership based on the secure embedding of blind and multi-bit watermarks using Bacterial Foraging Algorithm (BFA). Feasibility of BFA implementation is shown in the framed watermarking databases application. Identification of owner is cryptographically made secure and used as an embedded watermark. An improved hash partitioning approach is used that is independent of primary key of the database to secure ordering of the tuples. Strength of BFA is explored to make the technique robust, secure and imperceptible. BFA is implemented to give nearly global optimal values bounded by data usability constraints and thus makes database fragile to any attack. The parameters of BFA are tuned to reduce the execution time. BFA is experimentally proved to be better solution than Genetic Algorithm (GA). The technique proposed is experimentally proved to be resilient against malicious attacks.