Is a bacterial nuclease contamination possible during protein purification?

I am currently using a recombinant protein which shows metal-dependent DNase activity. Is it possible to pinpoint the source of the DNase activity after protein purification? More specifically, can I ensure that the DNase activity is not because of nuclease contamination from the E.coli that might have persisted and passed with the protein of interest during purification?

Experiment: Protein isolation Bacteria - Escherichia coli