How to understand "often enough" in this sentence
In this sentence:In so far as any inquiry is a secret one, it naturally limits all those engaged in carrying it out from effective contact with their fellow scientists either in other countries or in universities, or even, often enough, in other departments of the same firm.
What's the meaning of "often enough" in this sentence? Why does the sentence add "often enough" and what's the function of it in the sentence?