That doesn't sound right. We'd be perpetually bacteremic if that were the case.
Seems there's a paper on this (doi 10.1038/s41564-023-01350-w) that showed that 84% of people don't have bacteria in their blood. Authors hypothesized based on the detected bacteria that the remaining 16% were likely temporary colonizations and not permanent.
So for the most part, blood appears to be sterile with some possibility of temporary low level bacteremia