As someone who regularly uses the reusable grocery bags this study was not exactly encouraging.
It seems they tested a bunch of bags and many of them were contaminated with all kinds of nasty bacteria up to and including E Coli.
To be fair the study was sponsored by the ‘American Chemistry Council’ which presumably has an interest in continuing to sell plastic bags.
But in theory we have to run them through the washer, which may cancel out some of the environmental benefits, though I mostly used them for convenience anyway.
Still, another example of unintended consequences.