Were hygiene considerations part of the decision to charge for new grocery bags? I've seen customers put well-used (i.e., dirty) cloth bags on the conveyor belts where I put my food. These bags are also handled by the clerks who handle my food. —Getting Sick Soon

My first reaction upon receiving your letter, Sick, was to lift my head briefly, mutter, "Oh, Christ, what now?" and go back to sleep. (To be fair, this is my reaction to pretty much every letter I receive.)

However, in this case, your paranoia might not be entirely unjustified. Contamination from reusable grocery bags (RGBs) has certainly been an enduring theme in the nation's lifestyle media; I found articles on the subject going back at least a decade.

Why, just last month, a study published in Food Protection Trends magazine (subscribe now and don't miss a single thrilling issue!) found that fully half the reusable bags surveyed were tainted with coliform bacteria, with 8 percent testing positive for the dreaded E. coli.

Should we kill ourselves now, or just wait for the plague-drenched apocalypse? Well, before we revert to savagery, it might be worth examining this crisis with a slightly more jaundiced eye.

For starters, there's E. coli and there's E. coli. Although some strains do cause diseases like shigellosis, most are benign.

They're also everywhere. For example, while you've been freaking out over the 8 percent of RGBs that carry E. coli, approximately half of all grocery carts have been testing positive for it for years. Don't even get me started on cellphones, doorknobs or your underwear.

Also, you know that study I mentioned? It was funded in part by the American Chemistry Council, formerly known as the Chemical Manufacturers' Association, a trade group that represents a lot of the plastic bag industry.

This is not to say RGBs can't get funky, but what doesn't? (One of the study's experiments put meat juices on the bags and left them in a 92-degree car trunk for two hours, which strikes me as a pretty heavy thumb on the scale.)

In any case, the whole problem is eliminated if you just launder your RGBs once a week or so. Feel free to try the same trick on your underwear.