A new study finds that reusable grocery bags could carry dangerous levels of bacteria, which can be harmful to humans.

Well, duuhh.

This is apparently a controversial finding.

Jabs are currently going back and forth between University of Arizona researchers (whose study was partly funded by the American Chemistry Council) and the National Resources Defense Council (NRDC), an environmental advocacy group which objects to the study’s validity.

The NRDC says it's irresponsible to claim that reusable bags present a serious threat to public health because bacteria are everywhere.

Meanwhile, common sense advocates are reminding us that we wouldn’t wear the same clothes every day without washing them, so apply the same logic to your cloth grocery bags, for goodness sakes.

Amazingly, a full 97 percent of those interviewed for the study never washed or bleached their reusable bags; even thorough washing kills nearly all bacteria that accumulate in the bags.

The UA study tested 84 bags collected from shoppers in Los Angeles, San Francisco and Tucson. Fifty percent of the bags were contaminated with harmful pathogens -- 12% of which was E.coli. That’s the stuff found in fecal matter, or poo. E. coli can cause a whole host of nasty -- and potentially deadly -- diseases. It’s definitely something you want to avoid eating.

According to the study, cross-contamination within reusable bags is the culprit for most of the bacterial findings. Cross-contamination happens when uncooked items like meat, poultry and eggs leak onto a fabric bag. If the bag isn’t washed after such a leak, the bacteria left by the raw food can contaminate other food stored in the bag on your next grocery trip.

While these findings could potentially scare some consumers, I don’t think anyone would seriously advocate giving up on reusable bags. But you do have to take responsibility for your bags and maintain them properly.

Wash bags regularly to cut down on bacterial contamination.
Let me say this again for those of you who are skimming this article: Washing kills nearly all bacteria that accumulate in the bags. This is a no-brainer, people.

Don’t mix it up where reusable bags are concerned.
Designate bags for certain uses. Example: Use one bag specifically for meat, one for produce, one for other household items like detergent and cleaning solutions, and one specifically for toting library books and dry cleaning.

Don’t store bags in the trunk.
I know, I know, this might cut down on convenience, but remember that a hot trunk, filled with soccer shoes and wet beach towels makes an excellent nursery for bacteria. Plus, the higher temperature in your trunk can actually speed the reproduction of bacteria on fresh food. Also, what gets on your bag gets on your hands, and then on your groceries. Do you really want to bring the mud from the baseball field into your kitchen? Think about it.

The UA study is a little alarming, especially when regular hand and clothes washing has been around since the Romans started the tradition about 3000 years ago. But, it always takes some people a little longer to catch up. So remember to wash your reusable bags just like you would any other thing you use frequently.

By recognizing the potential for cross-contamination, and taking steps to prevent it, you can protect yourself, your family and the environment. And that’s something you can feel good about.