To paraphrase Kermit, it ain't easy trying to be green. Those reusable bags that we substitute for paper or plastic can harbor bacteria and mold, according to a 2010 study by the School of Public Health at Loma Linda University.

To be green and safe, one company, has created a coated bag that is naturally antimicrobial, antibacterial and non-allergenic. Made from chitin, a substance found in discarded crustacean shells, the bags' coating has been called 100 percent safe by the Environmental Protection Agency.

But if you've got a trunk full of the original bags you'd still like to use, here are some precautions you can take.

Designate bags to use exclusively for meat and fish, washing them after every use. The reusable fabric bags can be washed the same way as sheets and towels. Reusable plastic bags can be soaked in a basin with soapy water and a quarter-cup of vinegar. Then hang to dry or put in the sun, which is a natural disinfectant, said Ami Voeltz of Do It Green! Minnesota. Hand or machine washing was found to reduce the bacteria in the bags by 99.9 percent, according to the study.

Despite the coating, Go Clean still recommends washing its bags, which will stay antimicrobial and antibacterial for six months and 20 washes.

The bags can be purchased for $5 from the website or, for a limited time, for $2.49 at Cub Foods stores in Chanhassen, Eden Prairie, Inver Grove Heights, Mankato, Minneapolis, Monticello, Rogers and Woodbury.