A PUBLIC-HEALTH NIGHTMARE: The Disgusting Consequences of Plastic-Bag Bans. “In a 2011 study, four researchers examined reusable bags in California and Arizona and found that 51 percent of them contained coliform bacteria. The problem appears to be the habits of the reusers. Seventy-five percent said they keep meat and vegetables in the same bag. When bags were stored in hot car trunks for two hours, the bacteria grew tenfold. That study also found, happily, that washing the bags eliminated 99.9 percent of the bacteria. It undercut even that good news, though, by finding that 97 percent of people reported that they never wash their bags.”