One green pet cause du jour is the banning or taxing of disposable plastic bags at supermarkets and other grocery stores. These measures, which are designed to encourage shoppers to use their own reusable tote bags, have been spreading widely in recent years, and have already gone into effect in cities like San Francisco, Seattle, and Washington, D.C.
Reusable bags were collected at random from consumers as they entered grocery stores in California and Arizona. In interviews, it was found that reusable bags are seldom if ever washed and often used for multiple purposes. Large numbers of bacteria were found in almost all bags and coliform bacteria in half. Escherichia coli were identified in 8% of the bags, as well as a wide range of enteric bacteria, including several opportunistic pathogens. When meat juices were added to bags and stored in the trunks of cars for two hours, the number of bacteria increased 10-fold, indicating the potential for bacterial growth in the bags.