The potential health risks associated with the repeated use of reusable carry bags for groceries from bacterial cross contamination are usually ignored or dismissed.
- The emergence of reusable grocery bags is a relatively new phenomenon. The primary concern is the proper use of the bags, if they are to be reused multiple times to transport groceries. Conventional plastic shopping bags provide a sterile environment for food.
- Each year in Canada, there are 11 million cases of food-related illnesses due to improper handling of food, many of which are preventable.
- Two pieces of research have been conducted which provide directional evidence that reusable bags used to carry groceries can pick up or grow bacteria from a variety of sources, including the foods transported previously in the bag, from the external environment (when stored on the floor of a closet, under the sink, or in the rear of a car), and if used to carry other items between trips to the grocery store like sweaty gym clothing. This bacteria can be transferred from the surface of the bag to the food carried in the bag.
- There is now solid evidence of bacterial/viral transfer from a bag to humans based on a case published in USA Today involving a girls’ soccer team which was playing in Washington State. The team became infected with the Norovirus, which scientists later determined came from a reusable grocery bag. Tests revealed that the virus was on the sides of the bag below the polypropylene handle: http://www.lawyersandsettlements.com/lawsuit/reusable-shopping-bags-contaminated-with-deadly.html
- Two studies – one in the US and one in Canada, and both funded by the plastics industry – have been conducted and show that bacterial loading of the bags increases with repeated use and in the case of the American study, increases further, depending on where the bags are stored.
- Both studies conclude that the bags can be a breeding ground for bacteria and other coliforms.
- The U.S. Study was conducted by researchers at the School of Public Health. Loma Lindsay University and the Department of Soil, Water, and Environmental Science, University of Arizona. The US study findings are more extreme in terms of bacterial counts because they examined where the bags were stored. The Canadian study secured its bags by street intercepts and a majority of the bags tested were quite new.
- The Canadian study showed a particular sensitivity to perceptions of bias because of plastic industry funding so three independent testing laboratories were involved in this research study. Two labs executed the testing – Guelph Chemical Laboratories (GCL) and Bodycote Testing Group of Montreal—and a third provided oversight and evaluative commentary of the results: Toronto-based Sporometrics, the foremost experts in many aspects of fungal and environmental bacterial testing in Canada.
- Subject-matter expert, Dr. Richard Summerbell, Director of Research at Sporometrics, and the noted microbiologist who served as the Chief of Medical Mycology for Ontario Ministry of Health, Laboratory Services Branch from 1991-2000, evaluated the data.
- The Canadian study found that more than 30 percent of the used bags had unsafe levels of bacterial contamination, 40 percent had yeast or mold, and there was fecal bacteria embedded in the surface of some.
- In contrast, conventional plastic bags showed no evidence of bacteria, mold, yeast, or coliforms. According to the researchers, "The moist, dark, warm interior of a folded reusable bag that has acquired a small amount of water and a trace of food contamination is an ideal incubator for bacteria."
- Assessment of the Potential for Cross-Contamination of Food - Food Protection
- Assessment of the Potential for Cross-Contamination of Food - Food Legal
- Sporometrics » Reusable Grocery Bags
- Grocery Carry Bag Sanitation “A Microbiological Study of Reusable Bags and `First or Single-Use’ Plastic Bags"
- The Grocery Bag Controversy, Feb. 2012
- The Background file Toronto Staff RPT Exec