Survival of Salmonella on the Surface of Plastic Grocery Bags through Leakage from Raw Chicken Packages

Introduction: Consumers often keep the grocery bags from shopping trips to reuse for other purposes. There are food safety concerns in reusing the bags that were used in wrapping raw poultry products. The leakages from the packages can often carry foodborne pathogens such as Salmonella. However, there is no scientific data to assess such risk. It is not clear how long Salmonella from the leakages can survive on the surface of plastic grocery bags.

Purpose: The objective of this study was to evaluate the attachment and continued existence of Salmonella from leakages onto plastic grocery bags.

Methods: Salmonella cells were mixed with the meat juices collected from chicken packages. The mixtures were applied to the surfaces of pieces of plastic bags cut into 2 in. x 2 in. squares either uncovered or covered with another piece of plastic on top. Salmonella on the surfaces were enumerated with both selective (XLT-4) and non-selective (APC) agar methods for two weeks and the experiments were repeated five times.

Results: In the covered condition, it took 4.2 and 8.8 days to reduce Salmonella counts to one-thousandth of the original numbers when enumerated with XLT-4 and APC, respectively. In the uncovered condition, it took 12.0 and 22.4 days to reach the same levels of Salmonella with XLT-4 and APC, respectively. The longer surviving days observed in the uncovered condition implied a protective mechanism involving the dryness, oxygen exposure, and protein film. The longer surviving days observed with the non-selective method indicated better recovery rates of Salmonella than that with the selective method. The harshness of selective agents may suppress the recovery of Salmonella from the surfaces.

Significance: Salmonella can persist on the plastic surface for long period of time. It is important not to reuse the bags that had been used in wrapping raw poultry packages to prevent cross contamination.