Dry Bulb Onion Storage in Sterilized Plastic Crates Compared to Storage in Old Wooden Boxes

As part of the Food Safety Modernization Act (FSMA), the United States Food and Drug Administration, (FDA) has mandated that produce storage containers be sanitary for their intended purpose. This mandate could potentially lead to efforts to replace wooden storage bins with plastic totes under the assumption that plastic containers would be more sanitary for onion storage. Replicated studies were conducted in 2015 to compare the roles of wooden and plastic storage containers on contamination of onion bulbs with Escherichia coli. Onions from five replicated furrow-irrigated plots using water containing 62.4 to greater than 20,957 MPN (most probable number) E. coli /100 ml were harvested into 10 old wooden boxes and 10 sterilized plastic crates. Onions from five replicated drip-irrigated plots using water with 0 MPN E. coli /100 ml were harvested into an additional 10 old wooden boxes and 10 sterilized plastic crates. Onions were stored for six weeks and then prepared for shipment through removal of loose skin, roots and soil. None of these packed out onions had detectable E. coli on the bulb exteriors or interiors, regardless of storage container type or irrigation water source. Plastic containers did not provide added food safety value compared with wooden bins for the storage of dry bulb onions.