A new study has confirmed what proponents of single-use corrugated containers have said for years — the corrugating process uses temperatures high enough to kill germs, ensuring that the boxes don’t introduce pathogens into the food supply chain. Maryann Sanders, senior regulatory specialist and microbiologist at Haley & Aldrich Inc., directed the NSF International study, which was sponsored by the Corrugated Packaging Alliance. “The main point of the study was to make sure our house is in order. We had the hypothesis but it hadn’t been proven until this research was done,” Sanders said when the study results were released earlier this month. Sanders has been working with the corrugated industry for 10 years. As a microbiologist she knew that pathogens couldn’t survive the high temperatures — 180 to 200 degrees Fahrenheit — used to shape and bond the layers of paper into the rigid corrugated material known to laymen as cardboard. However, no one had specifically documented that fact. Something else no one has documented is a foodborne illness caused by pathogens on reusable plastic containers (RPCs), which some retailers have begun requiring for fresh produce shipments.

“If I were a retailer or a supplier, I wouldn’t want to be the first one to have a documented problem,” Sanders said, adding that research sponsored by the RPC industry has shown high levels of pathogens on the reusable containers. That research showed RPCs on the same pallet ranged from zero microbial organisms to 10 million organisms. Sanders said she suspects the wildly different levels are a reflection of inadequate or improper sanitizing between uses. Trevor Suslow, an extension specialist and food safety researcher at the University of California-Davis, consulted on both the RPC study and the corrugated study. He said fresh produce growers and shippers frequently ask him whether they should use single-use corrugated containers or RPCs. The answer is not easily determined. The pressure of retailer requirements cannot be ignored, Suslow said. When a customer says they want to receive products in RPCs, some growers cannot afford to say no. Suslow said the basic concept of multi-use containers sets them up to become contaminated, especially if they are used for commodities that are packed in the field, which includes many fresh produce commodities. “If you are required to use RPCs, be sure to inspect them upon receipt,” Suslow said. “If you see a problem, document it. You can also use quick swab tests to check the general levels of (microbial growth).” Such precautions are unnecessary with single-use corrugated containers, Sanders said. (To sign up for a free subscription to Food Safety News, click here.)