Switching exclusively to single-use packing units for shipping to processors and other market receivers is clearly one option to essentially eliminate concerns for cleanliness of FCS containers with intimate product contact points. In a recently completed study of the microbiological status of single-use corrugated packing containers, with the participation of UCD in the study design, representing six different manufacturers, third-party findings supported the expectation that the FCS area was “clean” and well below presumptive comparable standards derived from the Guelph study.
Naturally, protection from contamination during staging and use in field harvest or during on-site storage at a packing or fresh-cut processing facility is an essential and long-standing expectation in all prerequisite produce safety programs. Single-use liners also greatly reduce concern with diverse multiple-use shipping containers; however, this practice is not always applicable with some produce handling systems. For example, these liners will interfere with prompt cooling or drying of product and may be associated with a greater level and persistence of condensation on product leading to decay and food safety concerns.
While adopting single-use only packaging policies among shippers and receivers would alleviate concerns for all forms of multiple-use packaging, this is not a realistic approach. Until such time as there is abundant evidence that RPC units arrive from a depot in an acceptable condition as a sanitized and dry FCS, ready to receive fresh produce, we recommend that growers and shippers adopt a consistent inspection protocol for each pallet received. We strongly suggest that inspection be combined with replicated adenosine triphosphate-bioluminescence swabs to support visual inspection (Table 1) and, over time, to design and implement a random 10-RPC swab protocol for total Enterobacteriaceae and total thermotolerant coliforms. This data should be provided openly to RPC providers and receiving customers in order that overall system improvement may be broadly supported and expedited. To support this standardized protocol, we are developing additional validation data to strengthen science-based guidance values for cleanliness of multiple-use harvest and packaging containers.
Dr. Suslow is produce safety specialist at the department of plant sciences at the University of California, Davis. Copies of his study are available on request. Reach him at firstname.lastname@example.org.