Minimizing Microbiological Risks in Multiple-Use Containers

Image Credit: T. Suslow.
Internal system multiple-use plastic containers may be a cyclical conduit for foodborne pathogen transport, such as Listeria monocytogenes, between field or orchard and packing/processing facilities.

Dedicated food safety professionals do more than manage their company’s risk by becoming skilled at passing audits. Nowhere is this more true or needed than in the fresh produce industry. Whether raw agricultural commodities (RAC), minimally-processed fruits, vegetables, or other edible horticultural crops (hereafter collectively called fresh produce), assessing hazards and defining both risk potential and risk exposure have become an evolving and expanding systems-based focus in food safety planning. In anticipation of the final rules fulfilling provisions of the Food Safety Modernization Act, produce-buying customer specifications, and global standards for prerequisite programs, a deeper analysis of diverse system inputs as sources of contamination and cross-contamination is being applied across the supply and marketing chain.

Without question, this increasing recognition that the “devil is in the details” may be attributed to the numerous recalls of RAC and minimally processed produce in recent years. These recalls, often encompassing multiple lots, several weeks of production, or entire seasonal shipments, are largely triggered by detection of foodborne pathogens in random or category-targeted testing programs. Distinct from the goal of preventing the unknowing shipment of adulterated produce that may result in consumer illness or outbreak, minimizing the potential of positive outcomes from company internal or external testing of packed containers or finished product for pathogens has prompted the industry to seek risk reduction measures in under-evaluated system components. In 2014 alone, we can identify more than 18 non-outbreak recalls of diverse fresh produce and tree nuts as the result of the identification of pathogens, including Shiga toxin-producing E. coli, various Salmonella serovars, and Listeria monocytogenes, on product introduced to interstate commerce (U.S. FDA). The full economic impact and ripple effect of these incidents, from suppliers to receivers in food service and retail outlets, can be substantial as evidenced by the large recall of California stone fruit during the summer of 2014. Other recalls and actual outbreak incidents just before and, especially, closely following the various Listeria-associated recalls have activated a broad call to action within the industry not experienced since the 2006 E.coli O157:H7 outbreak on spinach and among the cantaloupe category during and following the 2011 L. monocytogenes outbreak originating from a Colorado shipper.

Expanding View of Contact Surfaces

Driven by this increasing concern applied to the expanding view of system control points and presumptive contamination transfer surfaces, practices associated with food safety assurances applied to multiple-use containers are being scrutinized. In the fresh produce supply chain, multiple-use containers encompass many different types of containers, fabrication materials, and system uses. Multiple-use containers may be divided into two broad categories based on ownership and control of the containers. Simplistically, these include exclusively internal (closed-loop) systems or multiple-user pool system containers with limited traceability and knowledge of prior use-history, potentially among many international shippers and receivers. An additional category of concern is the widespread practice of single-use produce packaging and shipment containers that are handled as reusable containers and find their way into both interstate commerce and local-grown produce, which is direct-marketed. This topic will be covered very briefly later in this article.

Each of these forms of multiple-use containers fit appropriately into any system analysis of food contact surface (FCS) cleanliness and sanitation programs. The uncertain linkage and limited documentation of the potential for diverse primary and secondary use of these containers to serve as vectors of contamination, within and among lots, does not negate the necessity to include their consideration in a comprehensive preventive control program. Whether an internal, closed-loop system or a pool-system of reusable units, these containers intended for multiple-cycles of use with fresh produce may contact product directly during various harvest practices.