Role of Whole Genome Sequencing in Assessing Resident and Transient Listeria monocytogenes in a Produce Packinghouse.

Whole genome sequencing (WGS) is a powerful tool that may be used to assist in identifying Listeria contamination sources and movement within environments, and to assess persistence. This study investigated sites in a produce packinghouse where Listeria had been historically isolated; and aimed to characterize dispersal patterns and identify cases of transient and resident Listeria. Environmental swab samples (n = 402) were collected from 67 sites at two time-points on three separate visits. Each sample was tested for Listeria, and Listeria isolates were characterized by partial sigB sequencing to determine species and allelic type (AT). Representative isolates from the three most common L. monocytogenes ATs (n = 79) were further characterized by WGS. Of the 144 Listeria species positive samples (35.8%), L. monocytogenes was the most prevalent species. L. monocytogenes was often coisolated with another species of Listeria. WGS identified cases of sporadic and continued reintroduction of L. monocytogenes from the cold storages into the packinghouse and demonstrated cases of L. monocytogenes persistence over 2 years in cold storages, drains, and on a forklift. Nine distinct clusters were found in this study. Two clusters showed evidence of persistence. Isolates in these two clusters (N = 11, with one historical isolate) were obtained predominantly and over multiple samplings from cold storages, with sporadic movement to sites in the packing area, suggesting residence in cold storages with opportunistic dispersal within the packinghouse. The other seven clusters demonstrated evidence of transient Listeria, as isolation was sporadic over time and space during the packing season. Our data provide important insights into likely L. monocytogenes harborage points and transfer in a packinghouse, which is key to root cause analysis. While results support Listeria spp. as a suitable indicator organism for environmental monitoring surveys, findings were unable to establish a specific species as an index organism for L. monocytogenes. Findings also suggest long-term persistence with substantial SNP diversification, which may assist in identifying potential contamination sources and implementing control measures.

Pilot projects for improving product tracing along the food supply system.

In September 2011, the U.S. Food and Drug Administration (FDA) asked the Institute of Food Technologists (IFT) to execute product tracing pilot projects as described in Section 204 of the FDA Food Safety Modernization Act (FSMA). IFT collaborated with representatives from more than 100 organizations-including the U.S. Dept. of Agriculture, state departments of agriculture and public health, industry, and consumer groups, as well as not-for-profit organizations-to implement the pilots. The objectives of the pilot projects were 1) to identify and gather information on methods to improve product tracing of foods in the supply chain and 2) to explore and evaluate methods to rapidly and effectively identify the recipient of food to prevent or mitigate a foodborne illness outbreak and to address credible threats of serious adverse health consequences or death to humans or animals as a result of such food being adulterated or misbranded. IFT conducted evaluations to determine the impact of currently available technologies, types of data and formats, and the data acquisition process, as well as the use of technology on the ability to follow product movement through the supply chain. Results from the pilots found inconsistencies in the terminology, numbering systems, formatting, legibility, and occasionally the language that sometimes required IFT to contact the submitting firm to gain clarity, thus increasing the time required to capture data before any meaningful analysis could begin. However, the pilot participants appeared to have many of the tools and processes in place which are required to allow the capture and communication of critical track and trace information (such as, key data elements) at critical points of product transfer and transformation (such as, critical tracking events). IFT determined that costs associated with implementing a product tracing system can vary widely as determined by numerous factors: the size of the firm/facility, the method of product tracing already in use (manual or electronic), and the range of each firm's capabilities to implement or improve its product tracing system, to name a few. IFT found that there are several areas (such as uniformity and standardization, improved recordkeeping, enhanced planning and preparedness, better coordination and communication, and the use of technology) in which industry improvements and enhancements to FDA's processes would enable tracebacks and traceforwards to occur more rapidly. IFT developed 10 recommendations for FDA to consider for improving the state of system-wide food product tracing. The recommendations outlined in the report will enable FDA to conduct more rapid and effective investigations during foodborne illness outbreaks and other product tracing investigations, thus significantly enhancing protection of public health.

Making traceability work across the entire food supply chain.

The Institute of Food Technologists held Traceability Research Summits on July 14, August 22, and November 1, 2011, to address how to meet the growing requirement for agriculture and food traceability. Each meeting had a group of about 50 individuals who came from food companies, trade associations, local, state, and federal governments, 3rd-party traceability solution providers, not-for-profit corporations, consultants, and consumer groups. They discussed and deliberated the objectives of traceability and the means to develop product tracing in the food system. A total of 70 people participated in the 3 summits. These individuals were invited to participate in a small workgroup responsible for considering the details related to product tracing and presenting draft concepts to the larger group on November 1, 2011, in Chicago. During this meeting, the larger assembly further refined the concepts and came to an agreement on the basic principles and overall design of the desired approach to traceability.

Proceedings of the July 2011 Traceability Research Summit.

At a discussion-based forum of 50 leaders in the area of food product tracing, participants recognized the need for the development of a common vision for a simple, low cost and implementable traceability approach. A key theme that emerged during the day's discussions revolved around not reinventing the wheel: there are many efforts underway, including numerous pilots, and these efforts should be collaborative. The group sought more information on current initiatives and felt that learning from the experiences of others could help form a realistic vision for the future. Although any forthcoming actions from the US FDA are unknown, industry fully expects that improvements in product tracing will be necessary, and expects that industry itself (through the "demand" side) will enact requirements that may surpass regulatory mandates. A chief concern is uniform adoption, which will require outreach to and support from the global community as well as small firms that may lack the resources and education to keep up. Ultimately, an approach that is global, economical, scalable, and inclusive of firms of all sizes who handles all types of food products, will have the greatest likelihood of success. While the ability to rapidly link products across the supply chain serves as an ideal goal, there are still substantial concerns to be addressed, particularly regarding confidentiality of data, and who will have access to what information under what circumstances, which was woven into virtually every discussion topic. Who will spearhead the development of the visions is a question, but there was general agreement that a joint partnership which includes all stakeholders is a necessity.

Proceedings of the August 2011 Traceability Research Summit.

IFT's Traceability Improvement Initiative aims to advance work in the area of food product tracing through several means including hosted events where thought leaders exchange knowledge and ideas. In August 2011, the Initiative, in collaboration with GS1 US, convened a group of 50 product tracing stakeholders, as a follow-on to a successful event the month prior. Representatives conducting pilots or implementation studies in produce, seafood, dairy, and other industries discussed the objectives, challenges and learnings. Some of the learnings from on-going initiatives included the sense that better information management provides a return of investment; data often exist but may not necessarily be appropriately linked through the supply chain; and enhanced product tracing enables better accountability and quality control. Challenges identified in enabling traceability throughout the supply chain were the distribution complexity; the need for training, communication, and collaboration; improving the reliability, quality and security of data captured, stored and shared as well as the importance of standards in data and interoperability of technology. Several approaches to overcoming these challenges were discussed. The first approach incrementally improves upon the current "one up/one down" system by requiring electronic records and tracking internal as well as external critical tracking events. The benefits of this approach are its similarity to existing regulatory requirements and low cost of implementation; resulting in a higher probability of adoption. The major disadvantage to this process is the longer response time required during a trace (back or forward). The second approach is similar to a "pedigree" approach where historical information about the food travels with it through the value chain. A major advantage of this approach is the quickest response time during a trace. Some of the disadvantages of this approach are potential for misuse of data, the volume of data required to be maintained at value chain end points, and data privacy concerns. The third approach requires individual nodes within the value chain to maintain electronic records for its own data and make them available for querying during a traceback for outbreak investigation. The major advantage of this approach is the protection of confidential information and the potential for quicker access during a trace. However, the primary disadvantage of this approach is the need for greater computational power and a more complex mechanism to linking the value chain through the data. As next steps, a subgroup will work on clarifying the approach to meeting the goals of traceability, better defining critical tracking events, and articulating the strategy and return on investment from a regulatory and industry perspective. This will result in improved alignment of on-going traceability pilots and initiatives as well as a more actionable guidance document for public review.