Listeria - Why is it Not Going Away ? - Part I
Craig Kahlke

For Part I - please see FN volume 16, Issue 14 (June 22, 2016) or click here: https://lof.cce.cornell.edu/submission.php?id=427&crumb=food_safety|food_safety

To summarize part I, two deadly Listeria monocytogenes (Lm) outbreaks were covered, that hospitalized a combined 182 people, with 40 deaths. For the first time, a foodborne illness was associated with fresh apples in the Bidart Brothers outbreak. Better technology has allowed increased detection of Listeria spp., Escherichia coli, Salmonella spp., and other pathogens that cause foodborne illness in fresh produce. The number of recalls (positive results of the previous pathogens) has increased, but the number of outbreaks and individual illnesses has not increased. Sanitation to reduce risk of these pathogens in the field is difficult. There are some practices at the farm level to reduce the likelihood of Lm; however, the focus needs to be in the packinghouse. There is a great need for equipment that can be easily cleaned, sanitized, and allowed to dry at the end of each day. What is available in the marketplace today is still lacking, but newer packing lines and packing equipment available today are beginning to utilize principles of sanitary design, in which the equipment is constructed with materials that are more resistant to microbial growth and designed in a manner that facilitates easy cleaning and sanitizing.
Center for Produce Safety (CPS) Annual Symposium

There is a lot of research happening in the US to address the big questions regarding Lm and other pathogens that are causing foodborne illness in fresh produce. Since my article in mid-June, the Center for Produce Safety (CPS) had its annual symposium, summarizing funded applied research projects in all aspects of foodborne contamination on fresh produce. The two-day conference was kicked off with a large panel session: A Case Study - Part I: Lm Outbreak and Caramel Apples; Part II: Lm, Caramel Apples and What We Learned. The panelists dissected the outbreak from a scientific and public health perspective. Panelists included representatives of the CA Dept. of Public Health, Centers for Disease Control & Prevention, several university scientists, USDA, and the Northwest Hort Council. Whole genome sequencing (WGS) was introduced as a tool in the epidemiological traceback, and found that Listeria was still present, even months later when the environment in the packinghouse was dry and completely free of water. This upended some of the conventional thinking about Listeria and its ability to survive in dry environments.

Research was presented that demonstrated the potential for Lm growth in caramelized apples. Observations from the production facility investigation were shared. There were very large failures in communication between industry and regulatory agencies and between the U.S. and export partners and the role that social media played were examined. While Bidart Brothers were a small packinghouse that did not export apples - word got out from the outbreak and exports from WA to Asia were halted, needlessly costing the industry millions.

Most importantly, the actions of the apple industry in the Pacific Northwest subsequent to the outbreak were highlighted. The industry moved quickly to provide education and training to apple producers about Lm and focused on equipment and facility sanitation. It is important to evaluate equipment and sanitation practices to insure that cleaning and sanitation is effective, and Lm is not permitted to become resident. It is also important to understand how produce is being used in the manufacturing of other products (such as caramel apples, apples slices etc.) and what impact that might have on its safety. Lastly, being prepared for a food safety event is imperative. Having proper lines of communication within your company, with other groups in your commodity, with the regulatory agencies and even at a country-to-country level are keys to insuring negative consequences of a potential outbreak are minimized. This has a critical and direct impact concerning the number of people sickened and the ability to keep false information from damaging a large proportion of the industry.

While GAPs training has been widely accepted among fresh apple producers, the focus has now shifted to Lm control, training, cleaning and sanitation in packinghouses as well as the use of guidance documents for tree fruit operations and the set up of effective environmental monitoring programs. In addition, industry has been working with academia to determine preventive measures and potential food safety risks. The University of Wisconsin, UC Davis, Cornell University and the Washington Tree Fruit Research Commission (WTFRC) shared the results of research conducted in apple operations to understand how the outbreak occurred, how a facility can be vulnerable to contamination, and the need to implement practices that address the minimization of situations where Listeria can be widely distributed in an operation.

Ines Hanrahan in NY
The NY commercial apple industry was very fortunate to have Dr. Ines Hanrahan of the WTFRC speak to us at the Empire Producers Expo in Syracuse this past January. Ines gave two similar food safety presentations to two groups at the Expo- a farm food safety plan writing group, and at a tree fruit session. A pdf of her slide sets (combined from her 2 talks) are found on the Expo proceedings website here: http://www.hort.cornell.edu/expo/proceedings/2017/TreeFruitHort.Orchard%20management%20to%20restrict%20foodborn%20pathogen.pdf To quickly summarize highlights of the restricting foodborne pathogens portion, Ines explained how the Washington tree fruit industry responded quickly with out-of-cycle funding to work with a diverse committee to investigate the causes of Listeria contamination on commercial storage and packing facilities of apples and how to best implement a prevention plan. Her talk covered three main topics: the approach to food safety before an outbreak, an approach after an outbreak, and key learnings.

Food Safety Before an Outbreak
The Northwest Hort Council (NHC) formed a food safety committee in 2007. In addition, the Center for Produce Safety (CPS) allocated research dollars because a partnership was formed with WTFRC. The Washington State Tree Fruit Association provided GAPs trainings, and the WTFRC worked with all of the groups to coordinate efforts. A thorough review was performed to make sure all 3rd-party private food safety audits were being met at the orchard and packinghouse level. Research was conducted to look at the potential for bacterial contamination on fruit with agricultural water put on close to harvest as irrigation or in crop protectant sprays. In addition, research was performed looking at reducing potential bacterial growth and cross-contamination in the postharvest environment. The goal was to develop Standard Operating Procedures (SOPs) for packinghouses, including the lines, dumptanks, spray bars, and drying areas, and bin sanitation. The key message here continues to be the need to be proactive.

Food Safety After an Outbreak
The NHC Food Safety Committee designated a sub-committee for Listeria. They identified priorities and had focuses on Lm at their previous two annual meetings. Industry organizations worked together towards a common goal - everyone loses if there is an outbreak. Additional funding was provided by the WTFRC to address these issues. The Listeria sub-committee prioritized the identification of training needs, research needs, and the production of guidance documents.
Combining the needs for guidance documents, training, and the incorporation of current research produced cleaning and sanitation workshops for the WA tree fruit industry. The workshops are called "Putting Principles into Practice, A Hands-On Workshop for Sanitation Supervisors and Packing Line Managers". For the first time ever, doors were opened to packinghouses and competitors were invited. The workshops begin with an overview of Listeria risk and the importance of cleaning and sanitation, and then continued with hands-on demonstrations of effective cleaning and sanitation practices. The hands-on includes identifying areas of risk within your facility, how to handle challenging areas, including drains and the proper use of cleaning equipment and products. The workshop concludes with strategies for successful implementation. An advanced version of these workshops was later organized to train tree fruit industry food safety specialists on environmental monitoring techniques to verify the efficacy of cleaning and sanitation practices in the packinghouse. This workshop also incorporated classroom and hands-on education. Topics covered during the classroom presentations included the importance of environmental monitoring (EM), current EM techniques used, facility mapping and hygienic zoning.

Key impacts of all workshops to date include, but are not limited to: increased communication between competing organizations (facilities opened doors to direct competitors to share their processes and expertise), active collaboration between industry members (coffee/discussion groups were formed to exchange ideas), expanded research programs, strengthened industry cooperation with food safety research, involvement of the tree fruit industry in food safety meetings and forums (including other industries), and creation of Listeria-specific food safety committees.


In Western NY packinghouses, we will have one or more similar cleaning and sanitation workshops this spring. If you are willing to open up your facility to other competitors for the safety of the industry, please contact Craig. We can discuss prior any questions, problems, or concerns you may have. In addition, I would like to visit each packinghouse individually for a consultation and would be willing to work on a facility-by-facility basis with you to perform similar workshops if time allows. Stay tuned to LOFP for updates.