The Center for Produce Safety (CPS) held its 9th Annual research symposium in Charlotte, NC in June 2018. In November 2018, CPS, United Fresh, Western Growers and Produce Marketing Association partnered to conduct a webinar highlighting the key learnings from the symposium and to answer questions from the audience. The recording of that webinar can be found on pma.com. Additionally, the research summaries of all the research projects presented at the 2018 CPS Symposium can be found on the CPS website.
As we prepare for the 2019 CPS Symposium in Austin, TX in June (link to registration page), I was reminded that I had not yet written down my key takeaways from the 2018 CPS Symposium. Since I have performed that task for the previous eight symposia, I thought I would take this opportunity to do so again, especially since some of these research findings are particularly relevant, given the illness outbreaks and consumer advisories of the last year and the upcoming research presentations scheduled for the 2019 symposium. Below are some of the findings that stood out in 2018.
Agricultural water remains a key area of industry operational focus and research. Understanding the potential risks associated with different water sources, irrigation water delivery systems and the environmental influences on the microbial quality of open water sources and the impact that can have on the safety of the product if the water contacts the edible portions of the plant are critical. The environment agricultural water passes through and weather events prior to irrigation can impact the microbial quality of the water and should be part of any decision-making process on whether to irrigate with specific open water sources.
Wash or cooling water control is a multi-variable process and it is important for operators to validate or prove that their preventive controls are effective in killing pathogens. It is equally important to verify that the disinfection process is properly controlled and operated according to the process parameters you set every day.
Validation is such an important concept for the industry. When performing validation experiments to prove the efficacy of a preventive control, operators should be sure that the indicators or surrogates they use are authentic and that they are grown in such a way that puts them in the same physiological state as they would be in if they were in one of our production environments. Often pathogens on a fruit surface or in a drain in a cooling operation are physiologically stressed, i.e. they are not in their ideal environment for survival, so they slow their physiology and turn on defense mechanisms to protect themselves. Sometimes these defense systems also make them more resistant to disinfectants. We want to be sure to have them in this state when we validate treatments to kill pathogens, so we are setting metrics when they are the toughest to kill.
It is generally impossible to use live pathogens for validation studies so non-pathogen alternatives are critical. Several projects in 2018 reported results in the search for indicators of fecal contamination and
E. faecium NRRL B-2354 was described as a useful indicator for Salmonella and demonstrated to be effective in validation of poultry litter heat treatments.
Listeria monocytogenes (Lm) remains an important area for creating awareness and inciting action in the produce industry. The Lm-focused research programs presented in 2018 at the CPS Symposium cut across several commodities and packinghouse configurations but, in the end, it was clear that operators need to have strong and aggressive sanitation programs and robust environmental monitoring programs (EMPs). Part of a strong sanitation program is understanding the niches within your operation where Lm might take up residence and being prepared to eliminate them. A strong EMP means designing sampling programs that are designed to find Lm if it is there, i.e. sampling places and locations where Lm might escape sanitation chemicals or locations where if Lm was there it might be able to contact the food (e.g. zone 1). An important aspect of sanitation whether at the harvest equipment level on the farm or the display case level at retail is to perform cleaning right after operations end for the day as pathogens are harder to eliminate the longer they are permitted to reside with other organic matter on the surfaces of equipment. It is also important to permit appropriate residence time for sanitizers on cleaned surfaces to permit elimination of pathogens.
Read the full report
to take a deeper dive into the 2018 research and for a preview of what to expect at the 2019 symposium.