Ask The Expert: Summary of the Six Article Series on Listeria in Food Plants

Article By Bob Lijana Published December 31, 2025
Article Source: https://foodsafetytech.com/column/summary-of-the-six-article-series-on-listeria-in-food-plants/amp/

Over the past six months we have shared a series of articles on many practical aspects of managing Listeria. A summary of each of these articles follows immediately below after their respective titles. In addition, we have added a list of additional references on this subject. Links to all the articles in the series are in the Related Articles section below

What is Listeria: Listeria monocytogenes is one of the most virulent food-borne pathogens. It is an extremely strong organism, able to survive a wide pH range and a wide temperature range. These survival characteristics make Listeria a very insidious organism. Just because a food is cooked or has preservatives or has a low pH doesn’t mean that Listeria is not present—it’s quite the tough organism. Assume it’s there.

Listeria-Related Regulations (FDA & USDA): FDA and USDA have an essentially “zero tolerance” policy for Listeria monocytogenes in foods. However, in spite of past mistakes and costly recalls, Listeria-related recalls still occur. All regulations preach an ongoing vigilance to Listeria presence in the plant environment and in the food. Regulators also use DNA testing to find root sources of Listeria, which can prevent untold tragedy. Regulations help protect public health, so they should be used to that end.

Where Listeria Comes From, and How It Moves Around: Listeria is widely distributed in nature, found in soil, water, vegetation, and animal feces. Thus, it is quite easy for it to get into food plants and be transported around that plant. Given this, a wise food safety team always assumes that the organism is present somewhere in the plant. Harborages are all areas in which Listeria can grow; movement vectors are where those harborages intersect with people and equipment moving around. Best practices necessitate that harborages are eliminated and movement vectors are identified and controlled.

How to Find Listeria in the Plant: before you sample for Listeria, make sure senior management across all functions is supportive of this task, and is willing to share the risk of actually finding Listeria. Some companies test for Listeria species, and some test for a marker organism to avoid a zero-tolerance panic. Best practice is to establish, validate, and execute an environmental monitoring program which is based on strategic sampling of sites around the plant. Doing so is hard work, and requires a lot of patience since Listeria is notoriously hard to find.

How to Get Rid of Listeria in the Plant: there are two complementary approaches to managing Listeria: keep it out to begin with, and eradicate it when it is found. Keeping it out is hard, but try anyway—use interventions such as clean uniforms, captive footwear, and sanitizing mats prior to entry into production. And killing it—involve a reputable chemical company who understands food production. Use quaternary ammonium compounds judiciously, strategically, and smartly. Remember, you are rarely ever done!

Communication—The “Choice to Chase”: deciding to “chase” Listeria is a cross-functional decision, residing not only with the Food Safety & Quality Assurance team. Everyone buys in to be educated on actions and consequences, and to share the risk. The overall food safety culture needs to be one of honesty and openness in communication. A culture of support across the board matters significantly to making sure Listeria is managed well. This is also the kind of environment that FSQA professionals can be proud of, knowing they are making a very positive impact on public health and trust.

REFERENCES

1. Butts, J. 2003. Seek & Destroy: Identifying and Controlling Listeria monocytogenes Growth Niches. Food Safety Magazine. 9 (2). Available at: https://www.food-safety.com/articles/4802-seek-destroy-identifying-and-controlling-listeria-monocytogenes-growth-niches.

2. CDC. 2016. Etymologia: Listeria. 22(4). Available at: https://wwwnc.cdc.gov/eid/article/22/4/ET-2204_article.

3. Cornell University and 3M. 2019. Environmental Monitoring Handbook for the Food and Beverage Industries. Available at: https://www.idfa.org/wordpress/wp-content/uploads/2020/03/3m-environmental-monitoring-handbook-09-2019.pdf.

4. 2008. Compliance Policy Guide CPG Sec 555.320 Listeria monocytogenes. Available at: https://www.fda.gov/regulatory-information/search-fda-guidance-documents/cpg-sec-555320-listeria-monocytogenes.

5. 2017. Draft Guidance for Industry: Control of Listeria monocytogenes in Ready-to-Eat Foods: Guidance for Industry. Available at: https://www.fda.gov/regulatory-information/search-fda-guidance-documents/draft-guidance-industry-control-listeria-monocytogenes-ready-eat-foods.

6. 2020. Get the Facts About Listeria. Available at: https://www.fda.gov/animal-veterinary/animal-health-literacy/get-facts-about-listeria

7. 2022. BAM Chapter 10: Detection of Listeria Monocytogenes in Foods. Available at: https://www.fda.gov/media/157717/download.

8. Foundation for Meat & Poultry Research & Education. 2021. Food Safety Equipment Design Principles. Available at: https://www.meatinstitute.org/sites/default/files/original%20documents/Sanitation%20booklet%202021.pdf.

9. Jay, J., Loessner, M., and Golden, D. 2005. Modern Food Microbiology. Available at: https://link.springer.com/book/10.1007/b100840.

10. Jespersen, L., Butts, J., Holler, G., Taylor, J., Harlan, D., Griffiths, M., and Wallace, C. 2019. The Impact of Maturing Food Safety Culture and a Pathway to Economic Gain. Food Control. 98:367-379. Available at: https://www.sciencedirect.com/science/article/abs/pii/S0956713518305863.

11. Lijana, B. 2021. Whole-Genome Sequencing: A Double-Edged Sword for the Food Industry. Food Quality & Safety. Available at: https://www.foodqualityandsafety.com/article/opinion-whole-genome-sequencing-is-a-double-edged-sword-for-the-food-industry/

12. Lijana, B. 2024. Checklists: Useful Tools or Traps? Food Safety Tech. Available at: https://foodsafetytech.com/feature_article/checklists-useful-tools-or-traps/

13. National Fisheries Institute. 2019. Ready-to-Eat Seafood Pathogen Control Guidance Manual. Available at: https://aboutseafood.com/wp-content/uploads/2018/09/3rd-Edition-RTE-Manual-Final-3-15-19.pdf.

14. Powitz, R., Balsamo, J., Coleman, N., Collins, C., Noonan, G., Radke, V., and Treser, C. 2025. Complexities and Strategies for Controlling Contamination. Environmental Health. 87(6):32. Available at: https://www.researchgate.net/publication/390360674_Complexities_and_Strategies_for_Controlling_Contamination.

15. SQF Institute. 2020. Food Safety Code: Food Manufacturing. Edition 9. Available at: https://www.sqfi.com/docs/sqfilibraries/code-documents/edition-9/code-pdfs/20227fmin_foodmanufacturing_v3-2-final-w-links.pdf?sfvrsn=7f70c75a_8

16. FSIS Compliance Guideline: Controlling Listeria monocytogenes in Post-lethality Exposed Ready-to-Eat Meat and Poultry Products. Available at: https://www.fsis.usda.gov/sites/default/files/import/Controlling-Lm-RTE-Guideline.pdf.

17. Zoellner, C., Ceres, K., Ghezzi-Kopel, K., Wiedmann, M., and Ivanek, R. 2018. Design Elements of Listeria Environmental Monitoring Programs in Food Processing Facilities. Comprehensive Reviews in Food Science and Food Safety. 17: 1156-1171. Available at: https://pubmed.ncbi.nlm.nih.gov/33350161/.