This post is the second in a series of eight over safety in the food manufacturing and processing industries. To view the first post in this series, click here.
Listeria monocytogenes is a common strain of pathogenic bacteria in the food processing and manufacturing industries. Food manufacturers are particularly concerned with Listeria because it’s found almost everywhere, which makes total prevention impossible, and because it can cause serious and sometimes fatal foodborne illnesses. The Centers for Disease Control (CDC) estimates that Listeria causes 1,600 illnesses and 260 deaths per year in the United States alone. People who are pregnant, elderly, or have a weakened immune system are at an especially high risk of Listeria-related illness. Listeria can cause listeriosis, meningitis (a bacterial infection that can cause permanent disability, seizures, and death), endocarditis (an infection of the inner lining of the heart chambers and valves), spontaneous miscarriage or stillbirth, and death.
Why is Listeria so dangerous?
Listeria is often called a “ubiquitous organism” because it can be found in almost any environment. It’s frequently found in raw meat, poultry, milk, vegetables, soil, open water, animal feces, and other common locations. Listeria is also an incredibly durable strain of bacteria; it can survive refrigeration, deep freezing, wide pH ranges, high salt content environments, low moisture environments, and even oxygen-deprived anaerobic environments. Because Listeria is so common, it’s nearly impossible to prevent it from entering your facility. Instead, employers should take care to regularly test food products, prevent the formation of growth niches and biofilms, clean and sanitize all surfaces in the facility, and properly train employees on preventative measures.
How can I prevent Listeria from contaminating food products?
The most effective way to prevent Listeria contamination is to provide all employees with proper training on contamination prevention, cleaning, and sanitizing procedures. Click here for more information on cleaning and sanitizing in food manufacturing. Listeria often thrives on floors, drains, cleaning and washing areas, food contact equipment, walls, ceilings, compressed air and HVAC systems, permeable surfaces, open seams, cracks, crevices, and hard-to-reach or hard-to-clean parts of equipment. Whenever possible, you should eliminate seams in your facility; use special epoxy-coated, seamless walls, floors, and covings. Many facilities also use epoxy coating to seal equipment footings to the floor. You should avoid using wood (including wooden broom and mop handles) in your facility whenever possible, especially in ready-to-eat product areas. When possible, your facility can designate separate carts, forklifts, pallet jacks, trash cans, break rooms, and locker rooms for raw ingredient areas and ready-to-eat food areas to prevent cross-contamination. Pests, such as flies, cockroaches, and mice, can easily transport Listeria throughout your facility, so preventative pest control is essential. Listeria can be killed by cooking or pasteurizing the final product and by thermally sanitizing food contact surfaces.
Listeria is a hardy species of bacteria that’s present in almost all environments. To prevent Listeria from getting into your food products, you should alter your facility’s environment to make it less bacteria-friendly. This includes using special epoxy-coated walls and ceilings, avoiding wood products, and regularly cleaning and sanitizing all drains and surfaces. Employees should be trained on specific Listeria prevention procedures and on your facility’s cleaning and sanitizing guidelines.
For more information, follow these links:
- CDC – Listeria Syptoms
- FoodSafety.Gov – Listeria
- Food Safety Magazine – Listeria Guidance & Best Practices in Produce Facilities
- Wiley Online Library – Biofilm Formation and Control in Food Processing Facilities
SafetySkills covers these topics and more in our Listeria Control in Food Manufacturing course. For more information, click here.