Tag Archives: Listeria monocytogenes

Gina Kramer
Food Safety Think Tank

Activate Your Listeria Mitigation and Control Program

By Gina R. Nicholson-Kramer, Jeff Mitchell
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Gina Kramer

Listeria: It has been in the news and in our food throughout the past year. It has cost companies millions of dollars in recalls, shutdowns and mitigation; it has cost the government thousands of dollars in outbreak investigation, inspection and follow-up; and it has cost millions of dollars in medical bills for victims and for some, it has cost their lives.

I have asked Jeff Mitchell, vice president of food safety at Chemstar, to share his knowledge about Listeria mitigation and control, and to talk about the research that supports the innovative program that Chemstar uses with its customers.

Listeria Mitigation & Control Program

By Jeff Mitchell

Jeff Mitchell, Chemstar
Jeff Mitchell, Vice President of Food Safety, Chemstar

Thus far this year there have been several recalls of ready-to-eat (RTE) foods due to contamination with Listeria monocytogenes. Efforts to prevent contamination of food products with Listeria monocytogenes must be conducted at all levels of production. This is a difficult task given the fact that the bacteria is so widespread in the environment.  Focusing efforts in your process where contamination risk is of greatest concern to the consumer is important.  There is solid evidence that commercially prepared foods that have been contaminated with Listeria monocytogenes has occurred after the food product has been subjected to an initial lethality treatment. The product may be exposed in this area as a result of slicing, peeling, packing, re-bagging, cooling, or other procedures that may expose the product to potential contamination.

Listeria monocytogenes survives extremely well in food processing and retail food preparation environments. It may be introduced into your facility through a variety of routes, including:

  • Raw materials
  • Employees’ shoes or clothes
  • Equipment (boxes, crates, carts)

Controlling traffic flow into critical areas of the process can help reduce the chances of introducing and spreading the organism.

Once Listeria is introduced into the nonsterile environment, retail and factory conditions that promote its growth increase the risk of post-processing contamination. Several factors, including moisture, nutrients, temperature, competitive microflora and pH, affect the growth of Listeria in the food preparation and processing environment.  Moisture is the most crucial factor, as it is essential for microbial growth and is the most easily controlled of the factors.

Listeria tends to form a biofilm to enhance its survival when resident populations become established in the food prep/processing environment. The resident populations that are referred to as “persistent” are not easily eliminated by general cleaning and sanitizing procedures. Biofilm penetration is necessary for removal and inactivation of Listeria. The correct blend of chemical, contact time and agitation will aid in the removal. This combination dissolves the biofilm and the organic material to which it adheres, allowing the sanitizer to inactivate the released, sensitive cells.

 To learn more about Listeria from Gina and Jeff, check out their archived webinar with Food Safety Tech, Preventing Listeria Contamination: A Practical Guide to Food Safety ControlsBiofilm removal is important, because persistent L. monocytogenes can be dispersed from a biofilm into the environment and onto food processing equipment, and non-food contact and food-contact surfaces. Passive dispersal of Listeria can occur by aerosolization from high-pressure hoses or brushing; once aerosolized, Listeria can contaminate other growth niches in the food handling/processing area, eventually contaminating food contact surfaces and food. Another form of passive dispersal is the movement of processing equipment. If a biofilm is present, cells can be released by the movement or vibration of the equipment.

Inactivation of L. monocytogenes in biofilms is an important part of a Listeria control program. Understanding this face prompted our team to perform research with the University of Georgia using a mixed culture biofilm formed by Pseudomonas putida and L. monocytogenes to evaluate the ability of Chemstar’s foaming sanitizer to inactivate L. monocytogenes present in biofilms under realistic use conditions. The results revealed that it provides for a greater than four-log reduction.1

Identifying Listeria in the environment and eliminating the resident populations can reduce the risk of secondary contamination. Once these procedures are established, employee training and environmental monitoring are vital.  An effective Listeria control program requires that employees understand their role in mitigating the spread of Listeria, and management must relay those expectations. Control strategies are not likely to be effective if employees won’t cooperate, or don’t understand what they are expected to do, or why it is important, and that expected procedures or behavior will be monitored.

Reference

  1. Frank, J. and Mitchell, J. (December 3, 2010).  Evaluation of Chemstar foaming sanitizer for inactivating Listeria monocytogene in floor drain biofilms.
Join us for the Listeria Mitigation and Control Workshop at the Food Safety Consortium in Schaumburg, IL on November 17, 2015. Learn about the Five Key Elements in building an effective Listeria Control Program:

  1. Specific Sanitation Controls for Listeria
  2. Training of Personnel (they need to understand their role in the program)
  3. Traffic Control
  4. Targeted Environmental Monitoring and Testing
  5. Control Water Introduced into the Process Environment

The workshop will be a hands-on approach to learning about Listeria and practical solutions to take back and implement into your company’s sanitation program.

Listeria in Retail a Complex Challenge

By Maria Fontanazza
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The presence of Listeria monocytogenes in retail establishments can become a persistent problem. While maintaining vigilant and strict cleaning practices is key to reducing the risk, Haley Oliver, Ph.D., associate professor of food science at Purdue University cautions there is no silver bullet for a cleaning strategy, because every store is different. The rate of Listeriosis has not decreased but rather has plateaued, and controlling Listeria is a growing problem, forcing it to be a hot topic at this year’s IAFP conference.

“Attempting to regulate an industry as broad as retail in the United States is a huge challenge,” said Kevin Smith, Ph.D., senior advisor for food safety at FDA’s Center for Food Safety and Applied Nutrition. According to Smith, more than 2200 agencies are responsible for the licensing and inspection of retail facilities. Due to the massive size of the industry, much of the actions surrounding driving compliance and enforcing regulations occur through state, local, and tribal authorities.

The Food Safety and Inspection Service (FSIS) attributed 83% of Listeriosis cases to deli meats that were sliced at a retail counter, (as opposed to meats prepackaged at a facility). Retailers should be using the FSIS guidelines released in June,  “Best Practices Guidance for Controlling Listeria monocytogenes in Retail Delicatessens“, for specific information about how they can ensure the safety of products such as deli meats. Revisions to the guidance include a clarification that food processing equipment should be taken apart during cleaning and sanitizing; an added recommendation that retailers scrub surfaces during cleaning to prevent biofilm formation; and clarification that retailers rotate sanitizers to avoid development of resistance. According to Kristina Barlow of FSIS, these practices can extend beyond deli meats to any products that are prepared at retail.

Learn more about Preventing Listeria Contamination: A Practical Guide to Food Safety Controls

Date: Wednesday, August 5

Time: 2 pm – 3 pm ET

Barlow outlined areas that the Listeria best practices guidelines address, including:

  •  Product handling. “Use products formulated with antimicrobial agents to prevent growth of Lm—96% illnesses could be reduced if retailers used these products,” said Barlow.
  • Cleaning and sanitizing. It is recommended that retailers develop written sanitation procedures outlining the daily frequency in which utensils and equipment should be cleaned and sanitized. Equipment should be cleaned every four hours, and surfaces scrubbed to prevent biofilm formation. Barlow advised that retailers document all actions they perform to ensure that procedures are carried out each day.
  • Facility and equipment controls. Ensure that the floors, walls and overhead structures are clean. Listeria that is harbored in drains is more likely to creep its way into equipment, and the bacteria can also hide under dust and floors, so it is important to avoid construction when food products are exposed.
  • Employee practices. Use gloves, train in sanitation practices, and make sure that information is available to employees in multiple ways (i.e., other languages and use of images). In addition, implement policies to ensure that ill employees are not working with food; and limit employee traffic in the deli area—develop traffic flow plans for product, employees and other items to prevent contamination by both consumers and employees. Finally, employees should change aprons or other frocks when soiled. “Gone are the days when the butcher is covered in blood [and] serving people,” said Barlow.