Monday, May 13, 2013

Risk Assessment of Listeria in Retail Delicantessens

FDA released the Draft Interagency Risk Assessment – Listeria monocytogenes in Retail Delicatessens Technical Report. ( The goal of this report is to further the understanding of the risk of Listeria monocytogenes that is associated with the retail deli case. Listeria monocytogenes can grow on meat and cheese items that are sold in retail deli establishments. As we know, Listeria can grow at refrigeration temperatures and deli meat products have been involved in past outbreak. Therefore it is important for retail establishments to understand how to best limit the risk of Listeria in their retail cases where there are products with exposure during handling and storage, such as cut luncheon meats.
FDA and USDA evaluated various practices in retail deli operations and came up with some best practices to mitigate the risk of Listeria.
While this is a beast of a report at 179 pages, there are some good takeaways. Here some of the highlights, in more common language. Below this, the conclusion from the report and the USDA news release are also included.
  1. Start with products that have minimal Listeria risk. While selling products that have anti-Listeria agents helps, this is not always possible. But procuring items that have been produced in establishments with good Listeria control programs is important. It is also important to properly handle those products are handled from the time they are made through the time they are brought into the retail deli establishment. Even small amounts of Listeria introduced can have a huge impact over time.
  2. Keep deli retail case temperatures low, certainly below 41 degree F. While Listeria can grow at refrigeration temperatures, it does grow slowly. So the lower below the temperature of 41F, the better.
  3. Clean and sanitize the retail deli units regularly, especially the niches within the cooler….like the drain.
  4. Prevent cross contamination from other sources. Clean the slicers and the utensils regularly. Ensure that employees are washing hands and wearing gloves.
  5. Remember that items that do not allow the growth of Listeria can be sources of contamination. For example, most fresh produce items which does not support the growth of Listeria can still be the source of contamination for meat items that will support growth. So put controls in place for handling and storage of those types of items.
  6. If pre-slicing, pre-slice on a clean slicer. ( I am not a fan of pre-slice meat, I prefer sliced to order).
Conclusions from the report.
This QRA represents the first large-scale effort to model L. monocytogenes cross contamination at retail. The risk assessment model contributes to our understanding of L. monocytogenes transmission, survival, and growth in the retail environment and was used to evaluate how retail practices may impact the predicted risk of listeriosis. The approach used was to evaluate the public health effect of various mitigations under six different baseline conditions that may characterize a retail deli and the RTE food its serves.
The key findings from this assessment of risk of listeriosis associated with RTE foods prepared and served in retail deli operations include:
• Control Growth. Employing practices that prevent bacterial growth dramatically reduced the predicted risk of listeriosis, as observed in other L. monocytogenes risk assessments. The use of growth inhibitors for suitable products prevents growth of L. monocytogenes in RTE foods both at retail and during consumer home storage, leading to an overall dramatic reduction in the predicted risk of listeriosis (ca. 95%, see table). The strict control of temperature during refrigerated storage in retail delis did reduce the predicted risk. The impact of this control is nevertheless lower as it reduces growth only during this specific storage (5-20% reduction according to the baseline and the scenario) (cf. “Temperature Control” baseline and growth inhibitor scenarios).
• Control Cross Contamination. Cross contamination of L. monocytogenes in the retail environment dramatically increases the predicted risk of listeriosis. Cross contamination during the routine operation of the retail deli is not amenable to a simple solution (cf. “Transfers and Slicer to 0” scenarios).
• Control Contamination at its Source. Increasing the concentration and transfers of L. monocytogenes from incoming products, the environment, or niches directly increases the predicted risk of illness. Increasing L. monocytogenes concentration in incoming product increased the predicted risk of listeriosis whether or not the contaminated RTE product itself supported growth. The increase in predicted risk was greater when the equivalent contamination occurred on product that supported the growth of L. monocytogenes (cf. predicted risks for “Incoming Growth Chub” baseline and “Incoming Non-growth Chub” baseline, as well as “Reduce Level” scenarios).
 • Continue Sanitation. Sanitation practices that eliminate L. monocytogenes from the deli area food contact surfaces results in a reduction in the predicted risk of illness. Cleaning and sanitizing food contact surfaces reduced the predicted L. monocytogenes levels in the deli area (cf. “No Sanitation” scenario). Wearing gloves while serving customers reduces the estimated risk of listeriosis.
• Identify Key Routes of Contamination. The slicer (for deli meats and cheeses) and the salad utensils (for deli salads) are sources of L. monocytogenes cross contamination to RTE foods. Control of L. monocytogenes cross contamination at these points during retail preparation and handling of RTE foods reduced the predicted risk of listeriosis (cf. “Transfers to 0” versus “Transfers and Slicer to 0” scenarios).
In summary, this risk assessment improves our understanding of L. monocytogenes in the retail deli and should encourage improvements to retail food safety practices and mitigation strategies to further control L. monocytogenes in RTE foods. The ‘what if’ scenarios modeled in this risk assessment provide insight on how cross contamination, sanitary practices, and temperature control impact the predicted risk of listeriosis. This risk assessment is based on an extensive amount of information gathered through partnerships with academia and input from stakeholders. Additional data would be useful to refine and improve the predictions made by the “Virtual Deli” model. Additional data would be useful to further explore how more specific retail practices and conditions (e.g., equipment design) impact the risk of listeriosis.
New Study by USDA, FDA Aims to Enhance Food Safety in Retail Delis
Risk Assessment Targets Listeria monocytogenes (Lm)
WASHINGTON, May 10, 2013 - To help minimize the public health burden of listeriosis, USDA's Food Safety and Inspection Service (FSIS) and the U.S. Food and Drug Administration (FDA) have conducted a major study to better understand the risk of foodborne illness associated with eating certain foods prepared in retail delicatessens and developed recommendations for changes in current practices that may improve the safety of those products.
The study, a quantitative risk assessment, provides a scientific evaluation of the risk of listeriosis associated with consumption of meats, cheeses and other ready-to-eat foods prepared in retail delis. It also examines interventions that limit the survival, growth or transmission of Listeria monocytogenes (Lm), the bacteria that causes listeriosis.
Control of Lm has long been an objective of the public health community. The Centers for Disease Control and Prevention estimates that infections with Lm causes about 1,600 illnesses, 1,500 hospitalizations and 260 deaths in the United States each year. Listeriosis is rare, but its fatality rate is very high (i.e., about 16 percent, compared with 0.5 percent for either Salmonella or E. coli O157:H7). It primarily affects older adults, pregnant women, newborns and adults with weakened immune systems.
"The risk assessment will be a tremendous asset in our efforts to reduce the 1,600 illnesses and 260 deaths attributed to this pathogen annually," USDA Under Secretary for Food Safety Dr. Elisabeth Hagen said. "Essential information has been gained from these findings, including the fact that once Lm enters a retail environment, it has the potential to spread due to cross contamination. This assessment highlights the importance of our work to prevent Lm from entering the retail environment in the first place, and provides a significant tool towards this effort to protect consumers and prevent foodborne illness."
The U.S.-focused study is the first of its kind. It quantitatively links retail deli practices to predicted public health outcomes, which has never been done before. The study is based on observations of deli employees' work routines; concentrations of Lm on incoming products and in the deli environment; simulations of the bacteria's transmission, such as from slicer to food; and dose-response modeling. The study was designed to apply to a range of deli establishments, from small independent operations to the deli departments in large supermarkets.
The study also reinforces the importance of FDA's Food Code recommendations to operators of retail delis. State, local and tribal jurisdictions can do their part to reduce listeriosis by enforcing all relevant provisions of the Food Code as part of their own food safety requirements.
No single intervention will put an end to Lm in food sold at retail delis, the study found. Instead, there are many steps that retail deli operators and their suppliers can take to help reduce listeriosis. The study's key findings include:
Storage temperature. If all refrigerated, ready-to-eat foods are stored at 41 degrees Fahrenheit or below, as the FDA Food Code recommends, at least 9 of every 100 cases of listeriosis caused by contaminated deli products could be prevented.
Growth inhibitors. If all deli products that support Lm growth were reformulated to include growth inhibitor, 96 of every 100 cases of listeriosis caused by contaminated deli products could be prevented. While this finding is significant, the actual benefit may be smaller in part because growth inhibitor may be used in concentrations not effective throughout the shelf life of a food, and it can affect the flavor.
Cross contamination. The predicted risk of listeriosis dramatically increases in retail delis as a result of cross contamination, with slicers remaining a particular challenge. Cross contamination is particularly difficult to eliminate, but the study shows proper cleaning and personal hygiene makes a difference.
Contamination of Incoming Product. If current levels of Lm in ready-to-eat foods received by the retail deli from processing establishments were reduced by half, 22 of every 100 cases of listeriosis caused by contaminated deli products could be prevented. This finding suggests that continued efforts to prevent low levels of Lm contamination during processing, even on products that do not support growth of the pathogen, reduces the risk from these products and other ready-to-eat foods that can be subsequently cross contaminated in the retail delicatessens.
FDA and FSIS have taken many steps to enhance retail food safety in an effort to reduce listeriosis and other foodborne illnesses. For instance, since its initial release in 1993, the FDA Food Code has been revised to target Lm prevention, including more stringent temperature controls for refrigerated foods and limits on how long such foods can be retained after opening or preparation.
In addition, FDA has created educational materials in recent years to support foodservice operators, including guidance on how to keep deli slicers properly cleaned and sanitized, a handbook on employee health and personal hygiene, food-safety posters in nine languages, and video testimonials designed as training aids. FSIS is planning to provide outreach materials to retailers where ready-to-eat meat and poultry products are sliced, prepared, or packaged for consumption in the home. These materials will highlight risky practices based on the results of the interagency risk assessment and help retail establishments to adopt best practices that could decrease the potential for Lm growth or cross contamination.
Consumers, too, have a role to play in reducing listeriosis. For advice on keeping refrigerated foods cold, cleaning one's refrigerator regularly, and cleaning hands and kitchen surfaces often, visit To further minimize any risk of listeriosis, FDA and FSIS recommend that older adults, pregnant women and adults with weakened immune systems reheat hot dogs and lunch meats until steaming hot.
The study was published today and can be read in its entirety on either the FDA or FSIS web sites. A public meeting to discuss the study and its findings will be held at USDA's Jefferson Auditorium at 1400 Independence Avenue, Southwest, Washington, D.C., on May 22nd, from 8:15 a.m. to 4:15 p.m. People who plan to attend the meeting are asked to register in advance at FSIS' website.
The risk assessment is in addition to other significant public health measures FSIS has put in place during President Barack Obama's Administration to date to safeguard the food supply, prevent foodborne illness, and improve consumers' knowledge about the food they eat. These initiatives support the three core principles developed by the President's Food Safety Working Group: prioritizing prevention; strengthening surveillance and enforcement; and improving response and recovery.

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