Listeria monocytogenes in ready-to-eat-foods

My original intent was to write an article about how to respond to a regulatory and/or public health crisis involving contamination with Listeria monocytogenes. I will get to that, but first I want to make it clear that the efforts made to avoid Listeria contamination are of the highest importance and may very well prevent regulatory and public health crises. I’ve never been involved in a Listeria recall that couldn’t have been prevented.

It’s been 30 years since the food industry became aware of Listeria monocytogenes and the need to control it in clean room environments and Ready-to-Eat (RTE) food products. I remember the first case involving meat products that occurred in 1989. USDA’s Food Safety and Inspection Service followed the steps that had already been taken by FDA and declared Listeria monocytogenes to be an adulterant in RTE products. At the time, the absolute control of Listeria in plant environments seemed to be an impossible task.

Listeria does pose unique challenges. It likes the cold, wet environment that exists in many food plants. Often, the very things that are done to make plants microbiologically clean successfully eliminate the microorganisms that would otherwise compete with Listeria. Listeria problems do tend to occur in plants that appear to be very clean. Listeria contamination of foods usually occurs as post-processcontamination. When contamination of this type occurs, typically, RTE products are processed using a pasteurisation step and are then recontaminated with Listeria before the product is packaged.

Controlling Listeria to levels that prevent food contamination requires extraordinary efforts and the application of technologies that weren’t available 30 years ago. It’s certainly one of the most difficult challenges the food industry has ever faced.

In my experience the only way to control Listeria in food plant environments, thereby reducing or eliminating the risks of recontamination, is to identify each and every vector of contamination and implement control measures that eliminate Listeria at each point of entry. These include drains, floors, processing equipment, walls, floors and ceilings, refrigeration units and air/particle borne sources. In addition, measures must be taken to prevent the introduction of Listeria by plant workers, inspectors and visitors.

The good news is that technologies are now available to accomplish this level of control. It goes far beyond routine sanitation and employee training. It requires state-of-the-art technologies and advanced applications that fully control each possible vector of contamination.

Improved control of Listeria outgrowth in foods can be achieved through the use of secondary inhibitors. These are usually the salts of organic acids that are added to product formulations. Another unique characteristic of Listeria is its ability to grow under refrigerated conditions in many foods. Sometimes levels of contamination that can’t even be measured when foods are packaged can increase to high levels over weeks or months of refrigerated storage. Secondary inhibitors prevent the potential for outgrowth in these foods and may keep Listeria levels below the detection limit.

Another major change that has occurred over the past years is the availability of technologies to re-pasteurise food products in the consumer package. This can be done using High Pressure Processing (HPP), a technology that involves the application of hydrostatic pressure at very high levels usually for a period of a few minutes. The result of HPP processing is the elimination of any possible Listeria in the consumer package.

Post-process-pasteurisation can also be achieved using thermal processing applied to packaged products. This can be used to re-pasteurise products such as whole deli hams and roast beef. Re-pasteurisation of these types of foods also results in the elimination of any possible Listeria contamination.

By applying extraordinary control measures to address environmental contamination in food plants with technologies such as secondary inhibitors and post-process pasteurisation, the risk of Listeria contamination in all RTE foods can be greatly reduced or even eliminated.

Responding to regulatory and public health crises involving Listeria contamination

Sometimes even the best efforts for control of Listeria aren’t enough. If Listeria monocytogenes are detected in a RTE food product, both FDA and USDA will expect the manufacturer to initiate a Class I recall. Of course, the same is true when a food product is linked to a case or outbreak of foodborne disease.

Just over the past year, several major US food companies, including Blue Bell Creameries, Hot Mama’s Foods and Graystone Foods have faced Listeria recalls. In some cases, companies have managed the crises in ways that minimised the inherent damages associated with food safety related recalls. In other cases, Listeria recalls have led to plant closing and threatened company’s continued existence. The 2011 recall of cantaloupe produced by Jensen Farms resulted in 33 deaths. The owners of the company were prosecuted and sentenced to five years’ probation, six months home detention and were fined for their role in the outbreak.

In my experience, companies can be faced with very similar challenges and respond with decisions that either minimise the effect of a recall or decisions that effectively close the business. In today’s world, bad decisions can even result in criminal prosecution.

These are the things that I believe minimise the effects of a regulatory or public health related Listeria recall:

1. Companies should establish a well-developed crisis management plan well before issues arise. The plan should include the appointment of a crisis management team and pre-existing agreements with a public relations firm, an experienced food attorney and an outside food safety professional. Most companies do not have the internal expertise to optimally deal with a recall. Given the fact that the US Justice Department now reviews food safety cases for possible criminal prosecution, especially when consumer deaths occur, I also recommend that the crisis management team have access to a criminal attorney to assure compliance with federal laws and regulations.
2. Effective trace back capabilities are essential in limiting the scope of recalls. When a recall occurs, the first order of business is to notify the public regarding which products are being recalled and then to get those products off the shelf and back under company control. When recalls balloon into enormous quantities, it’s generally because plants can’t identify the specific production lots that are implicated. Regulators always err on the side of public health. This means that if the specific lots can’t be identified, then all possible lots are recalled.
3. The effectiveness of crisis management plans and traceability systems should be tested through mock recalls. If weaknesses are identified in a mock recall, corrections can be implemented before an actual recall occurs.
4. When a recall does occur, the crisis management team must cooperate fully with the appropriate regulator agency and public health organisations. 100% transparency with regulators is essential.
5. The public relations aspects of the recall should convey that the company is committed to protecting its customers by removing the affected product from commerce and has brought in the necessary technical resources to solve the problem. These will help restore consumer confidence. Again 100% transparency with consumers and the media is essential. If the company has a social media presence, this provides an excellent way to communicate and inform consumers and the media.
6. After the recall is in effect, consumers have been notified and the process of removing product from commerce is underway, efforts should be made to identify the root cause of the Listeria contamination and develop a corrective action plan. It’s also important that the establishment produce records to show that the operation has been running under control with respect to Listeria contamination in the plant environment. If there’s a doubt about whether the plant has maintained sanitary conditions, the scope of the recall can be greatly increased.
7. Following the development and acceptance of the Corrective Action Plan, steps should be taken to implement it and to verify its effectiveness. The verification should include a comprehensive microbiological mapping evaluation of the facility. The sooner the corrective action plan is implemented and verified, the sooner the plant will be back in production.
8. When the recall and corrective action activities are complete, I recommend that the company communicate that information to consumers and the media. Again, social media provides an excellent vehicle to do this.

These steps will likely minimise the effects of a Listeria recall. Some of the things that can expand the scope and damage inflicted by a recall include a lack of transparency or even intentional deceit. When regulators uncover these types of activities, the continued existence of a company is in real jeopardy. Criminal prosecution is also likely. I have seen firsthand how poor decisions of this type led to the demise of a large national meat business.

Another negative factor is the lack of a pre-appointed crisis management team and crisis plan. Recalls happen without warning and leave very little time for organised reactions. If a company isn’t proactive, there simply isn’t time to organise an appropriate and effective response. As a result, mistakes are made and the scope and seriousness of the recall is exacerbated.

I want to reiterate that similar circumstances surrounding Listeria recalls can result in vastly different consequences depending on the decisions that are made under highly stressful circumstances. Recalls are never painless. However, they can result in minimal permanent damage and may even lead to improved control strategies and safer products.

A recall can also lead to the worst imaginable consequences, including criminal prosecution. It all depends on whether a company is sufficiently prepared and has the expertise on hand to guide the decision making process in a way that satisfies regulators, public health officials, the media and consumers.

Author Biography

Dr. James Marsden has over 40 years’ experience in the food industry with a strong background working with government officials, regulators, food companies, trade associations and in academia. He advised the White House on food safety and nutrition and testified on numerous occasions to the United States Congress, the US Food and Drug Administration (FDA) and the US Department of Agriculture (USDA). After working for several food companies and technology providers, he served as Vice President for Scientific Affairs at the American Meat Institute and President of the AMI Foundation. In 1994, he became the Regent’s Distinguished Professor of Food Safety and Security at Kansas State University. He has extensive experience as an educator, inventor and researcher.