Listeria monocytogenes was the largest cause of all food and beverage recalls in the United States over the past 20 years, according to “An Analysis of Food Recalls in the United States, 2002–2023,” which was published in the December 2024 issue of Journal of Food Protection. The omnipresent pathogen accounted for 7,844 recalls: 22% of total recalls and 45% of biological contamination recalls. More than 60% of foods recalled for contamination by L. monocytogenes were processed in some form, and almost 70% were chilled or frozen products. Some of the highest risk categories were, and continue to be, deli-style ready-to-eat meats sold as stand-alone products, as well as included in chilled sandwiches, salads and other ready meals.
“The presence of some severe biological contaminants, such as Listeria, are not allowed at any level in food products,” said John DeBeer, a retired food safety executive based in Encinitas, Calif., and lead author of the paper. “The food processing area also has zero tolerance for these bacteria that are known to cause illness and even death. Any presence of these pathogens on or in the food or food contact surfaces is considered adulteration and can force a recall.”
Eighty-eight percent of the Listeria recalls analyzed in the paper were categorized as Class I. This means that “a reasonable probability exists that the consumption or exposure to a noncompliant food product will result in severe adverse health effects or death,” according to the US Food and Drug Administration (FDA).
“Despite being a relatively recent development, an emphasis on food safety culture is and has been vital in preventing recalls and other food safety incidents,” said DeBeer. “Food producers must develop and cultivate strong food safety cultures throughout their facilities and supply chains, surpassing mere compliance with minimum requirements. A preventive, safe process is critical to manufacturing food and providing sanitary procedures to maintain the cleanliness of the manufacturing areas and keep the food-contact surfaces clean and food safe.”
To further ensure safety, ingredient intervention is incorporated into the process. That’s because Listeria thrives in refrigerated environments and survives in food processing facilities posing a constant challenge to food safety. Its high mortality rate, particularly among vulnerable populations, makes the elimination of Listeria from food products crucial for public health and to prevent costly recalls.
“Listeria doesn’t come from the raw material,” said Laurent Dallaire, chief executive officer and co-founder, Innodal, Quebec, Canada. “It happens during cutting, slicing, packaging, etc.”
Prepackaged deli meats that are processed and sealed in a controlled environment offer the highest level of protection, according to experts. (Source: ©PHOTOPAPER - STOCK.ADOBE.COM)Significant threats
Ready-to-eat deli-style meats are at risk of contamination from Listeria at the processing facility, behind the deli counter and even at home when products are opened and returned to the refrigerator multiple times. Heating the product to 165°F or higher will kill Listeria, but most consumers are not doing that with their ham and cheese on rye.
Further, many of today’s busy consumers shop less frequently for food and buy more, especially when items are on sale. They rely on larger package sizes, longer storage times and cost-effective purchasing strategies.
“With food prices soaring in recent years, the pressure to waste less, cook at home and stretch every dollar has intensified,” said Derek Hull, director of technical services, Wenda Ingredients, Naperville, Ill. “Fully cooked, ready-to-eat meats offer consumers a convenient way to enjoy high-quality, flavorful foods with minimal preparation. This convenience comes with an increased food safety risk.
“While pathogens like E. coli, Salmonella and Clostridium are also risks, Listeria receives the most attention because it can thrive in cold temperatures, has a low infectious dose, it poses significant risk to pregnant women and is widely present in the environment,” added Hull. “Deli-style cut-to-order meats, pose the highest risk. Employees are responsible for equipment sanitation, proper food handling and personal hygiene. Deli meats are constantly moved in and out of refrigeration, sliced on shared equipment that is often used for cheese and other products and handled by multiple employees. Storage cases are frequently opened, closed and touched, further increasing the risk of contamination. Additionally, sanitation is managed at the store level, where cleaning practices may be inconsistent and less rigorously inspected.”
Each interaction with the product presents an opportunity for microbial transfer. By incorporating proven food safety ingredient interventions, manufacturers can safeguard product quality, extend shelf life and ensure consumer safety.
“Prepackaged deli meats, which are processed and sealed in a controlled manufacturing environment, generally offer the highest level of protection,” said Garrett McCoy, senior manager, research, development and applications, Corbion, Lenexa, Kan. “These products still can be affected by external factors such as temperature fluctuations during transportation, storage conditions at retail and on-shelf placement. Since every instance of handling and exposure increases the potential for contamination, incorporating antimicrobial ingredients — whether conventional or clean label — provides an added layer of protection that extends beyond sanitation and process controls. Regardless of format, maintaining a strong defense against microbial growth is essential to ensuring food safety and consumer confidence.
“Vinegar or cultured sugar, for example, can control the outgrowth of pathogens should contamination occur,” McCoy said. “Vinegar has become widely used in the food industry in efforts to provide food safety in clean-label formulas. Cultured sugar also may be used to inhibit the outgrowth of Clostridium in uncured products, while providing greater spoilage control than vinegar alone.”
Hull added, “The clean-label movement has driven the industry to shift away from traditional chemical preservatives like lactate and diacetate in favor of more natural alternatives. One of the most common solutions on the market today is buffered vinegar, which is available in both dry and liquid forms.
“Under US regulations, these products can simply be labeled as ‘vinegar,’ making them a clean-label-friendly choice,” Hull said. “However, vinegar is not a magic bullet. Some acid-tolerant bacteria, such as lactic acid producers, can survive and even thrive in the presence of organic acids.”
Intervention innovations
Lactic acid bacteria produces acids that lower pH, potentially altering the product’s flavor and creating an undesirable sour taste. They can also generate gas, leading to package bloating.
“In some cases, they cause milky purge (excess liquid release) and even slimy textures, making the product unappealing,” Hull said. “To address these issues, processors and ingredient innovators are exploring new ways to reduce spoilage organisms while maintaining pathogen control.”
Wenda Ingredients has focused its research on nature-inspired solutions, leading to the development of a bacteriocin-based line of food safety ingredients.
“In nature, bacteria compete for resources,” Hull said. “When threatened or stressed, some bacteria trigger a host defense mechanism-producing bacteriocins. These are peptide proteins that essentially signal ‘This is my food and water.’ These naturally occurring compounds are highly specific, targeting only competing bacteria without harming beneficial organisms.”
Wenda’s new ingredient provides a multi-layered protection system. It is labeled simply as “onion powder and vinegar.”
“Used at low levels, typically 1% to 1.5%, it delivers significant protection without altering taste or texture,” Hull said. “This combination results in a protection system greater than the sum of its parts.”
The optimal usage level of any food safety ingredient depends on the specific application and target shelf life. Ingredients and technologies may work in synergy, enhancing efficaciousness while lowering usage levels.
Prosur Inc., Naperville, Ill., offers proprietary blends of natural fruit and spice extracts that allow processors to eliminate undesired chemicals, such as sodium nitrite, for flavor and color stabilization, shelf life and protection from spoilage microbes and pathogens. These clean-label alternatives are used in sous-vide cooked meat and poultry, as well as ready-to-eat meats and plant-based alternatives.
“Fruits and spices naturally contain these incredibly beneficial compounds called polyphenols,” said Simon Claessens, Global Business Director at Prosur. “Apart from mimicking the sensory profile of conventional nitrite-cured meats, they are known to effectively delay spoilage, keep the red color of meat during processing, and protect foods from pathogens. Multiple direct and synergistic mechanisms work at the cellular level of certain pathogens, such as Listeria monocytogenes or Clostridium botulinum, triggering cell lysis. Coupled with dried vinegar, these blends have been proven to provide cooked meat and poultry products with 90 to 120 days of shelf life.”
Food safety is not only important to human well being but also to the longevity and reputations of food producing companies. (Source: ©PHOTOGRAPHEE.EU - STOCK.ADOBE.COM)Intervention options
Suppliers may also assist with finding the ideal ingredient solution. Corbion, for example, helps processors take a proactive approach with its Listeria Control Model. This predictive tool allows processors to input key product characteristics and determine how different antimicrobial use rates impact Listeria control over time. The model then generates an easy-to-read report that can serve as scientific support for food-safety programs.
“Importantly, the tool aligns with the US Department of Agriculture’s Food Safety and Inspection Service’s guidelines on controlling Listeria in post-lethality exposed, ready-to-eat meat and poultry products,” McCoy said. “According to these guidelines, establishments can use predictive modeling results to meet the first part of validation — scientific support — helping processors demonstrate compliance with regulatory requirements. By combining predictive microbiology with proven antimicrobial solutions, Corbion equips meat processors with the data-driven insights needed to enhance food safety, extend shelf life and ensure consumer protection.”
A new technology recently became available to US processors. In September 2024, FDA and USDA granted Generally Recognized as Safe (GRAS) status to a food processing aid designed to eliminate Listeria. It has been commercially in use in Canada for the past four years. Developed by biotech company Innodal, the technology uses antimicrobial peptides to eliminate the harmful pathogen. With this approval, Innodal is set to launch industrial-scale projects with US processing companies, marking its entry into the US market.
The technology is based on pediocin, a peptide consisting of 44 natural amino acids. It acts to destroy Listeria by permeating their cell membrane, according to Dallaire.
“It is applied at very, very low levels and does not impact sensory properties,” said Dallaire. “It comes in customized pre-dosed vials to remove human error in measuring. This eliminates the risk in underdosing.”
Application of pediocin varies by product. With ready-to-eat meat and poultry, a diluted solution can be manually or robotically sprayed on the surface right before packaging. This clean-label, natural solution preserves the taste, color and texture of food. As a recognized processing aid, the technology can be used by processors without requiring ingredient label updates, simplifying operations and minimizing waste.
“Beyond enhancing food safety, many of these ingredients provide additional functional and sensory benefits,” McCoy said. “Corbion, for example, has developed proprietary vinegar technology to allow for sodium reduction in formulas without sacrificing shelf life or flavor. Fermentation-derived ingredients, such as cultured sugar, can enhance flavor, enabling manufacturers to reduce sodium levels without compromising taste. These multifunctional advantages allow manufacturers to produce safer, high-quality products that align with consumer expectations.”
Demands will continue to be placed on the global food supply chain. Because food safety is paramount for survival of both humans and brands, ready-to-eat meat and poultry processors will want to include proven, effective, clean-label ingredient technology to eliminate pathogens.
