Recent Listeria monocytogenes outbreaks underscore the critical importance for meat and poultry processors to take into account the unique challenges they face in combatting the food safety threat that the pathogen poses.

Among the unique challenges interventions against Listeria present for meat and poultry processors is that Listeria monocytogenes is resilient to cold and has a preference for moist environments, two things commonly found in processing plants, said Christian Calix, vice president of quality for Universal Pure. Even after cooking, contamination can occur if post-cooking handling practices aren’t carefully controlled, making Listeria especially concerning for ready-to-eat products.

"There is still risk even with strong Good Manufacturing Practices and environmental monitoring programs," Calix said. "Its persistence in production facilities, low infectious dose and adaptability to cold temperatures contribute to its impact."

High pressure processing services provider Universal Pure is a founding member of the Cold Pressure Council, which recently wrote a letter (Page 1 and Page 2) aimed at the RTE protein industry, specifically deli meat, regarding the recent Listeria outbreaks. The letter's focus was to educate manufacturers and consumers on the benefits of HPP for this product category.

"HPP has long been recognized by Food Safety and Inspection Service and other regulatory agencies as a viable post-lethality treatment for the control of Listeria monocytogenes in RTE meat and poultry products," Cold Pressure Council Chairman Rick Marshall said in the letter. "The process not only reduces the risk from environmental contamination, such as slicing and other equipment, but also from contamination in under-processed products."

HPP uses water and pressure — no heat — so it preserves a product's flavor, texture and nutritional profile. Unlike thermal preservation methods that can destroy vitamins and other delicate nutrients, HPP enables products to retain higher levels of these nutrients and enzymes, which naturally preserves taste and texture. In some cases, HPP actually improves the texture of products, acting as a tenderizer in proteins, or an emulsifier in dips and spreads to enhance product viscosity.

"HPP can achieve high log reductions in pathogens, but like most things in life, finding the right balance of pressure and hold time — HPP parameters — for each specific RTE protein, such as pork, beef, chicken, or turkey is key to the product's quality," Calix said. "Manufacturers should always collaborate with their HPP experts or providers to identify these ideal parameters."

While HPP is effective for RTE products, it’s less common than traditional antimicrobials like sodium lactate or diacetate, Calix said.

"However, its popularity is growing among manufacturers seeking clean-label options, as HPP addresses food safety concerns and extends shelf life without chemical preservatives," he said. The benefit of extending shelf life without adding anything to the product or introducing heat offers processors functional production flexibilities.

With HPP, there is no risk of reintroducing environmental variables that meat and poultry manufacturers must manage. The process is applied after products are sealed in packaging, eliminating the risk of post-process contamination, a significant advantage in controlling Listeria, Calix said.