Process and Operations / Food Safety / Technology

High-Pressure Pasteurization, Other Technologies, Drive Improvements In Ready-To-Eat Meats

Extended shelf life, a clean label and quality assurance for ready-to-eat meats are benefits with appeal to processors, and high pressure is one of the technologies that deliver them.

By Kevin T. Higgins, Managing Editor

Invisible Sentinel

A scientist at Invisible Sentinel prepares a sample at the firm’s Philadelphia headquarters. The company produces rapid diagnostic kits for Listeria and salmonella detection.

Biological contamination concerns every food processor, although makers of ready-to-eat (RTE) foods face the greatest challenge in combating naked-to-the-eye enemies of safe food.

Guidelines from USDA’s Food Safety Inspection Service deal at length with performance standards for various products in terms of Salmonella control, E. coli O157:H7 elimination and Clostridium botulinum safeguards. Listeria monocytogenes, on the other hand, is in a category all its own.

The most lethal of the food pathogens, the bacteria associated with Listeriosis in humans is termed by FSIS “a formidable pathogen” because of its tolerance for heat, cold, sodium and other barriers sufficient to control other food-safety threats.

The danger of post-lethality contamination by this pathogen prompted the agency to issue specific compliance guidelines for RTE meat and poultry products and to devise a three-tier system for processing facilities, based on their use of antimicrobial agents and post-lethality treatments.

Of course, most processors want to be in the lowest-risk group, both for the implied seal of approval it carries and because those facilities are subjected to the least FSIS oversight. The challenge they face is the steps they must take can cause quality degradation or ingredient labels that run counter to the clean-label preference of the market.

At deli-beef supplier Vincent Giordano Corp., Philadelphia, “using a lot of preservatives and chemicals” originally helped lock in Alternative 1 status and deliver 45-60 days shelf life, President Guy Giordano reports, but he wanted more. In 2010, Giordano invested $3 million in refrigeration and a 420-liter high pressure processing system from Hiperbaric. The process extended his products’ shelf life to 90 days, “without any sodium or other preservatives. We could go longer, but if you don’t sell it in 90 days, why would you carry it?” he growls.

The 250,000 lbs. of finished goods produced weekly by Giordano isn’t enough to fill up the HPP press’ capacity, so the firm provides tolling service under the name SafePac. Organic juices and other products are becoming a larger share of the throughput, but RTE meats still account for the majority. Antimicrobials are unnecessary “if you can demonstrate a 5 log reduction” of bacterial contamination, Giordano observes, and HPP helps deliver that level of assurance.

Referring to HPP as “the silver bullet,” Giordano believes food safety ranks with price and product quality as a customer consideration, adding, “You’re one recall away from being out of business.”

Technology providers, on the other hand, are focusing on commercial benefits like extended shelf life and the elimination of thermal degradation. “I never like to sell the technology on the basis of food safety,” says Jaime Nicolas-Correa, director of Hiperbaric S.A.’s North American operations in Miami, Fla. “Safe handling is something processors already know.”

Sometimes referred to as cold pasteurization, HPP typically is a post-packaging treatment that holds food in a chamber for several minutes at approximately 85,000 psi, destroying bacteria, viruses and mold. The U.S. Department of Defense, along with private industry, poured millions of dollars into HPP research and development in the early 2000s with the goal of creating a sterilization step that would render low-acid foods shelf stable, without refrigeration.

Although some sterilization work continues, that goal proved impractical. Pasteurization, on the other hand, has gained broad acceptance and growing use, with more than 200 HPP presses in service in the U.S. and Canada.

Two HPP fabricators currently serve the North American market: Avure Technologies Inc., originally a collaboration between Flow Technology and ABB, and Hiperbaric, a Spain-based OEM that has focused on HPP for food since the late 1990s. Nicolas-Correa recalls rudimentary discussions in years past with food professionals who knew almost nothing about the novel technology. “Now, they’re asking the right questions,” he says.

For whom the HPP tolls

HPP at Avure Tech

Larger circumference carriers are helping increase throughput and lower processing costs for HPP pasteurization of ready-to-eat meats and other food products. Photo: Avure Technologies Inc.

Entrepreneurs and start-up ventures fueled much of the early growth in HPP use. Consequently, a national network of tolling services has been created to serve processors’ post-lethality needs, with RTE meats accounting for the bulk of the traffic.

Milwaukee-based American Pasteurization Co. (APC) blazed the tolling trail in 2004 and added a Sacramento, Calif., service center in 2012. Universal Cold Storage in Lincoln, Neb., was among the refrigerated warehouse operators to add HPP as an added service in 2010. Both APC and Universal participate in a lead-sharing and technical support program with Avure.

Cold-storage customers were moving finished goods from Lincoln to HPP centers for treatment and then back to Lincoln for staging and shipping, recalls Jeff Barnard, president of  Universal Pasteurization Co.. “It just made sense to offer HPP as a value-added service.” With a new owner's capital support, Universal built a second location in the Atlanta area and, in February, acquired DL Foods, in the Dallas-Fort Worth area. Universal now operates nine HPP presses.

Blown seals were a frequent occurrence in the technology’s early days in food. Today’s machines are more industrially hardened and have higher capacities than systems of a decade ago. They also are bigger, weighing up to 80 tons.

Easier loading and unloading is driving down labor costs and increasing throughput, adds Hiperbaric’s Nicolas-Correa. His newest machine, the 525-L, can process about 8,000 lbs. an hour at a cost of less than 4 cents a lb., “and half of that is the depreciation of the machine,” he explains. “A few years ago, with our 300-L system, the cost was over 7 cents a lb.”

Canadian public health officials studied the efficacy of HPP in the wake of the 2008 Listeriosis outbreak that killed 22 and was linked to slicing machines in Maple Leaf Foods’ Toronto RTE plant. The company recalled 220 products and established a $25 million compensation fund for victims. Coincidentally, Maple Leaf was pressure treating meat on one of the plant’s lines but would have needed 10 presses to treat all products. Since then, dozens of HPP systems have been installed throughout Canada.

“Brand protection against pathogens led one sandwich chain to require HPP for its sliced meats,” says Barnard, because a reduced-sodium initiative raised risk levels. “It is a great brand-protection tool.” A Universal-commissioned study in late 2012 projected annual HPP volume growth of 25 percent over the next eight years, and that estimate is proving conservative, he adds.

High-performance elbow grease

The profit margins of some RTE products don’t justify the cost and logistical issues of HPP. Fortunately, improvements in equipment hygienic design and the availability of better methods of sanitation can help processors minimize risk.

Cleanability of equipment was an afterthought for machine builders in the previous century. That began to change when a task force of manufacturers and suppliers in 2003 created the American Meat Institute’s 10 Principles of sanitary equipment design. Recently updated and cross referenced to NSF and AMI standards, those principles — cleanable to a microbiological level, validated cleaning and sanitizing protocols, no niches or collection areas, accessible for cleaning and inspection, etc. — have been embraced by other industry segments.

Cleanability in a fresh or RTE meat plant implies the ability to withstand high-pressure washdown and caustic chemicals. Packaging and conveying specialist Heat and Control Inc. is closely associated with vertical form/fill/seal systems for snack foods, but the Hayward, Calif., supplier has been upgrading and waterproofing components such as Ishida weigh scales, which carry sophisticated electronic controls. An IP69K rating has been secured for several of the weighers, helping Heat and Control secure contracts with USDA-inspected facilities such as Choice Canning Co., which processes RTE shrimp.

Cleanability must be coupled with effective sanitation and disinfection practices, but every processor has to devise a program to address a facility’s specific challenges. Economics is part of the calculation, allows Cristil Garrison, director of training & development at Remco Products Corp., Zionsville, Ind., along with the capabilities of the sanitation crew.

“Drains are one of the biggest challenges when dealing with Listeria,” Garrison observes, and most processors must deal with existing infrastructure that can complicate the solution. In older buildings, the drain in one processing area typically is connected to drains in other zones, raising the likelihood of cross contamination.

“It is an evaluation process,” she adds. “Companies need to analyze what they are trying to mitigate and then choose the tool that helps them best accomplish it.”

Vikan Ceiling Squeegee

Condensation on ceilings and other overhead structures can be a food-safety red flag and a cleaning challenge, which is why Vikan AS developed a specialized squeegee with a built-in catch basin to prevent cross contamination when cleaning.

To help in the process, Remco’s Danish partner, Vikan, created the Hygienic Zone Planner, an iPad app for mapping and color-coding process areas, their equipment lists and the cleaning tools assigned to them. The objective is to help food companies maintain HACCP compliance and generate documentation for auditors and inspectors.

Color coding and dedicated cleaning tools are gaining acceptance worldwide to control pathogens and allergens, Garrison notes, but those tactics need to be paired with the right tool for the job. Bristles on a drain brush need to be long enough for hard-to-reach places but not so long that they will create an aerosol effect that sends germs airborne, for example.

Remco and Vikan have engineered specialty brushes without crevices for bacterial harborhage to accomplish that. Another innovation is a specialized squeegee that collects condensation on ceilings and other overhead structures. The water is retained in the handle, preventing cross contamination and providing a sample for microbiological testing.

Over and above the minimum

As many as 450 shipping containers of IQF shrimp are shipped annually from India to Choice Canning, the Jersey City, N.J., subsidiary of Choice Trading. Some of the shrimp is bagged raw, but an increasing proportion ends up in meal kits with various sauces, vegetables and starch. “Initially, we were treated as a raw product,” even when sold as ready to cook, says Nithin Poulos, junior vice president of operations.

When chicken became a protein option in the meal kits, sales took off. To meet demand, Choice leased 3,000 sq. ft. inside CFC Logistics’ Quakerstown, Pa., cold storage facility. “We were a completely manual process at first, doing only 800 cases a day,” recalls Poulos, a third-generation member of Choice Trading’s owners.

The throughput proved inadequate to satisfy demand, and a fully automated material handling and packaging system came on line in February 2013. Fastback horizontal-motion conveyors deliver the meal components to a waterproof blend-weigher for precise metering and delivery to a f/f/s machine and then through quality-control checks, all part of an integrated system engineered by Heat and Control.

The commissioning came none too soon: sales almost doubled in 2013, and Poulose anticipates another doubling this year. “We’re now doing 2,400 cases a shift,” he says.

From his perspective, the product is low risk: Since the components are in-fed in a frozen state, splattered food is not an issue, and microbiological issues are dealt with before the shrimp is exported. Nonetheless, the line is washed, foamed and subjected to high-pressure washdown after each shift. Although USDA doesn’t require it, swab tests are taken, mostly as a safeguard against allergen residues.

Whether testing for allergens or pathogens, rapid results from swabs are a priority, with reliability and sensitivity givens. Affordability also is an issue, and two scientists and entrepreneurs have developed a series of flow-based tests that match molecular diagnostics but don’t require expensive lab equipment and extensive sample preparation, according to Ben Pascal, chief business officer of Invisible Sentinel Inc., Philadelphia.

The firm recently received certification from the Assn. of Analytical Communities for its third rapid-diagnostic test. Earlier AOAC certifications covered a campylobacter assay and a Listeria monocytegnes assay, but those tests are run on finished goods.

“The challenge in food & beverage is environmental sampling,” Pascal believes, and the latest assay detects the Listeria species, making swabs of contact surfaces practical. A positive result within 24 hours would trigger sampling of finished goods.

The firm also collaborated with Jackson Family Wines of Sonoma on a rapid molecular diagnostic for the Brettanomyces yeast, which is associated with a whiff of barnyard in wines.

Testing is a good defense, but offense wins the game, and RTE processors long have relied on sodium lactate, sodium diacetate and nitrate to control Listeria. Those additives carry baggage in a time of ascendancy for clean labels. Fermentation-based ingredients can deliver the same antimicrobial effect and still support “made with natural ingredients” or “no artificial preservatives” claims, says Simone Bouman, director of business development-meat & culinary at Corbion Purac, Lenexa, Kan.

Corn sugar and vinegar are used to create organic acids during fermentation of Corbion’s Listeria inhibitor called Verdad N16, which the firm debuted at January’s International Production & Processing Expo in Atlanta. The formulation controls Listeria growth for up to 120 days in cured meats, Bouman adds. “The market is continuously looking for a clean label solution,” she says, and a 1.5-2.5 percent concentration of the ingredient typically will produce desirable results, depending on the product’s sodium level, pH and other factors.

Active packaging is another long-discussed RTE safeguard. For some packaging suppliers, pursuit of packaging that delivers an antimicrobial punch resembles a Grail-like quest. Chemists at the food care division of Sealed Air Corp., Duncan, S.C., have researched the effectiveness of adding an antimicrobial to the surface of film.

“To this point, we have not found a solution that meets our criteria and could be taken to the market,” says Mike Rosinski, marketing director of smoked & processed meats.

“We continue to look at it,” Rosinski continues, but additives are effective and less expensive, and the film additive would have to be disclosed on the label. “Microbiologists developed solutions we’ve tested in a Petri dish, but when we use them in practice, the performance is significantly different and not as effective,” he says.

Tried and true thermal treatments that deliver verifiable kill rates will be the food-safety weapons of choice for decades to come, and if Listeria defense was the only issue, there would be no need for new technologies. But flavor considerations, appearance and other factors also influence purchases.

High-temperature steam and infrared tunnels are technologies film suppliers are trying to support, though those processes can generate temperatures that exceed the limits for the clean resins that meet food-law criteria.

HPP is particularly effective for sliced meats and their exposed surfaces, and Rosinski says Sealed Air research into films that won’t crack or develop pinholes began in the 1980s. About 15 percent compression of meat occurs during the process, he points out, and the film must have sufficient elasticity to withstand the compression and subsequent return to its original shape.

High pressure was used in many industries before it was applied commercially to food. Likewise, advancements in molecular science, chemistry and engineering are bringing new tools to the RTE market. There may not be a silver bullet, but there’s an impressive arsenal.