For Chris Staudt, high pressure processing (HPP) is a key that has opened new doors, professionally speaking. As CEO of Chairman’s Foods, LLC, Staudt oversees production of custom fresh and frozen products for food service and retail customers in a 40,000-square-foot plant at the company headquarters in Nashville, Tenn. and a 38,000-square-foot facility in Columbus, Ga.
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“HPP is nothing new,” Staudt says, “but it has opened doors for us, allowed us to provide solutions for our customers that traditional methods would not allow.”
Simply stated, HPP is a technique by which food and beverage products, already sealed in final packaging, are introduced into a cylinder-shaped pressure chamber where they are subjected to a high level of hydrostatic pressures (43,500-87,000 pounds per square inch) transmitted by cold water. The HPP process can take from one to six minutes.
Acknowledged by USDA and FDA as a kill step, HPP is a natural process that inactivates E. coli O157:H7, Salmonella, Listeria monocytogenes, and other foodborne pathogens, with minimal impact on a consumable product’s taste, texture, appearance, or nutritional value.
Tracing its roots to the 17th century, HPP is also called pascalization, as an homage to the French scientist Blaise Pascal (1623-1662) who studied the effects of pressure on fluids; bridgmanization, after physicist Percy Williams Bridgman (1882-1961) who won the 1946 Nobel Prize for Physics for his work on the physics of high pressures; and high hydrostatic pressure, abbreviated as HHP.
In June 1899, Bert Holmes Hite (1866-1921) published a bulletin entitled “The Effect of Pressure in the Preservation of Milk,” which first documents pressure being used as a food preservation method. Hite is credited as the first person to conclusively demonstrate the inactivation of microorganisms using pressure.
Founded in 1976, Chairman’s Foods started using HPP in 2011. Examples of the company’s products include kettle cooked fillings for chicken pot pies; sous vide cooked proteins; ready to eat chicken salad and other prepared items for food service delis and steam tables; and assorted co-pack queso dips for several grocery store chains, including Whole Foods.
Speaking of chicken salad, Staudt is quick to mention that HPP has helped Chairman’s Foods attract new customers to the wildly popular comfort food.
“Many companies make chicken salad, but, thanks to HPP, we can make it using fresh ingredients, with a longer shelf-life, and a clean label with a short list of ingredients void of powders and preservatives,” Staudt explains. “Since we are not stuck with old processing traditions, we have new opportunities.”
Chairman’s Foods utilizes the HPP services of Universal Pure, shipping products to the latter’s facilities in Villa Rica, Ga., Coppell, Texas, and Lincoln, Neb. From those locations, Chairman’s arranges shipping to its customers once HPP is completed.
HPP is typically used to enhance food safety and extend product shelf life, which is the technology’s biggest economic impact, says Mark Fleck, an HPP consultant for Universal Pure. “Because HPP addresses typical spoilage organisms such as bacteria, yeast, and mold, producers realize significant shelf life increases often a two to four times improvement,” he relates. “More times than not, HPP becomes a critical control point in a food producer’s Hazard Analysis and Critical Control Points (HACCP) plan.”
Another benefit, Fleck mentions, is that HPP can also serve as a package leak detector. “HPP uses simple water pressure which is applied uniformly (isostatic) to the packages,” he notes. “If the package integrity is faulty, operators can remove the defective packages post HPP, thereby delivering 100 percent quality packaged products to their customers. Food producers can reduce or eliminate credits and chargeback expenses.”
According to Fleck, the added shelf life benefit of HPP produces savings across the production and distribution spectrum. “Manufactures may be able to produce the product less frequently and in larger batches, thereby making their operation more efficient,” he explains. “Logistics may have the option to ship full truckloads rather than LTL (less than truckload) shipments, thereby obtaining better rates. And, extended shelf life helps retailers reduce stocking frequency and minimizing out of code date products.”
Impact on Food Packaging
“The first and major consideration when selecting packaging for HPP is that the package will be submerged in water during the process,” Fleck says. “Secondly, some flexibility must be a part of the package.”
Fleck notes that these requirements can be addressed by selecting a plastic bottle, bag, stand-up pouch, or utilizing form-fill-seal packaging technology. “Many semi-rigid cups with heat sealed lidding films perform well,” he points out. “And there are a variety of peelable lidding films available to make the package more consumer friendly.”
From a material perspective, there are numerous options to choose from, Fleck says. “For example, PET (polyethylene terephthalate), HDPE (high-density polyethylene), and PP (polypropylene) are excellent choices,” he relates. “If barrier properties are desired, EVOH (ethylene vinyl alcohol) or nylon can become a layer in co-extruded films.”
Label type is another important element of successful HPP, Fleck adds. “Think in terms of non-paper-based labels suitable for food packaging,” he advises. “Don’t forget to take in to account that the label adhesive will also be exposed to moisture. A popular alternative is to print the label directly on the food package or one can apply the label post HPP.”
Grant Lorsung, president of True Fresh HPP, Buena Park, Calif., says the effect of HPP on food packaging has been monumental. “While speaking recently with a large supplier of plastics, they mentioned that just five years ago they were not going to waste time on developing specific resins or packaging offerings for HPP,” he relates. “But HPP is revolutionizing the food packaging industry, and even this particular plastics supplier has since developed a full catalog of films and containers of all sizes and shapes designed specifically for HPP.”
Packaging manufacturers focus on the understanding of design to handle the HPP process, Lorsung mentions. “To that end, special fitments on spouts, welds on edges, and shapes to withstand HPP pressures are being incorporated into HPP packaging,” he says.
Offering HPP services since 2015, True Fresh HPP operates four Hiperbaric 525 processors, with a total annual capacity of 100 million pounds.
The portfolio of food products that True Fresh HPP processes includes hummus, salsas, deli meats, marinated meats, cold-pressed juices, sides, sauces, vegetables, spreads, milk, nut milks, cheese, sausage, cold coffee drinks, baby food, and pet food.
In March 2018, True Fresh HPP launched a partnership with NutriFresh Services, Edison, N.J., an HPP and cold-pressed juice manufacturing facility. By combining True Fresh’s four Hiperbaric HPP machines with NutriFresh’s three Hiperbaric HPP units, the merger creates a state-of-the-art HPP tolling enterprise with a capacity of 200 million pounds annually.
“This is a process that is just in the infancy stages,” Lorsung emphasizes. “As the U.S. consumer begins to realize just how much better it is for food safety and quality, HPP technology will continue to grow at an exponential rate.”
Lorsung adds that HPP technology demonstrates the ability to extend chilled shelf life up to 10 times the normal range.
“Because HPP is a cold process, it does not alter the food product, and no artificial preservatives or additives such as color or flavor are needed,” he relates. “Vitamins and minerals remain intact after HPP, and taste, texture, and appearance all remain the same.”
HPP is currently estimated to be a $12 billion to $15 billion per year retail industry and is growing steadily, according to a 2015 market analysis completed by Visiongain, London, U.K. North America commands close to 60 percent of the global retail HPP market, followed by Europe at 25 percent and Asia at 10 percent. Visiongain expects HPP retail to grow to $20 billion by 2019. By 2023, the HPP market is estimated to reach close to $40 billion and should exceed $50 billion by 2025, based on a 16.5 percent compound annual growth rate (CAGR), Visiongain notes.
The HPP equipment market, projected to grow at a CAGR of 11.26 percent, will reach $500.3 million by 2022, according to Research and Markets.
HPP Validation Center
Cornell University opened the HPP Validation Center at its Geneva, N.Y., campus on Feb. 1, 2017.
According to Randy Worobo, PhD, a professor of food microbiology in Cornell’s Department of Food Science, three types of customized services are offered at the 1,500-square-foot Center: HPP safety validation studies, microbiological shelf-life studies, and physicochemical evaluations. The Center features a 55-liter commercial Hiperbaric HPP unit.
“We do the full range of validation studies for bacterial pathogens and protozoan parasites,” Dr. Worobo relates, noting that, since the Center is designated biosafety level 2, Clostridium botulinum is not tested there. “Our pathogen validation studies are conducted with 5-strain cocktails using isolates that are from similar sources. We can perform HPP pathogen validations and shelf life determinations for a variety of foods that include juices, meats, purees, wet salads, etc. Due to the HPP unit being part of a biosafety level 2 laboratory, no processing for commercial sale is permitted.”
There are two prerequisites for HPP treatment at the Center, Dr. Worobo mentions. “Foods must be packaged in flexible containers that allow the transmission of pressure and can withstand the high pressures without rupturing or leaking,” he says. “And foods should contain minimal amounts of air or dissolved gasses.”
In just over a year, more than 100 pathogen validation studies have been performed at the Center for a whole gambit of products, Dr. Worobo reports. “Many of these products are already commercialized and being sold in the marketplace across the U.S.,” he notes.
Cold Pressure Council
In March 2017, the Cold Pressure Council (CPC) was launched with a mission to lead, facilitate, and promote industry standardization, user education, and consumer awareness of HPP, according to Joyce Longfield, MS, vice president of product innovation for Good Foods Group, LLC, Pleasant Prairie, Wis., and CPC chair.
Managed by PPMI, The Association for Packaging and Processing Technologies, Reston, Va., the CPC was formed by nine founding member companies that contributed time, talent, and financial resources to establish the Council on a firm footing, Longfield says.
“Currently boasting more than 20 members, the CPC includes companies that have and use HPP equipment, such as machinery manufacturers and processors; suppliers of materials associated with HPP, including packaging; and regulatory and academic professionals,” she relates. “Our long-term goal is to be a global organization.” Good Foods and Universal Pure are two of the founding members.
The CPC has developed a High Pressure Certified logo that members can use after their HPP process, HACCP plan, and validation studies are verified by a third-party audit, and after paying the CPC licensing fee of $250 per stock keeping unit per year. Brands that recently started using the logo include Good Foods, Evolution Fresh, and Suja Juice, Longfield notes.
The logo program reflects the goal of the Council, which has always been two-fold, Longfield says. “First, we want to create uniformity among the HPP industry through consistent use of the technology that meets regulatory requirements,” she points out. “To do so, we provide guidance on using HPP as either a CCP or for shelf life extension. This led to creating the logo program for companies that wanted to demonstrate support for consistent validation for use of the technology. The logo program also provides organizations support in bringing awareness to the consumer.”
Second, the Council strives to grow consumer awareness of the benefits of HPP food, and ultimately consumer demand for these food and beverages, Longfield continues. “The website for the logo, expected to be up and running by the end of the summer of 2018, will be separate from that of the Council and will have the look and feel similar to that for non-GMO products, where the information provided is to educate the consumer on HPP benefits,” she says. “The logo website content will not be overly scientific, but rather will be information that’s easier to digest. It will not be a platform to sell either the technology or CPC member companies offering the services for the technology. All of this information would be found on the Council website.”
Tips for Successful HPP Packaging
Mark Fleck, an HPP consultant for Universal Pure, offers the following guidelines to maximize success with HPP technology:
- The package must be hermetically sealed (air tight);
- Many existing package types are compatible with HPP—vacuum packages are ideal;
- Headspace is okay but may increase HPP costs due to basket fill efficiency and slightly increasing cycle times;
- At least one surface must be flexible to accommodate the temporary volumetric change of up to 15% plus any headspace; and
- Check to see if adding barrier properties can better take advantage of the increased shelf life HPP delivers—often decreasing the oxygen transmission rate and moisture vapor transmission rate film specifications can maintain optimal product quality over the extended refrigerated shelf life.—L.L.L.