Food safety technology is rapidly advancing year by year, and many companies are using high pressure processing (HPP) and pasteurization for their products’ packaging.
Using HPP and pasteurization for food safety
HPP is a cold pasteurization technique by which products, already sealed in their final packaging, are introduced into a vessel and subjected to high pressure (300–600MPa/43,500-87,000psi) transmitted by cold water, explains Roberto Peregrina, chief scientific technologist, Hiperbaric, Doral, FL.
“Pressure levels above 400 MPa / 58,000 psi at cold or ambient temperature (40-75 °F) inactivate the vegetative flora (bacteria, virus, yeasts, molds and parasites) present in food, extending product shelf life and guaranteeing food safety,” he states. “High Pressure Processing enables the sensorial and nutritional properties of food, due to the absence of heat treatment, and maintains freshness of foods throughout their shelf-life.”
Tom Egan, staff, Cold Pressure Council, Herndon, VA, says that HPP is a strong, proven solution for food safety needs in numerous food and beverage products.
“Using pressure, not heat, HPP inactivates a variety of pathogens in food and beverages while maintaining nutrition and taste profiles of the original product. Another advantage of using HPP is that HPP advances clean-label objectives of the producers of the product,” he notes.
Dr. Errol Raghubeer, senior vice president, HPP science & technology, JBTAvure, Erlanger, KY, explains that HPP is an antimicrobial pasteurization process.
“In food application, it was first reported by Hite (1899) that high pressure reduced bacterial levels in milk by 5 to 6 logs and later, in 1924, Cruess proposed that high pressure can be used to preserve fruit juices. It took several decades for the technology to be implemented commercially with fruit preserves/jams in Japan in the mid 1990’s,” he remarks.
Following an outbreak of E. coli O157:H7 food poisoning in apple juice in 1996, the FDA proposed that all apple juice products be pasteurized with heat, Raghubeer reminisces.
“However, in the late 1990’s, results of tests we conducted using high pressure processing (HPP) in both apple and orange juice showed that HPP was an effective process that would ensure the safety of fruit juices without the damage to nutrients and flavor caused by heat. With the FDA Juice HACCP Rule in 2004, HPP was recognized as a pasteurization process that satisfied the 5-Log reduction rule of pertinent pathogens in fruit juices.”
Similarly, HPP is recognized by the FDA as a decontamination process for Vibrio bacteria in raw oysters, he says.
“In 2003, the FSIS recognized HPP as a post-lethality treatment for the control of Listeria monocytogenes in RTE meat. Similarly, HPP is recognized as a pasteurization process to ensure food safety by Health Canada, the European Commission and other regulatory agencies,” Raghubeer adds.
HPP technology is now used globally in several food and beverage categories to eliminate pathogens, extend shelf-life, recondition contaminated foods, and for other functional processes, he says.
“In its current commercial usage, HPP is not effective against bacterial spores and thus, intrinsic factors of foods and beverages as well as distribution conditions must be adjusted to eliminate food safety hazards with growth of bacterial spores.”
Tom Woodward, CCO, Universal Pure, Lincoln, NE, says that food and beverage brands and manufacturers realize multiple food safety benefits from HPP.
“HPP effectively eliminates foodborne pathogens, bacteria, and mold without harming the nutritional qualities of the product,” he notes.
Increasingly, consumers are seeking products that have a minimum number of ingredients and that are preservative/chemical-free, Woodward says.
“Incorporating HPP into the production process allows brands the opportunity to offer high quality and healthy products that not only maintain the nutritional profile of their ingredients, but can eliminate the need for added and sometimes harmful preservatives. Further, beverage brands and manufacturers can achieve a greater geographic/ and distribution reach with the extended shelf life provided by HPP technology. Additionally, a longer shelf life means less waste and more sustainability.”
Lisa Mitchell, marketing manager, Radio Frequency Co., Millis, MA, suggests pasteurization for foods with dry ingredients.
“For dry ingredients, once thought safe from Salmonella and other pathogens because of the low availability of water, low-moisture foods/ingredients can be effectively pasteurized with RF heating at temperatures lower than typical convection heating because RF is a volumetric heating process,” says Lisa Mitchell, marketing manager, Radio Frequency Co., Millis, MA.
“High temperatures, over-heating the outer layers to get the center mass up to the pasteurization temperature, is not needed as RF heats the entire volume of product at the same time. Typically RF achieves a 5Log reduction at temperatures around 185 degrees Fahrenheit, thus preserving the quality of the product,” she explains.
According to Mitchell, key benefits for using RF Pasteurization for dry ingredients include:
- Volumetric Heating means there is no temperature differential from the surface to center, and no prolonged soak time which could be damaging to protein functionality.
- A Short Heating Cycle allows the product to maintain protein functionality, and other organoleptic and nutritional qualities.
- A Rapid Temperature Rise reduces the ability for microbes to acclimate themselves to defend against high temperatures.
New developments
Woodward says that the most important advancement in HPP technology is its availability to multiple food applications and brands of all sizes.
“Investments in HPP technology from companies like Universal Pure provide the outsourcing of this technology, and allow food manufacturers access to the benefits of HPP without requiring a large capital investment,” he notes.
“Quick turnaround of product, expertise in operating HPP equipment, strict quality assurance processes, and strategically placed facilities throughout the United States allow Universal Pure to support brands of all sizes who wish to benefit from this exceptional technology.”
Last year, Radio Frequency introduced its heat retention zone to their line of pasteurization equipment, says Mitchell.
“The heat retention zone provides the hold time requirement once the RF achieves the pasteurization temperature. This is critical for bulk processing, as material will start to cool once exiting the RF. Pasteurization processes, including RF, are a combination of time and temperature. In bag processing typically we see that the heat can be maintained for the hold time in the bag.”
Raghubeer says that there have been significant developments in HPP equipment over the past decade.
“In the late 1990’s, the only equipment were vertical HPP units with a vessel capacity of 215-L. ACB Pressure System - Alstrom in France introduced the first commercial horizontal system. Currently, this horizontal design with maximum operating pressure of 6,000 bars (87,000 psi) is largely used in all commercial applications except for vertical systems that AVURE offers to segments of the seafood industry,” he comments.
“The improvements in reliability, product throughput with larger vessel size and better/faster pumping systems, and the overall cost reduction have been instrumental in greater industry adoption of HPP. This growth in commercial adoption is also driven by the demand from consumers for healthier, preservative free foods as well as food producers expanding into different product categories.”
Egan says that HPP has been a proven solution for decades.
“Constant, incremental, improvements in throughput, range of applications, handling of the package, and performance are occurring as installations expand. In addition, new machine designs combined with handling technology are generating explosive throughput improvements,” he says.
In addition to operations improvements, The Cold Pressure Council introduced the HPC® mark to assist consumers to identify products using HPP to deliver these benefits, Egan notes. At www.highpressurecertified.org, consumers can learn more about HPP as well as check products that carry the HPC mark.
Peregrina says that one of the biggest advancements in HPP technology is in-bulk HPP, pioneered by Hiperbaric.
“In the traditional in-pack HPP process, beverages are placed in baskets in their final packaging and put into a high-pressure chamber and pressurized to inactivate bacteria, viruses, molds and parasites. However, by processing liquids in bulk, twice as much product per batch can be handled, and then bottled in any format, from cans to glass bottles,” he notes.
In the in-bulk process, beverages are sent to an inlet tank, which contains a recyclable plastic “bladder” occupying 90 percent of the total vessel volume. After that, the beverage is unloaded into an ultraclean Extended Shelf Life (ESL) tank and goes to an ESL filling line, where it can be bottled in any type of packaging material, Peregrina explains.
“Since there is no manual handling of bottles or pouches, labor costs are reduced by more than 80 percent. The energy cost per liter of an HPP beverage is also cut by nearly 50 percent, as almost twice the volume of juice is processed per cycle, while replacement parts costs per liter are reduced by more than 30 percent.”
The Hiperbaric Bulk machine includes several patent-pending innovations, and is the result of a four-year R&D project involving highly-qualified engineering and food processing teams, Peregrina says.
Using HPP in food and beverages
“HPP can be used in a wide range of products, including juices and beverages, avocado products such as guacamole, deli meats, seafood, ready-to-eat meals, dips, spreads, salsas, wet salads, sandwich fillings, baby food, dairy, and pet food,” says Peregrina.
Egan says that the range of consumer products is constantly expanding.
“Beverages plus fruit/vegetable products lead the application use of HPP. The variety of foods include deli meat, guacamole, salsa, dips; seafood, even seaweed, are some strong examples of HPP in daily use,” he explains.
Raghubeer says that many foods are suitable for HPP, with the most critical factor being the presence of free water (water activity/Aw).
“Free water is needed for the disruption of the microorganism’s biochemical functions that leads to cell inactivation. Foods with suitable Aw levels include salsas, dips such as hummus and guacamole. Wet salads, salad dressings, sauce, and fruit-vegetable baby foods are commonly done with HPP where preservatives are eliminated without compromising product safety and shelf-life,” he notes.
Ready to eat (RTE) deli meat is a huge segment of HPP products in the market and there is a global growth in HPP refrigerated-ready meals that offers customers the convenience of healthy home-cooked meals without the kitchen work, Raghubeer adds.
“The seafood industry uses HPP to improve processing such as shucking of crustaceans and shellfish, increase product yield and control microbial growth,” he says.
HPP can be used for all beverages due to the high water activity, Raghubeer remarks.
“There is a vast assortment of fruit juice-based vegetable beverages in the global market that use HPP to meet regulatory food safety requirements without affecting the nutrition and flavor and to extend shelf-life. When pH is lower such as in fruit juice-based beverages, less pressure with shorter treatment times can be used compared to beverages with higher pH such as dairy and nut milks. Dry products are not suitable for HPP due to the lack of free water.”
Woodward reiterates that HPP works well with fresh products such as ready-to-cook (RTC) and ready-to-eat (RTE) meat and poultry products, guacamole, salsas, dips, wet salads, premium juices and other beverages.
“HPP will continue to experience growth across multiple categories, to include applications like baby food, soup and pet food products. With the industry’s continued realization of the many benefits of this technology, it will surely have a positive and growing impact in the food and beverage space as a whole,” he remarks.
Mitchell says that the target customers for HPP are those that manufacture/sell/use dry ingredients like flours, seeds, and spices.
“The low moisture/low water activity foods and ingredients that are either sold directly to a customer that wants or needs a low-microbe count material, or a manufacturer whose manufacturing process doesn’t include a kill step—maybe sesame seeds applied to a bun after baking, or protein mixes,” she elaborates.
What’s next
“The food and beverage industry will undoubtedly expand and evolve with innovative introductions,” Woodward predicts.
“Consumer requirements for safe, healthy, and preservative-free products that they can trust will surely continue to grow. HPP is perfectly aligned with the food and beverage industry to support their needs to provide these safe, preservative free, and long shelf life premium products.”
Raghubeer says that although little is published in the application of HPP in the medical and pharmaceutical industries, there continues to be very active research in these areas.
“We are actively pursuing funding and partnership to investigate the development of a safe and effective COVID-19 vaccine. HPP can be used to inactivate the SARS-CoV-2 virus instead of heat and chemicals, where the whole inactivated viral (WIV) particles can be used for vaccine development. In the future, HPP may also provide the opportunity to develop nutraceutical food and beverages targeting specific medical treatments.”
Egan says that [there will be] more performance improvements and more products using HPP.
“CPC members are actively working on extending solutions into baby food, coconut water, CBD, and other areas. The machine manufacturers are delivering improvements to streamline product infeed, and packaging handling on discharge. Stay tuned.”
Peregrina says that the growth categories for HPP include premium juices, smoothies and fruit-based waters, like coconut and watermelon water.
“We also see growth in ready-to-drink beverages like cold soups, cold-brew coffees, and teas. The functional beverage category, including wellness shots and CBD-infused beverages, also is experiencing growth. Additionally, pet food, new guacamole products, salsas, ready-to-eat foods and plant-based foods also benefit from HPP.”
HPP adoption continues to rise with a CAGR of around 6-7 percent projected for the 2020-2025 period, he says.
“With consumer demand for fresh-tasting food and beverages with no preservatives and healthy, natural ingredients, HPP sales will continue to grow.”
