CHICAGO — Cold-pressed juices — those often pricey refrigerated fruit and vegetable extractions that went mainstream about five years ago — initiated the growing popularity of high-pressure processing (H.P.P.) in the beverage category. Also known as pascalization, H.P.P. is a non-thermal form of pasteurization with the ability to destroy pathogenic and spoilage microorganisms.

The H.P.P. system involves the loading of hermetically-sealed packages into carrier baskets. These baskets are inserted into a vessel that gets sealed by plugs. Potable water is pumped into the vessel, creating isostatic pressure on the packages, which remain at the high pressure for about six minutes, with pressures and times varying by product. The pressure is transmitted uniformly throughout the packaged food, regardless of its composition, with the pressure disrupting microbial biochemistry, including autolytic enzymes. This destruction helps preserve freshness and increase shelf life.

The H.P.P. technology became popular with cold-pressed juices because it provides a non-thermal food safety kill step, extending a cold-pressed juice’s unopened refrigerated shelf life from a week to about 30 days. Cold-pressed juices, as the name suggests, are all about being manufactured without heat. The juices are extracted using a slow pulverizer with hydraulic press, as compared to traditional centrifugal juicing processes that generate heat. This is done in order to preserve more of the nutrients and active compounds in the whole fruits and vegetables.

If a manufacturer is going to use this more intensive juicing process, heat pasteurization for shelf life extension is not an option. That’s what makes H.P.P. attractive.

The H.P.P. opportunity

U.S. food and beverage manufacturers have had H.P.P. technology commercially available for more than 15 years, but it’s only been about a decade since shoppers learned of it with the introduction of packaged guacamole. Since, its use has been gaining momentum around the world. The challenge for many — in particular start-ups with small production runs — is that the system requires a large capital investment. But that’s where co-packers may assist.

More than 200 industrial-scale H.P.P. machines are in service in the United States, with most owned by food and beverage companies that primarily use them for their own products. The nature of the technology, for the most part, allows the same H.P.P. system to process many varied foods and formats, which is why some of these companies, as well as companies that do not sell any of their own product, operate as a “toller.” This is an industry term referring to a company that will H.P.P. process foods and beverages on a fee-for-service arrangement, and it is a large, and growing part of the H.P.P. market.

Tio Gazpacho“Although thermal pasteurization remains a core technology in the food and beverage industry, it may affect the appearance, flavor and nutritional value of foods, and does not necessarily meet the demand of modern society for natural, fresh and aesthetically appealing foods,” according to Global Trends-Food & Beverage Processing Report 2018 from The Association for Packaging and Processing Technologies (P.M.M.I.), Reston, Va.

Lu Ann Williams, director of innovation, Innovation Market Insights, The Netherlands, said H.P.P. is considered to be a fresh alternative to preservatives and complements the on-going clean label processing trend.

It’s no wonder that in the past year or two, H.P.P. has expanded beyond cold-pressed juices and now is used on everything from cold-brew coffee lattes to probiotic shots. It is recognized as a natural and environmentally friendly technology that eliminates the need for preservatives and other shelf life extending additives.

Fresh fuels H.P.P. growth

As demand for fresh, minimally processed foods and beverages grows, more retailers are stocking their shelves with products made using H.P.P. in order to help ensure food safety, food quality and to eliminate food waste, according to a survey from Universal Pure, Villa Rica, Ga.

Eighty-five per cent of retailers said their companies are affected by the fresh food demand, and 78% went so far as to say they’re favoring companies that produce fresh product options, the survey found. Demand is so high that more than 60% of retailers said they’re stocking more refrigerated and fresh products, while 48% said they’re expanding their refrigerated section. That’s where H.P.P. beverages are merchandised.

A growing number of producers and retailers are more familiar with H.P.P. than ever before, from 60% in 2016’s survey to 77% (producers) and 74% (retailers) in 2017. Seventy-eight per cent of retailers said they have a favorable view of H.P.P., with 85% indicating that the method of processing used by a producer affects their decision to stock a product.

“The survey results demonstrate that H.P.P. is a preferred technology for food safety, food quality and shelf life,” said Mark Duffy, chief executive officer of Universal Pure. “Consumers want better-for-you foods that are fresh, tasty, preservative-free and safe, and H.P.P. can help deliver these results.”

Ripe Craft juicesThe survey measured and compared perceived advantages in food quality, food safety and food waste with other types of pasteurization, including heat pasteurization, pulsed electric field radiation, ultraviolet radiation and other processes. The H.P.P. approach was favored by producers and retailers on measures concerning food quality (67%), food safety (59%) and food waste (56%).

The biggest reason producers said they use H.P.P. is for shelf life extension (74%), with longer shelf life translating to reduced food waste due to expired or spoiled product. Ninety-six per cent of retailers said they are more likely to purchase a product with a longer shelf life, while 94% of producers indicated they could expand distribution range if their products had a longer shelf life.

Advantages beyond shelf life

Extending shelf life, safely, may be the No. 1 reason for switching from thermal processing to H.P.P., but there are additional benefits. With H.P.P., a beverage receives the pressurizing treatment evenly. In thermal processing of beverages — especially those with pulp or that are highly viscous — uneven heating may require extra heating to ensure an effective kill step. This may take a toll on beverage quality and nutritional integrity.

Thus, another advantage is that the pressure does not impact the nutritional profile of the product. Vitamins, minerals, nutrients and food enzymes — proteins that assist the consumer with digestive and metabolic function — remain intact. Flavor, color and texture also are unaffected by pressure.

Also appealing is the fact that pressurizing takes place in the sealed retail container. This renders the product immediately ready for distribution.

Beverages that are sensitive to heat processing, and with a pH of less than 4.6, are the best candidates for H.P.P. Low-acid beverages are possible; however, a second hurdle may be needed depending on specific food safety risks.

Evolution Fresh kombuchaThe H.P.P. technology does not render a beverage shelf stable. These are perishable beverages; however, the non-thermal process allows for an extended refrigerated shelf life until opened. This is because H.P.P. is not effective on spoilage bacterial spores.

It also is considered a “log reduction” technology, which means the higher the pressure and longer the hold time, the greater the reduction of microorganisms. By understanding the bacteria load, H.P.P. processers can select the best parameters to achieve their food safety and shelf life goals without significantly affecting other product attributes, such as the presence of beneficial bacteria in the product. Pressure and hold time adjustments may be necessary to ensure viability of probiotic cultures.

In general, higher-acid products require lower pressure and hold times than lower-acid products to achieve the same desired extended shelf life. And, for the most part, beverage formulations require little or no adjustments when switching from thermal processing to H.P.P., as the non-thermal technology does not impact the performance of acidulants, proteins or sweeteners.

For manufacturers of fruit, vegetable and coconut water juice beverages, it is important to adjust the pH to ≤4.6 to be in compliance with the U.S. Food and Drug Administration’s 5-log pathogen reduction rule as identified in Juice Hazard Analysis and Critical Control Point Program. In addition to pH, the Brix level is important when selecting H.P.P. treatment conditions, as higher Brix will affect product water activity, which in turn influences microorganism survival.

There are limitations, mostly in package selection. For starters, the package must be hermetically sealed. For maximum shelf life, packaging with barrier properties often is selected. This includes using films with low oxygen transmission rates and low moisture vapor transmission rates. These films are used to form all shapes and sizes of plastic bottles and cups, as well as pouches, with or without spouts.

Bottling juicesWith the first-generation H.P.P. systems currently in the market, an important package attribute is for at least one surface to be able to accommodate the temporary volume change that occurs during the H.P.P. cycle. When isostatic pressure is applied, any headspace within the package is compressed and then the product is compressed. As the pressure is released, the product and headspace return to pre-H.P.P. volumes, which is one reason why plastic has long been the preferred container. While paper packaging is flexible, it is not recommended because of the exposure to water during submersion in the H.P.P. vessel.

Second-generation H.P.P. systems are in development that allow for the use of other materials, namely glass, metal and paper. These systems are a two-step process. The beverage undergoes H.P.P. in a hermetically-sealed bag. After undergoing sufficient pressure and hold time to destroy all foodborne pathogens, the vessel is depressurized as usual. Then the bag is connected to an aseptic filling line, allowing processors to use any type of packaging.

Food and beverage manufacturers using H.P.P. technology are not required to label or declare use on packaging or elsewhere. The Cold Pressure Council (C.P.C.), which was convened by the P.M.M.I. in early 2017, believes that it makes sense to communicate use to consumers so they better understand why certain products have a long shelf life without the inclusion of preservatives. To assist with this effort, the C.P.C. now offers a “High Pressure Certified” seal through a third-party audit program for certification.