Pascalization fills the bill and extends shelf life, Under Pressure to Improve Fresh Food Safety |

Pascalization fills the bill and extends shelf life, Under Pressure to Improve Fresh Food Safety

Jeri L. Dobrowski
Courtesy photoThe black cylinders (left) in this 350-liter, horizontal High Pressure Processing system shuttle prepackaged food items into the pressure chamber (behind enclosure). As with traditional pressure canning, different foods require different pressure settings and processing times. However, HPP is many times greater and does not require heat. (Photo courtesy of Avure Technologies).
Hans Nordlander |
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Despite advances in science and technology, food safety continues to make headlines, too often for the wrong reasons. Pascalization, or High Pressure Processing (HPP), may change that.

Pioneered by 17th century French scientist Blaise Pascal, pascalization utilizes high pressure to eliminate naturally-occurring microorganisms. Unlike pasteurization, it is a non-thermal process. And, unlike irradiation, consumers aren’t averse to the technology.

In the late 1800s, West Virginia Agricultural Experiment Station professor Burt Hite, had some success in preventing milk from spoiling by using high pressure. However, he was stymied by ongoing equipment failures. Small wonder, today’s torpedo-shaped pressure chambers are built to withstand 87,000 pounds per square inch for upwards of 15 minutes. The force disrupts cellular functions, disabling such formidable food safety villains as E. coli O157:H7, Listeria monocytogenes, Salmonella, Campylobacter, many yeasts, molds, and most viruses.

While the United States Department of Agriculture (USDA) and Food and Drug Administration (FDA) approved process is tough on pathogens, it’s easy on food.

Typically there is no change in appearance, flavor, texture, or nutrition. A whole grape submitted to the pressure – equal to three 5-ton elephants balanced on a dime – is unaffected.

Research at Technologico de Monterrey, Mexico, shows HPP improved the carotenoid levels of avocado and papaya pulp by more than 50 percent. Some individual antioxidants increased by up to 513 percent.

Other studies show orange juice retains more vitamins with HPP than pasteurization. Sliced roast beef maintained its color, texture, and taste for more than 100 days, as compared to less than 40 days for conventional packaging.

Such results, along with other benefits, make HPP attractive: microorganisms killed on both food and package at the same time; an extended refrigerated shelf life – more than double in most instances; sustained quality over shelf life; reduced spoilage and returns; increased distribution opportunities; and reduction or elimination of chemical preservatives, including salt.

Jams, jellies, sauces, dips, ready-to-eat meats, cheese, oysters, seafood, fruits, and juices are most frequently processed via HPP. Liquids are processed in bulk, then aseptically packaged. Food items are batch-processed after packaging. Most vacuum and gas-flushed cups, bags, and pouches are suitable for pressurization. Items are loaded into a chamber to which water is added; then pressure is applied. The water acts as the pressure transfer medium. Since no chemicals are involved, organic and all-natural products retain their label.

Avure Technologies is the world’s largest manufacturer of HPP equipment. Better known for their ultra-hydrostatic presses that yield metal alloys for jet engines and knee replacements, and for producing industrial-grade diamonds. Avure is developing equipment for an expanding food processing market. It is estimated that HPP is used to process $3 billion in food products annually.

Jerry Toops, Avure Technologies Business Unit Director, says pressure technology has exploded in the last five years. “Initially the interest was in food safety, but now it’s being driven by product development that is possible because of the technology.”

Toops credits Texas restaurateur Don Bowden with introducing HPP to the U.S. food industry. In the 1990s, after researching and brainstorming ways to increase the shelf life of his renowned guacamole, Bowden asked Avure Technologies to process a batch of guacamole in one of their industrial presses. That test involved less than a pound of product, but it was enough. The shelf life of Bowden’s Wholly Guacamole was extended from three days to 30 days. Today, his Fresherized Foods is the world’s largest producer of high-pressure processed foods, which they call Hgh Pressure Pasteurization.

Starbucks also uses the term High Pressure Pasteurization. The coffee giant recently purchased super-premium juice manufacturer Evolution Fresh. Their juices have a 45-day shelf life.

Hormel calls it true taste technology. Their bread ready and natural choice sliced deli meats are promoted as “made with fewer chemical additives for better, more true beef taste.”

HPP holds great promise in the meat industry, where added benefits include marination and tenderization of packaged cuts. In February 2011, Cargill announced they had perfected “an existing food processing technology to create Fressure™ fresh ground beef patties, which have double the shelf life of traditional fresh burgers, benefit from enhanced food safety while also providing optimal flavor and a consistent high-quality eating experience for consumers.” Produced at the Columbus, NE, facility and processed by a third-party provider, Fressure™ patties have a 42-day shelf life.

The American Pasteurization Company (APC), Milwaukee, WI, is the first U.S. company to offer HPP on a commercial tolling basis. Noting that recent advances in pressure equipment having significantly lowered the cost of use, APC exists solely to process prepackaged food items for other companies.

At the opposite end of the spectrum, Goose Point Oysters in Washington State operates a small-scale HPP unit, processing molluscs at 43,000 pounds of pressure for 90 seconds. Besides taking the risk out of eating raw oysters, it extends the shelf life to 17 days.

Along with inactivating bacterial pathogens such as Vibrio, coliform bacteria, and viruses, seafood processors see an increase in meat recovery of as much as 50 percent over traditional cooking, along with improved product weights of as much as 10 percent from the natural hydration of proteins. HPP shucking of shellfish and crustaceans allows for a huge reduction in labor costs, with meat releasing cleanly without knife damage.

The future is bright for pascalization. Indeed, Popular Mechanics included HPP in the Jan. 3, 2012 issue under “10 Tech Concepts You Need to Know for 2012.” It is not, however, without limitations. Cylinder capacities in the largest commercial meat units max out at 350 liters or about 92 gallons. The largest seafood applications, operating at a lower psi, are 687 liters.

Entry-level units with a 35-liter capacity start at $750,000; 100-liter setups, $1.2 million; 350-liter presses, around $2.3 million. By virtue of the small processing lots, additional handling, and costs, HPP products necessarily command a premium.

Still, a technology that inactivates food-borne illnesses, preserves flavors and nutrition, and extends shelf life-without chemicals, preservatives or heat-is certain to attract attention among food processors and consumers. That makes for good headlines.

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