« December 2006 Table of Contents
High-pressure processing makes seafood safer
HPP technology can be an effective marketing tool if
you learn what it's all about
By Steven Hedlund
December 01, 2006
Burt Hite was way ahead of his time. In 1899, the West
Virginia scientist discovered a means to pasteurize milk using
high-pressure processing (HPP).
"The problem was," says Dr. Daniel Holliman, research
coordinator of Virginia Tech's High Pressure Processing
Laboratory in Blacksburg, Va., "the machine kept blowing up on
More than a century later, technology finally caught up with
Hite's vision, and a number of companies worldwide are making
food safer by subjecting it to intense water pressures,
including oysters and American lobster. Foods treated with HPP
didn't reach the commercial marketplace until 1990, when a
Japanese company developed a way to use HPP on jam. By 2004,
about 40 companies, half of them based in the United States,
produced HPP foods, and there are even more today.
However, retailers, foodservice operators and especially
consumers are relatively unfamiliar with HPP. Questions about
the fundamentals of this processing technique are sure to arise
as more products hit the marketplace. Now's the time to enroll
your counter help and waitstaff in High-Pressure Processing
101. The more you teach them about HPP now, the less pressure
they'll feel later.
Q. What does high-pressure processing do?
HPP is the technique of subjecting food to high hydrostatic
pressures of 14,500 to 145,000 pounds per square inch,
depending upon the density of the food. For example, jams and
jellies are subjected to 14,500 to 58,000 psi, while in-shell
oysters are subjected to 30,000 to 50,000 psi. The food is
placed in a chamber and immersed in a pressure-transmitting
liquid, usually water. A pump pressurizes the water, killing
foodborne pathogens such as Vibrio , Listeria , Salmonella and
E. coli and doubling or tripling the product's refrigerated
shelf life, compared to an unprocessed product.
HPP "does not sterilize a product," says Holliman, "but it
eliminates a majority of foodborne pathogens and spoilage
Q. What are the benefits of HPP?
Unlike cooking, HPP raises the food's temperature only
slightly and has little to no effect on its chemical make-up,
so the food maintains its flavor, texture, appearance and
nutritional content. Because no chemicals are removed or added,
processors can market the food as "all natural."
In addition to making food safer, HPP "is a marketing tool,"
Q. Does HPP damage food?
No. Because pressure is applied uniformly, the product
maintains its form and shape.
For example, a grape is easily crushed when squeezed by
hand, because pressure is applied unevenly. But a grape inside
a water-filled plastic bottle remains intact no matter how hard
the bottle is squeezed.
Q. What are the costs
of using HPP?
Initially, HHP machines are expensive, running up to $2
million, Holliman acknowledges. Virginia Tech spent $650,000
17,600-pound machine, Avure Technologies' Quintus QFP
35L-600, in 2003. (Avure is a subsidiary of Flow International
of Kent, Wash.)
But the cost of HPP machines is on the decline, and the
machines are time, labor and energy efficient, so over time
processors save money, says Holliman. It takes just a few
minutes to pressurize a batch of food and just a few
individuals to operate the machine, which requires only
electricity and water.
Q. When did seafood processors begin using HPP?
In the late 1990s, Ernie Voisin, founder of Motivatit
Seafoods in Houma, La., with the help of Flow, began using
hydrostatic pressure to purge Gulf oysters of Vibrio vulnificus
and separate the meat from the shell. Motivatit's HPP oysters
are marketed under the Gold Band brand.
Joey Oysters of Amite, La., and Nisbet Oyster Co. of Bay
Center, Wash., also market HPP oysters, processed using Flow's
Fresher Under Pressure® technology.
Shucks Maine Lobster of Richmond, Maine, sells HPP, fresh,
raw lobster meat, and Clearwater Seafoods of Bedford, Nova
Scotia, markets HPP, frozen, raw lobster meat.
HPP can also be applied to blue crabs. The process "makes it
a whole lot easier to pick the meat out of the shell," says
Shellfish is ideal for HPP because the meat is protected by
the shell and doesn't need to be packaged when processed, as
with other foods.
Holliman isn't aware of any U.S. processors applying HPP to
finfish, but he and his Virginia Tech colleagues are
experimenting with that application.
"The meat has a tendency to look cooked" when subjected to
HPP, he explains. "The temperature isn't elevated all that
much, but the meat looks red or pink. The same happens with
Retailers and foodservice operators must educate consumers
about HPP and its effect on flesh color for HPP finfish to be
marketed successfully, adds Holliman.
Q. What other foods are
manufactured with HPP?
HPP is used to process numerous solids and liquids,
including sliced deli meats, sausages, hot dogs, avocados,
guacamole, salsa, jams, yogurt, fruit juices, apple cider and
applesauce. Perdue and Hormel are among the food companies
Acidic foods with a high water content are ideal for HPP,
Foods with a high air content, such as strawberries, are
not, he notes. Proving the point, Holliman and his colleagues
used their HPP machine to transform a marshmallow into a
marble-sized ball and a Styrofoam coffee cup into a shot
However, strawberries packaged in vacuum-sealed pouches and
subjected to HPP "do just fine," says Holliman; he and his
colleagues are experimenting with the fruit.
Q. Is HPP becoming more
Holliman is confident that the number of U.S. processors
applying HPP to seafood and other foods will only increase, due
to the technology's extensive list of benefits, particularly
"This summer's West Coast Vibrio outbreak probably wouldn't
have occurred," he says, "if those oysters had been subjected