The theory has been around for more than 100 years: the concept of killing foodborne pathogens by subjecting fresh foods to extreme high-pressure that leaves the taste and texture of the product but kills the bugs. Now, Flow International Corporation (www.flowcorp.com) has developed a commercially viable food processing technology based on this theory that destroys such harmful pathogens as E. coli O157:H7 bacteria without the use of heat, extreme cold, chemicals or irradiation. They process the food at ultra high pressure.

Known appropriately as Ultrahigh-pressure (UHP) fluid technology, Flow International’s system works by exposing pumpable product to pressures ranging from 50,000 to 100,000 psi for a relatively short time—usually anywhere from 30 to 180 seconds. According to the developers, exposing foods to this high pressure destroys spoilage microorganisms as well as harmful pathogens. Depending upon the pressure and the time used, other benefits can include enzyme inactivation and the denaturing of proteins.

“The result of this technology,” boasts Flow International’s Rick Marshall, vice president of corporate market and application development, “is not only safer food, but fresher, better-tasting food that is just as good as the day it was packaged.”

Flow International’s UHP food production line utilizes a device called an isolator, into which the food is pumped, then pressurized, by automated computer control. After being held for a short period the food then is discharged into a filling station for packaging or bottling.

To date, the UHP vessel system developed by Flow International has been applied in such food product areas as fruit juices, vegetable purees and meats, and on fresh oysters—notorious carriers of the potentially deadly Vibrio vulnificus bacteria. And in the latter case the oysters are also, as a consequence, shucked by the high-pressure processing.