Two years ago the Meidi-ya Food Factory Corp. in Osaka began selling premium jams, jellies, fruit sauces and yogurts manufactured under the process. Though three times more expensive than conventional heat-sterilized products, the company’s High Pressure’S product line has been a hit. Meidi-ya has increased production from 100,000 cups annually to 1 million. “I don’t mind paying extra money for better taste,” says Ikuko Kawakami, a 28-year-old Tokyo housewife.
What is high-pressure food processing? Basically, it is a method of preserving certain foods by using water pressure instead of heat. (It should not he confused with home pressure cooking, an altogether different process.) In conventional manufacturing of packaged liquid products, food makers typically boil the food in batches to kill bacteria. But in addition to zapping parasites, heat destroys some vitamins and minerals-up to 30 percent, research shows-and slightly alters the taste. According to officials at Meidi-ya and Prof. Rikimaru Hayashi of Kyoto University’s Agricultural Chemistry Department, there is no such trade-off with high-pressure processing. The pressure-far exceeding that found in the deepest parts of the ocean-kills the bacteria but leaves the food’s vitamins and natural flavor virtually unscathed. It also bursts the cell membranes in the fruit, releasing its flavor without pulverizing the chunks.
Daniel Farkas, chairman of the Food Science and Technology Department at Oregon State University, points out that pressure processing has inherent limitations. The biggest is that it works best with foods containing acids, such as fruits. The higher the acid activity level in a food, the more effective pressure processing is. Even so, Farkas says, some popular low-acid food groups-like seafood and meat-can also be effectively pasteurized before being eaten. High pressure will eliminate salmonella in chicken, he explains, and kill parasites in pork, oysters and clams. The technique might also be used to enhance surimi-the fish protein that the Japanese reformulate into fake crab and lobster meat. Farkas says it’s also possible to make a fresh-tasting orange juice with pressure. The Pokka Corp. of Nagoya, Japan, the only other company to sell a pressurized food, combines heat and pressure to make a grapefruit juice it claims is not bitter.
There will surely be more pressurized products on store shelves in the future. The Japanese government and 21 Japanese food and machinery companies have financed a comprehensive study of the processing technique. “The interest level is enormous,” says Philippe Mauguin, director of high-pressure research at the French Ministry of Research in Paris. “European food companies are at least four years behind the Japanese, but we are hoping to catch up.” American food companies have shied away from the technology because of their doubts about the market and the cost of building special pressurizers. Today’s machines are jerry-built with industrial equipment from other industries. However, once proper equipment is designed-and if the Japanese consumers keep snapping up premium-priced pressurized food-Western firms could jump into the market. Mauguin hopes that day comes soon. Pressurized strawberry jam, he reports, is the best he’s ever eaten. And he’s French.
