Putting the Squeeze on Germs

Instinct has always told us to squash bugs before they get us. Now, dangerous germs such as E. coli and salmonella get the same treatment from a machine that uses the simplest of substances--water--to crush these food-poisoning threats without mangling the food itself.

The high-pressure pasteurizing machine, dubbed “Fresher Under Pressure” by its maker, FlowInternational, uses as much as 100,000 pounds per square inch of water pressure to choke harmful microorganisms without changing the food’s look, taste, nutrition or texture.

Chicken-on-the-bone pops back up intact; fruit emerges unscathed. Even oysters in the shell emerge looking exactly the same--although the pressure causes them to shuck themselves, a side effect oystermen are understandably happy about. The key is perfectly even distribution of pressure. Although the volume of most food placed in the Flow machine’s pressure chamber is compressed by 15%, water molecules in most moist food provide the structure necessary for it to spring back.

“If you were to take a plastic bottle of water and drop a grape in that bottle, and squeeze that bottle, you couldn’t crush that grape” because the pressure is so even, Flow Chief Executive Ron Tarrant said.

In contrast with other areas of consumers’ lives in which new technological innovations are being introduced almost every month, food safety has seen relatively few advances in the last century.

Although some large meat companies are beginning to use electronic irradiation to blast germs, most firms still use the same age-old techniques to kill germs such as high-temperature cooking, freezing and pickling. And with consumers demanding more fresh or at the very least, fresher tasting foods, these techniques aren’t exactly practical.

So food companies have begun scouting for new germ-killing methods, or more powerful versions of ancient practices.

“I think there could be some significant increase in safety using some techniques that your grandmother might have known about but that haven’t been used widely in the food industry,” said Caroline Smith DeWaal of the Center for Science in the Public Interest. If Flow has its way, its high-pressure treatment could change what consumers eat in the years ahead. Canned goods could begin to be supplanted in supermarkets with fresher-tasting food in vacuum-packed bags.

Flow is working with big food companies such as Kraft Foods and ConAgra to develop unrefrigerated products such as macaroni and cheese and soup that don’t have to be subjected to extreme heat for long periods.

Guacamole makers and juice makers such as Odwalla were among the first to adopt the “fresher under pressure” system because they didn’t want to heat treat their products and lose the fresh taste and vitamins. Now, other food companies are slowly following.

Hormel Foods has begun using the process on prosciutto and plans to use it on other deli meats. Shellfish distributors on the Gulf Coast and in Washington state are using it to market a line of safer oysters. And chicken giant Perdue Farms will begin using it on roasted whole chickens, squashing them in shrink-wrapped bags to keep them safe and on the shelf longer.

At a recent processed-food convention in New Orleans, some food scientists were calling it one of the most intriguing new technologies in food safety the industry has seen in a long time. That is, if its maker can find a way to make it more economical. Machines start at $800,000 and run to $2 million.

“It looks promising,” said Christine Bruhn, a food scientist at UC Davis.

That’s if Flow can prove to the Food and Drug Administration that the process produces safe food and won’t contain dangerous botulism spores that thrive in these types of sealed environments.

Flow didn’t have to seek anyone’s permission to begin selling its germ crusher for use on fresh refrigerated food. Because the machine does not add anything to the food and its products are kept cool, the FDA doesn’t view it as a risk. Although, the agency said it is independently reviewing its effectiveness on oysters.

Flow developed and patented the prototype for the germ crusher in the early 1990s in conjunction with food science researchers from Oregon State University, who were trying to develop longer-lasting and better-tasting rations for the U.S. Army.

The process wasn’t entirely new. Some juice and jam makers in Japan and France had begun using a similar machine on a small scale. And the concept behind it was more than a century old, said Edmund Ting, Flow’s vice president of research and development.

“There was a lot of preexisting science on this going back to the 1890s, where people made the observations that when fruit and meat were subjected to high pressure they lasted longer,” Ting said.

Each type of bacteria takes a different amount of pressure to kill. Vibrio vulnificus, the deadly bacteria in oysters, is easiest. Listeria monocytogenes, the hardy bacteria found in deli products such as hot dogs and luncheon meat, is the toughest--requiring about 87,000 pounds per square inch of pressure.

The demand for new technologies such as these began in earnest in the mid-1990s, after a number of high-profile food scares such as Jack in the Box’s massive E. coli outbreak in 1993, and big food recalls began stealing headlines. All of a sudden consumers began paying more attention to whether food was handled properly. And a number of large recalls has kept the issue at the top of food shoppers’ minds, said Jeffrey Barach, vice president of the National Food Processors Assn.

“E. coli, salmonella and listeria--those microorganism names have become more and more common in discussion,” Barach said. That, in turn, put pressure on food companies to sanitize their food, but most were concerned the usual processes such as high temperature cooking, freezing and acidic treatments would dull the fresh taste and dampen demand for their products.

So some meat and produce companies have begun turning to new technologies such as electronic irradiation and radiation from ultraviolet light to kill germs without altering the flavor or texture of foods.

“You wouldn’t want to cook a product like [prosciutto],” said Joe Swedberg, a vice president of marketing for Hormel.

Still, these new high-tech treatments are no guarantee of safety, scientists say, especially if goods are packaged incorrectly. And Flow’s machine doesn’t work on every kind of food. Although it can pasteurize cooked chicken without a noticeable difference in appearance or taste, it can’t do the same for raw poultry, Ting said. The color and flavor are affected.

It can’t be used on dry foods such as bread or on foods with air puffed in such as marshmallows. These come out of the machine looking like marbles, Tarrant said. Moreover, it hasn’t been proved to kill other food threats such as botulism spores, viruses or prions believed to cause “mad cow” disease or bovine spongiform encephalopathy. That research is still being conducted.

Perhaps the biggest deterrent is the price. At as much as $2 million, the machines are a major investment for any food company, let alone a small family-owned firm looking to protect itself.

Because food makers have to crush food in small batches, it slows down production. But for large companies that can afford it, such as Hormel, its increased cost raises the price per pound only a few cents--a small price to pay for a great measure of safety, Tarrant said.

Some companies such as Nisbet Oyster Co. in Bay Center, Wash., will save money using the equipment because they don’t have to hire people to shuck their oysters.

Some might even use it for that benefit alone.

“Vibrio [vulnificus] is not a problem for us,” said Dave Nisbet, who processes about 70,000 pounds of oysters a day. “I was just amazed that high pressure could perfectly shuck an oyster with no cuts and wouldn’t affect the texture or taste of the oyster.”

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Times staff writer Melinda Fulmer covers agriculture and the food industry.

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How It Works

* A graphical look at the germ-crushing machine. T6