Graduate student Melinda Hayman prepares a batch for high-pressure processing. A growing public demand for milk-based products that avoid the “cooked” fl avor that accompanies pasteurization has increased interest in the process.

Food science and other disciplines are responding to these changes with a tidal wave of innovation. An important part of this renaissance is the emergence of functional foods—something Floros says has been a long time coming. “Connecting food to health and wellness is something we’ve always done as food scientists but never really advertised very well,” he says. “The nutritionists always talk about how nutrients affect the body, while food scientists have always looked at the whole food. What one nutrient does may or may not be the same as when that nutrient is part of the whole food. So we study how complex combinations of nutrients and whole food affect health and wellness. Also, much of the connection between food and health has to do with safety—microbial and chemical safety.”

Cooking with heat, Floros explains, remains the single most effective way to kill microbes. However, a food or ingredient that is pasteurized or otherwise exposed to heat may also change or degrade. Irradiation, which does not rely on heat, sterilizes food effectively but is unpopular because most people are leery of the finished product. Researchers are developing several promising nonthermal technologies—such as very high pressure, exposure to ozone and chlorine dioxide, and antimicrobial packaging— that can make food safer without affecting its quality.

Which takes us back to Anantheswaran’s and Knabel’s work in highpressure processing. Subjecting foods to hydrostatic pressures of 50,000 to 100,000 pounds per square inch is like balancing three elephants on top of a dime, Knabel explains. Th ose pressures achieve a “cold pasteurization,” killing Salmonella, Listeria monocytogenes, and other microbes. And the food does not get as flat as you might expect.

“Unlike heat, the pressure is transmitted instantaneously and uniformly throughout water-based food products, keeping the food from being crushed,” he says. “It’s compressed a little but returns to its original shape when the pressure is released. And, while cooking makes the outside hotter than the inside, there’s no gradient of effectiveness from outside to inside with hydrostatic pressure. The hydrostatic pressure process can be done as a batch system: Food is packaged in a flexible, plastic container and then placed into a water-filled chamber. The chamber is closed and the pressure applied. After high-pressure processing, most products remain virtually unchanged, and such high-acid foods as juices, jellies, fruits, yogurts, and tomato products reap a surprising flavor benefit compared to heat processing. Food tastes fresh rather than cooked and retains many of the nutritional advantages of raw foods.”