Food Processing Technology Evolves

“Foods processed with nonthermal techniques are very safe and of excellent nutritional and sensory characteristics,” he says. “The benefits include reasonable cost and the potential for significantly extended shelf life compared to counterparts processed by conventional technologies.”

Nonthermal technologies include high-pressure, pulse electric fields, ultrasound, ultraviolet, dense-phase carbon dioxide, and the use of ozone. Foods that are good candidates for nonthermal processing include fruit juices, egg products, dairy products, oysters, salsas, dips, Spanish tapas, and sliced ham.

“Industrial adoption of these technologies has been slow but steady,” Dr. Barbosa-Cánovas says. “The amount of high-pressure equipment available in the food industry is growing exponentially, with the end result that consumers might pay premium prices for some food products aiming for superior overall quality.”

Novel thermal technologies, including ohmic heating, microwave, and radiofrequency sterilization, are also becoming available at the industrial level. “Nonthermal technologies are mostly utilized for pasteurization processes because of their own limitations,” Dr. Barbosa-Cánovas says. “Without question, there are a significant number of untapped niches for food processors, despite the fact that most nonthermal processes are not currently capable of sterilizing foods.”

One approach getting more attention is what Dr. Barbosa-Cánovas considers “a very neat exception” called pressure-assisted thermal processing, which uses an intelligent combination of time, temperature, and pressure to sterilize foods. “Through a U.S. Department of Defense-sponsored endeavor known as the High Pressure DUST [dual-use science and technology] Program, industry, academia, and the government have been working in partnership for a number of years to explore and develop this concept because the overall quality of the product is very appealing,” he says. The DUST partners are expected to file for approval of the process with the Food and Drug Administration by the end of 2008.

Ultraviolet Technology

John Pierson, leader of FPTD’s Environmental, Energy, and Food Safety Group, is maximizing ultraviolet technology to disinfect liquids like fruit juices, marinades, and brines. “Commercial viability may be here even though ultraviolet light does not penetrate very deep, so only a small amount of liquid can be disinfected at a time,” Pierson says. “U.V. disinfection can offer benefits because heat is not used, so proteins are not denatured.” A recently patented advanced mixing system makes it possible to present liquid uniformly to the light for the same amount of time.

“We have been focused on five-log disinfection of liquids that are relatively opaque to germicidal ultraviolet light,” Pierson says. “Many of these liquids will only transmit the required disinfection intensity less than one millimeter, so systems must have long exposure times or extremely large surface- to-volume ratios.”

The Georgia Tech patented advanced disinfection system addresses both of these issues by controlling the hydrodynamics. Much of the fundamental development has been conducted using computational fluid dynamics (CFD). Five-log disinfection of brines and raw juices has been successfully demonstrated under laminar flow conditions; Pierson and colleagues are now conducting the testing needed for FDA technology verification. The technology is available for licensing, he adds.

Pierson is also addressing water conservation, reuse, and recycling protocols relative to food safety and sanitation. “The goal is to improve food processing water conservation and reuse while ensuring that pathogen reduction strategies are not negatively impacted,” he says. “One application is in poultry processing. The results of pathogen testing are known well after processing. Establishing a methodology for assessing cost-effective solutions will better enable processors to refine their HACCP [hazard analysis and critical control point] plans as they look for improved water conservation and reuse technologies.”

Water usage has become an area that needs advanced sensor concepts and data acquisition and control for process feedback related to pathogen reduction strategies, Pierson says. Unfortunately, reliable sensors for real-time pathogen counts or matrix independent disinfection capacity do not exist. Water usage data is usually collected and logged manually by reading water meters at some frequency. With these limitations in mind, Pierson’s group is working on developing cost-effective technology that can achieve and maintain pathogen reduction.

Mechatronics

Gary McMurray, leader of FPTD’s Automation Group, focuses on mechatronics, a discipline that integrates mechanical design, electrical systems, and software. “Image processing and automation are having a huge impact on the food industry,” he says. “Sensory technology provides vision for a robot to guide its actions.”