From: Food Quality & Safety magazine, April/May 2011

Novel Approaches to Pathogen Control

Lactates, diacetates, irradiation, and high pressure are drawing increased interest in the pre- and post-packaging stages

by Peter Gwynne

Novel Approaches to Pathogen Control

A series of recent incidents involving pathogens in peanut butter, ground beef, and chicken products has forced the food industry to recognize the continuing need for technological means of ensuring the biological integrity of food supplies.

That need is fueling the efforts of industry experts to embrace and advocate novel approaches to pathogen control.

“Our objective is to find the practical implementations that can be used immediately,” says Kenny Lum, president of the Seafood Products Association (SPA), which organized the Food Pathogen Intervention Symposium on April 27 in Seattle.

Technical Tools

The need for technical tools to combat pathogens has been bolstered in recent years by consumers’ growing demand for foods that receive minimal processing. The popularity of farmers’ markets and food cooperatives as sources of locally produced foods, as well as the burgeoning demand for organic foods, puts extra pressure on safety measures.

“There’s a recognition that for some food products out there we maybe don’t have the right interventions in place, or we didn’t recognize that we needed interventions,” Lum explained. “Non- or minimally processed foods are really our focus. We know there’s risk there that we can mitigate with intervention.”

That mitigation will focus mainly on the use of featured technologies to combat the common pathogens E. coli, Listeria, and Salmonella. “These are generally the most resistant,” said Subba Rae Gurram, SPA’s director of process technology. “We’re trying to aim at pathogens that would be logically targeted. In the process of controlling those, we’ll probably be controlling others.”

Pathogen experts are touting a smorgasbord of technical fixes.

“We’ve tried to identify things we can do to food before it’s packaged, and then things that are active in the packaging, such as lactates and diacetates, and products like irradiation and high pressure that can be used post-packaging,” Lum said. “We’ll also have a lot of discussions about hurdles technology—the idea of multiple barriers to specific food pathogens. Some of the technologies have been around for a time while others are relatively new. It’s a matter of trying to identify the applications and where they can work.”

High-pressure processing features water under very high hydrostatic pressure to produce packaged foods that some advocates say are safer, last longer, and are more natural and better-tasting.

Advances in Post-Packaging

Non-thermal post-packaging methods represent the most recent developments and improvements in intervention technologies.

Jacek Jaczynski, associate professor of food safety at West Virginia University, advocates the advantages of electron beam processing. This emerging technology has found some use in treating fruits and vegetables. It offers particular application benefit because the electrons penetrate no more than a few microns.

Research teams have recently started to apply the technology to new foods. Jaczynski has participated in studies of e-beam’s value in reducing the presence of Salmonella strains in peanut butter. They have shown, in particular, that e-beam irradiation is an effective means of killing bacteria without the application of heat. Boosting the research studies is evidence that consumers’ suspicion of any food irradiation technology is decreasing.

Errol Raghubeer, vice president of food microbiology and food technology at Avure Technology Inc. in Kent, Wash., emphasizes the growth of high-pressure processing. This technique features water under very high hydrostatic pressure to produce packaged foods that, according to Avure, “are safer, longer lasting, more natural, and better tasting.” Pasteurization systems that use pressures up to 100,000 pounds per square inch can destroy several pathogens, notably E. coli, Listeria, and Salmonella, while causing little change to the organoleptic properties and nutritional value of foods. Application areas include sliced meats, processed fruits and vegetables, fresh juices and smoothies, and delicatessen salads and dips.

Another technology is relatively well established in theory but less in practice. “Some of the bacteriophages are underutilized,” Lum said. Alexander Sulakvelidze, chief scientist of biotechnology firm Intralytix in Baltimore, Md., calls the use of these ubiquitous bacteria-infecting viruses “natural, non-toxic, safe, and effective means for significantly reducing or eliminating disease-causing bacteria that are sometimes present on foods.” The company has developed bacteriophage-based products that target such pathogens as Listeria monocytogenes and E. coli O157:H7. It has under development phage-based products against other pathogens responsible for threatening food safety.

“Some of the bacteriophages are underutilized. (They are) natural, non-toxic, safe, and effective means for significantly reducing or eliminating disease-causing bacteria.”

—Alexander Sulakvelidze, chief scientist at Intralytix, Baltimore, Md.

Older Methods, Other Issues

Ozone received approval from the U.S. Food and Drug Administration as an antimicrobial agent for food in 2001. Initially, it was used only as a sanitizing agent. John Brandt, president and cofounder of Ozone International in Bainbridge Island, Wash., advocates ozone’s value for cleaning in addition to sanitizing. The triple-atom form of oxygen decomposes fat and grease far more rapidly than chlorine.

Other established techniques include ultraviolet light, acidified sodium chloride, lactates, and di-actetates that are active in food packaging, and antimicrobial packaging and edible coatings. But beyond hard science and technology, matters of policy and sociology also will play key roles in the pathogen-control debate.

Advocates, Lum says, will focus on the need to address consumers’ concerns about the use of intervention technologies that, because of unfortunate associations, can give the appearance of more threat than promise. For many consumers, irradiation—whether with electron beams or other entities—conjures visions of malfunctioning nuclear reactors. And ozone is an atmospheric pollutant rather than a cleanser. Overcoming those concerns with solid data will ease the way for the adoption of new pathogen-fighting techniques.

Peter Gwynne is a freelance science writer and editor based on Cape Cod, Mass.. In addition to food science, he covers physics, biotechnology, and policy issues for a variety of publications.



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