Colorado State University Extension
SafeFood Rapid Response Network
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IN THE NEWS
Edited by: Stephanie Wallner, M.S., Mary Schroeder, M.S., R.D, Pat Kendall, Ph.D., R.D., Colorado State - Fall 2006
CSU-OSU RESEARCHERS TO STUDY LISTERIA IN THE FARM-HOME ENVIRONMENT
Food microbiologists and consumer behavior researchers at Colorado State University and The Ohio State University are on a mission to better understand how a bacterium like Listeria monocytogenes gets into your kitchen. Listeriosis is a fairly rare foodborne disease, but one with a high risk of fatality; of the 2,500 Americans who get the disease each year, 500 (20%) die. Those at greatest risk are pregnant women and their fetuses, infants, the elderly and persons with challenged immune systems.
Listeriosis made headlines in 1998 when 40 people in 10 states became ill and four died. The outbreak was traced to contaminated hot dogs that were eaten cold or undercooked. Despite similar periodic outbreaks, the vast majority of listeriosis cases occur sporadically.
This fall, Pat Kendall and John Sofos at CSU along with Lydia Medeiros and Jeff LeJeune at OSU received a $600,000 grant to better understand how sporadic cases of listeriosis are spread. The study, entitled "Incidence, Significance, and Control of Listeria monocytogenes in the Home Environment," is funded through the National Integrated Food Safety Initiativeby the Cooperative State Research, Education, and Extension Service.
At each university, researchers are looking for 25 families who live on farms with cows, sheep or other ruminant animals, and 25 other rural families who don't have regular contact with ruminants. Ruminants tend to get Listeria in their digestive tract and shed it in their feces, often without any signs of illness.
As noted by LeJeune at OSU, "We are looking at this as an occupational safety and health issue. Are farm families more exposed to Listeria monocytogenes? Are farmers bringing their work home with them -- literally -- on their clothing? If that is occurring, how can we interrupt the pattern?" The researchers need other families -- those who don't live around ruminant animals -- to act as controls. "It could be that this stuff is everywhere," LeJeune said. "If we find it in farm households, we need a comparison of non-farm households to determine if it's farm-related." The study will shed light on how foodborne illnesses can spread.
Participants are being asked to complete a questionnaire and participate in an interview about their food preparation and other household practices. Then, the researchers go through the house with a family member to collect samples and schedule three more visits on a monthly basis. Any Listeria bacteria found will be DNA-typed to determine if bacteria found in different places came from the same source. The findings will help the researchers guide both consumers and farm families on what they can do to prevent listeriosis in their homes.
To learn more about the study or for additional details about participating, contact Ruth Inglis-Widrick at (970) 491-3747 or inglis@cahs.colostate.edu.
THE FUTURE OF FOOD SAFETY: NANO-PARTICLES
by Diane Braithwaite
CSU FSHN Master's Candidate and Intern
Nanotechnology has had a place in electronics for some time and is now finding a new home in the food industry. These tiny particles are being researched for a variety of applications from sensing biological agents to enhancing flavor.
What is nanotechnology? Nanotechnology refers to technology on a nanometer scale, specifically less than 100 nanometers. The original nano-particles used in this technology are tiny spheres (fullerenes) or tubes (nanotubes) made from carbon atoms. New nano-particles are being made of silicon, ceramic, polymers or even natural ingredients that break down in the body. Some of the characteristics that make these particles useful in the food industry include optical properties, reactivity to temperature, and biodegradability. They can be used as probes or filled with flavorings or nutrients for delivery.
Nano-particles in food safety: One application for nano-particles being researched is detection of bacterial contamination. Qingrong Huang of Rutgers University is working on a portable device using the fluorescent property of nano-particles. Nano-particles made from silicon-containing materials will be used to create a chip for the device. When DNA probes embedded in the nano-particle chip make contact with the DNA of a pathogen, it will cause the material to fluoresce. Huang's focus for this device is to detect E. coli and Listeria.
Incorporating nanotechnology into food packaging is another potential way to monitor for spoilage. Researchers are developing the "electronic tongue," a type of packaging embedded with nano-sensors for detecting pathogens. The packaging is being designed to fluoresce or change color when the nano-sensors detect pathogens or chemicals released as the foods spoil. Another twist on nano-sensors within packaging is the development of "release on command" preservatives, which release as the food begins to spoil.
Controversial use of nano-particles: A more controversial use of nano-particles is as flavor enhancers or nutrient delivery mechanisms. Nano-particles can be designed to encapsulate substances which degrade in acidic conditions or in response to the small intestine, allowing for more effective delivery of nutrients or medicines. This can also prolong the shelf life of products like omega-3 oils. One beverage company is working to encapsulate flavor compounds to extend shelf time. More research is needed to learn what effects nano-particles might have on the body or environment.
Sources:
- Goho, A. Hungry for Nano: The fruits of nanotechnology could transform the food industry. Science News, 2004; 166: 200-201.
- Wolfe, J. Safer and guilt-free nano foods. http://www.forbes.com. Accessed 02/10/2006.
