Food Safety & Nutrition News

"It's our duty to the people of South Carolina, whether we're in research, Extension or regulatory programs," said Susan Barefoot, director of the School of Applied Science and Agribusiness and assistant director of the S.C. Agriculture and Forestry Research System and the Clemson University Cooperative Extension Service.

That's one reason Clemson is hosting a Food Safety Symposium April 15-16, so that anyone interested in the issue can take a look at how America's food supply will be kept safe for consumers in the future. The symposium opens at 12:45 p.m. on April 15 at the Madren Center on the Clemson University campus.

"We already have one of the safest food supplies in the world, but a look at the statistics shows there's still room for improvement," she said.

Barefoot noted that foodborne illness hits between 3.3 and 12.3 million Americans each year, kills around 3,900, and costs an estimated $35 billion in medical expenses and loss of production.

What makes people sick is not what a lot of people worry about -- pesticides and environmental contaminants -- but simple microbes such as E. coli, salmonella, listeria, campylobacter, staphylococcus and less famous cousins such as shigella, several Vibrio species and other bacteria.

Catherine Woteki, under secretary for food safety in the U.S. Department of Agriculture, and other experts will talk about steps being taken to develop more effective control measures for pathogens during the Food Safety Symposium.

Barefoot, a food scientist, said it is not practical to expect all of our foods, whether meats or fruits and vegetables, to be perfectly free of microbes.

"They are everywhere, and that makes it important for us to understand how they get into our foods, how to control their growth and how to limit their access to our foods," she said. To do that, 14 faculty members from five departments in three colleges are involved in food safety research. The expertise ranges from molecular biology, microbiology and biochemistry to muscle food applications and food packaging.

In addition, she pointed out that Clemson Extension experts train food service workers, small food processors and others who handle food products in proper procedures that reduce the risk from foodborne pathogens.

She also noted that Clemson's Livestock-Poultry Health Program helps protect the health of both humans and animals while protecting the state's $1.6 billion livestock, poultry and companion animal industry.

On the research side, Barefoot said several faculty are working with bacteriocins, proteins produced by lactic acid bacteria (LABs).

"You could call them killer proteins," she said. "We use them to kill bad bacteria and prolong shelf life."

LABs and their bacteriocins are essential elements in foods such as yogurt, cheese, sauerkraut, pickles and sourdough bread. The lactic acid produced by the bacteria acts as a preservative, and the bacteriocins prevent competing bacteria from gaining a foothold.

"Bacteriocins are not antibiotics, but they act a lot like them," Barefoot said.

Paul Dawson, associate professor of food science and human nutrition, has combined food-grade antimicrobials -- he calls them biocides -- with heat-set films made from proteins and polyethylene.

The biocides include nisin, a bacteriocin and an approved food additive used in cheese spreads and liquid egg; lysosyme, an enzyme found naturally in egg white; EDTA, another approved food additive; and fatty acids.

"I don't know when these films might be commercially available," Dawson said. When they are, the films will make the food products they protect safer for consumers. The films are being tested on meat products and specific pathogens such as Salmonella enteriditis, Listeria monocytogenes and E. coli.

The federal government has mandated pathogen reduction in processing plants. So James Acton, Stender Professor in food science, is looking at nisin, salts and other compounds as antimicrobial rinses for fresh meats and at bacterial cultures in fermented meats such as sausages to inhibit pathogens. Acton and Dawson work together on the food-grade rinses.

Ashby Bodine, professor of animal and veterinary science, is purifying and analyzing bacteriocin and bacteriocin-like proteins that are active against certain bacteria. He hopes to produce enough active bacteriocin to allow collaborators to determine the gene sequence, which will, in turn, allow researchers to study the way bacteriocins inhibit bacteria.

Annel Greene is working with one bacteriocin that may inhibit spoilage microorganisms in horticultural crops in the field, and another that could be incorporated into food products such as cream-filled doughnuts to protect against staphylococcus.

Food scientists Ronald Galyean and Felix Barron are developing a small pasteurization system that could be a boon to apple cider lovers.

"Apple cider producers in the state don't pasteurize their product to kill any bacteria that might have contaminated it, and if this system proves effective and economical, it could make roadside cider sales a lot safer," Barefoot said.

Mickey Hall, Extension poultry specialist for small flocks, is looking at ways to reduce pathogen levels in ostriches and emus so carcass processing can be simplified. She is also looking at the shelf life of ratite meat under different packaging atmospheres and films.

Research does not always turn out as expected, according to Barefoot. One of the bacteriocins she identified turned out not to have a food application. However, it does kill bacteria that cause acne.

"Our patent has been granted," she said. "Next, we'll have to find a partner to market it."

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DATE: 7-5-96

CONTACT: Susan Barefoot, (864) 656-5682 sbrft@clemson.edu

WRITER: Mike McCombs, (864) 656-1222

CLEMSON MICROBIOLOGISTS STUDY NATURAL FOOD PRESERVATIVES

CLEMSON - An international project led by two Clemson University scientists could help identify a gene to make foods safer and longer lasting.

The Clemson researchers recently received a USDA Binational Agricultural Research and Development Grant of $96,588 for a research project investigating the proteins produced by bacteria that are used to make foods such as Swiss cheese.

Clemson microbiologists Susan Barefoot and Thomas Hughes will work with researchers from Iowa State University and Israel's Volcani Institute on the project.

The researchers are looking for the gene that generates the bacteriocin that prevents foods from spoiling quickly. Bacteriocins are proteins that act as natural preservatives.

Since not much is actually known about these genes, the researchers are interested in marking them for further study. Then the gene might be transferred into other types of bacteria and used to preserve other food products.

"There are three major benefits of this research," said Barefoot, a member of the Agriculture and Forestry Research System at Clemson. "First we'll understand how to produce these bacteriocins better and in larger quantities for use as food preservatives. Secondly, someone else could take what we learn and use it for other applications. Finally, the genes could be transferred into other bacteria that make food products to help them produce more than one bacteriocin to guard against food-borne illness."

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DATE: 12-13-96

CONTACT: Susan Barefoot, (864) 656-5682 sbrft@clemson.edu

WRITER: Debbie Dalhouse, (864) 656-0937 ddalhou@clemson.edu

NEW ACNE TREATMENT DISCOVERED BY CLEMSON UNIVERSITY RESEARCHERS

CLEMSON -- A possible new acne treatment has been identified by Clemson University food microbiologist Susan Barefoot and Ph.D. student Priya Ratnam. Barefoot is a researcher with the South Carolina Agriculture and Forestry Research System based at Clemson, with a joint appointment in food science and microbiology. Barefoot's research is also part of the Greenville Hospital System - Clemson University Biomedical Cooperative which supports biomedical research between the two institutions.

The discovery came about as a result of investigations into proteins that act as natural food preservatives. One of these proteins can be used to extend the shelf life of yogurt. Called a bacteriocin, the protein is a tiny bit of matter produced by bacteria.

"It was really serendipity," Barefoot said. "The bacteriocin that inhibits the yogurt bacteria is produced by a close relative of the organism that inhibits the acne bacteria. I discussed the concept with my colleagues and we wondered if a similar approach would be effective against the acne bacteria."

Through the Greenville Hospital System Biomedical Cooperative, Barefoot secured blackheads from doctors Eric Baker and Patricia Westmoreland, dermatologists with the Greenville Hospital System. The Clemson researchers then isolated 150 acne bacteria from the blackheads. The bacteriocin was tested against the 150 cultures, using two different methods.

"The acne bacteria was controlled in every single test," Barefoot said. "Every strain, every culture, both testing methods - all had the same results."

Scientific investigators do not expect 100-percent success rates, so Barefoot and her colleagues are somewhat incredulous and cautious about their findings.

However, the initial findings were presented at the Interscience Conference on Antimicrobial Agents and Chemotherapy in New Orleans in September and have generated a great deal of interest among microbiologists. The concept is now protected with a provisional patent to allow further testing.

"First we must understand how it works and develop a method to produce enough bacteriocin for further testing," Barefoot said.

Producing the promising bacteriocin is comparable to generating 55 gallons of material to collect a tiny straight pin of usable product, said Barefoot. Because of the technical challenges, it will probably be several years before the product can begin clinical trials.

If it stands up to the additional testing, the Clemson discovery could hold tremendous promise as a topical treatment for millions of acne sufferers around the world.

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DATE: 12-18-95

CONTACT: Budd Bodine, (864) 656-3120 abodine@clemson.edu

WRITER: Debbie Dalhouse, 864/656-0937

CLEMSON SCIENTIST STUDIES SHARK IMMUNE SYSTEM

CLEMSON -- A biochemist in Clemson University's Animal, Dairy and Veterinary Sciences department has spent more than a decade studying sharks from Florida in an effort to unlock the secrets of the shark's immune system, and apparent resistance to cancer.

Since 1982, Budd Bodine from Clemson has worked with Carl Luer, a biochemist at the Mote Marine Laboratory in Sarasota, Florida, to gain a better understanding of the mechanisms involved in the shark's natural resistance to cancer. The two scientists hope their findings may someday be applied to cancer treatments in humans.

Before adding sharks to his research repertoire, Bodine had studied the effects of aflatoxin on the reproductive and immune systems of dairy cows and other livestock as part of his role as a professor at Clemson University. Aflatoxin is a toxin and carcinogen that is produced by a fungus on agricultural commodities such as corn and peanuts in the Southeast.

While Bodine was studying the effects of aflatoxin on farm animals; Luer was also studying the carcinogen, but was using sharks as his research subjects. In fact, Luer was attempting to cause cancer in the sharks by dosing them with aflatoxin. Bodine realized that to advance his own research, he needed to understand the immune system of the shark. In turn, he had the technology for tissue and toxin analyses that Luer needed for his work.

Thus began a collaboration that has lasted over the years, and produced some promising findings.

After a decade of research, Bodine and Luer discovered that none of the sharks developed cancer even when they were given doses of aflatoxin in a variety of concentrations. They also found that the shark's apparent resistance to certain cancers seems to lie in its ability to inhibit the growth and spread of blood vessels associated with a tumor.

The two scientists now have extended their comparative research studies with sharks and skates, and are currently investigating the role that the thymus gland plays in these fishes' immune systems.

In addition, Bodine and Luer have discovered a protein which can speed up growth of certain cell types in mammals and birds, and are presently searching for factors which can slow down the cells' growth.

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