Story by Ellen Walker Ternes
Photo illustration by Joshua Harless

University researchers take on food safety

It’s dinner time. Do you know where your food has been? If you’re eating shrimp tonight, there’s a 90 percent chance it was pulled from another country’s waters and processed in a place where food safety might not have the priority it does in the United States.

Prepping a salad? Then it’s pretty certain some of it came from a field that birds fly over, maybe manure fertilizes, and, oh, there could be livestock living in the neighborhood. That means all kinds of bacteria were thriving in the vicinity too, some possibly making it through cleaning and all the way to your table.

Chopped spinach, straight from the freezer? Oops, many bacteria just hibernate in the cold, so if any of the nasty kind of E. coli contaminated machinery that processed your spinach, it could be just waiting to spring back life when it thaws on your counter.

Even in the United States, which has one of the world’s safest food supplies, says Jianghong Meng, professor in the Department of Nutrition and Food Science and acting director of the Joint Institute for Food Safety and Nutrition (jifsan), the Centers for Disease Control estimates that there are 76 million cases of food-borne illness annually. Five thousand cases result in death.

CHANGES IN HOW AMERICANS GET THEIR FOOD, the threat of terrorism and the emergence of drug-resistant bacteria have experts concerned that identifying contaminated food before it does harm is becoming more difficult.

“We have to find ways to detect micro-organisms, toxic chemicals or radiological contamination quickly and in real time.” —mickey parish

The University of Maryland partners with the U.S. Food and Drug Administration in the Joint Institute for Food Safety and Nutrition (jifsan). jifsan is based in Symons Hall and headed by acting director Professor Jianghong Meng (pictured above). In addition to supporting food safety research collaborations, jifsan is helping the United States reduce risk of contamination of imported foods. In its gaps programs—Good Agricultural (and Aquaculture) Practices—jifsan sends experts, including a number of University of Maryland faculty like Martin Lo and Christopher Walsh, to other countries to train government officials and food producers in food safety. jifsan has provided training in 14 countries, many in Central and South America, and, most recently, in China and Korea. “The strategy is to have producers in foreign countries follow U.S. food safety standards for products exported to the United States,” says Meng.—et

Where Americans once raised most of the food they ate, the volume of food imports is exploding. The United States imports 80 percent of its seafood and 40 percent of its produce, yet government officials inspect only a little more than one percent of food that enters the country from abroad. Food law enforcement is divided among many federal agencies, none with enough money or clout to beef up food safety oversight to meet today’s needs.

The possibility of terrorists intentionally contaminating food is a 21st century reality, not just for illness it could cause, says Meng, but for the interruption to the food supply and panic that could result.

Then there are the super bacteria that have evolved from overuse of antibiotics over the last 50 years. Because many food-borne organisms have become resistant to antibiotics, the drugs might not be able to help you if you get sick from bacteria-contaminated food.

THESE FACTORS MAKE THE RESEARCH AND EXPERTISE of University of Maryland food safety researchers crucial. In the lab and in the field, our scientists are learning more about how food becomes contaminated, looking for new ways to prevent food-borne pathogens from making us sick, and teaching safe practices to people in other countries that produce food for the United States.

Mickey Parish, professor and chair of the Department of Nutrition and Food Science in the College of Agriculture and Natural Resources, says, “We need to find the contamination before it causes illness, not work backward after the fact, which is what we often do now. We have to find ways to detect microorganisms, toxic chemicals or radiological contamination quickly and in real time.

“Right now testing a food product may take 24–48 hours or more. The gold standard that everyone is shooting for,” says Parish, “is to be able to find the organism in a one-cup sample, get a result almost immediately and do it inexpensively.”

FINDING THE BAD ACTORS IN FOOD, however, is not a simple process. Foods are extremely complex structures of nutrients, water and organisms. The key, says Parish, is to apply new technology and advances in bioscience to the age-old quest to eat safely.

Meng’s research group is developing a number of methods to detect food-borne viruses and bacteria. One technique uses genetically engineered immune cells that glow fluorescent green when they recognize specific targets, such as E. coli o157:h7, the bacteria responsible for killing people in the 2006 spinach contamination and recent ground beef outbreaks. It is a technique, Meng says, that also could detect a terrorist contamination.

The research team of food science professor Martin Lo is studying how bacteria communicate with each other to accumulate and form a community that produces shields against washing and cleaning. “If we understand more about how they work,” Lo says, “we can come closer to interfering with their operation.”

Another detection method that holds promise is nanotechnology. Researchers in the Department of Nutrition and Food Science will work with the university’s NanoCenter to explore how, for example, nanoscale bacteria detectors could be put inside food containers to send alerts when they sense contaminated food.

ANTIBIOTICS WERE THE MIRACLE DRUGS OF THE 20TH CENTURY. They cured people of life-threatening bacterial diseases and lethal infections. Meat producers gave them to livestock to keep disease away and promote growth efficiency. But overuse of the magic bullet has become a classic case of too much of a good thing.

Amy Chapin Sapkota finds that resistant bacteria from farms, including large livestock operations (below), could contaminate the environment and spread to humans in many different ways.

Amy Chapin Sapkota ’97, assistant professor in the School of Public Health says, “the Union of Concerned Scientists estimates 24.6 million pounds of antibiotics are given to healthy livestock annually in the United States. That compares to approximately three million pounds prescribed to treat humans.”

So, while the antibiotics were successfully doing their jobs, bacteria were busy surviving by genetically altering to resist the drugs. To complicate matters, says Meng, one of the world’s leading researchers on antibiotic resistance in food, “We have found that if bacteria are exposed to one antibiotic or chemical, it may develop resistance to others at the same time. We have a situation that is creating multi-drug resistant bacteria.”

In one of his studies, Meng tested bacteria on meat from grocery stores. “We found that many of the bacteria on the meat—Salmonella, E. coli, and Campylobacter—had developed resistance to antibiotics used to treat infections in people.” Meng’s work contributed to a Food and Drug Administration decision to ban use of a sister drug of the antibiotic Cipro in poultry.

Sapkota also studies antibiotic resistant bacteria, but she goes directly to the source of antibiotic resistance in the food chain—the farm itself. She studies how humans are exposed to pathogens that get into the water, air and soil around large livestock operations. One of her studies was the first to find that antibiotic-resistant bacteria from large-scale swine facilities travel through the air. “Environmental pathways of human exposure may be as important as food-borne pathways,” Sapkota says. “Resistant bacteria from farms could contaminate the environment and spread to humans in many different ways.”

THE IMPACT OF MARYLAND'S food safety research and expertise will grow as research continues and new efforts are launched. For example, the Center for Food Systems Security and Safety, endowed by a $1.2 million gift from Robert Facchina ’77, president and ceo of Johanna Foods, has recently begun its work to find ways to secure food production supply systems to insure public safety from intentional and unintentional food contamination.

Faculty research on quick detection of food-borne pathogens may pay off sooner rather than later, says Meng. “Several advanced technologies are able to identify and detect food-borne pathogens in real time, within minutes. Although it may take some years for such technologies to be applied directly to food, it’s a reachable goal.”

In the meantime, each one of these highly educated experts, who work with contaminating organisms all the time, says the most important thing they do to avoid illness from food contamination is what our parents and home economics teachers have told us for generations: Wash your hands, often and well. TERP

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