WASHINGTON -- A Baltimore company received yesterday the first permission that federal food regulators have ever granted for killing a common but sometimes deadly bacteria with a mixture of viruses added to foods.
The mixture of six viruses, developed by Intralytix Inc., aims to sharply reduce the 500 deaths and 2,500 illnesses caused in Americans each year by exposure to the bacteria often present in some uncooked meats and poultry. After four years of review, the Food and Drug Administration said the antimicrobial combination was safe and works in deli meats and other ready-to-eat foods.
John Vazzana, chief executive officer of Intralytix, described the approval of the mixture as a "huge milestone" in the fight against bacteria and antibiotic-resistant bacteria that cause food-borne illnesses. The viruses, he said, "are very specific, and they won't kill or destroy any other organism that is there. The only thing they will do is kill their target bacteria."
The combination of viruses that Intralytix developed kills various strains of the Listeria monocytogenes bacteria, a widely occurring microbe that especially sickens pregnant women, their fetuses and adults with weakened immune systems.
Before final processing, food manufacturers would spray the mixture on sliced ham, turkey and other foods that usually aren't cooked or reheated before eaten. Cooking and reheating, as well as processing, kills the Listeria bacteria, but foods can become contaminated after processing or even while sitting in a refrigerator.
Judged safe, effective
Consumers shouldn't notice any difference in the taste or color of foods sprayed with the mixture of bacteriophages, as the bacteria-killing viruses are called, the FDA said. Also, the agency found Intralytix's recipe safe and effective even among men in their 20s, who eat the largest quantities of ready-to-eat foods and consequently would ingest the largest amounts of the viruses.
Doug Gurian-Sherman, a senior scientist at the Center for Food Safety, a nonprofit public advocacy group based in Washington, said bacteriophages were safely used in the Soviet Union to kill bacteria during surgeries and other medical treatments. He said the only possible harm he could envision from the viruses' use as a food additive was allergic reactions in some people.
"But that's always an issue, and we are exposed to these things all of the time," he said. "I generally wouldn't be concerned about it."
In its application for FDA approval, Intralytix said it would purify the viruses during manufacture to reduce any potential for allergic reactions. An FDA review of studies on the company's combination of viruses, completed earlier this year, found that they were safe and effective, including for children. The U.S. Department of Agriculture will provide additional regulation, monitoring its actual use in foods.
"As long as it is used in accordance with the regulations, we have concluded it's safe," said Andrew J. Zajac, of the FDA's office of food additive safety.
The illness caused by the Listeria bacteria carries flu-like symptoms, such as fever, muscle aches and sometimes, stomach pains. It can lead to severe headaches, a stiff neck, loss of balance and convulsions.
Food manufacturers have been searching for additives that would target Listeria, Salmonella and other bacteria that sicken consumers. They have relied on antibiotics to kill bacteria, but the microbes have developed resistance to some of those drugs.
Although the incidence of listeriosis is rare among the 76 million food-borne illnesses contracted each year, it's responsible for a disproportionately large percentage of hospitalizations and for many deaths.
Since 1987, regulators have been sampling ready-to-eat foods for the bacteria, but the sampling process destroys the product and thus can't be widely applied, according to the American Meat Institute, an industry association.
Julie DeYoung, a spokeswoman for Perdue Farms in Salisbury, said the chicken processor would consider using Intralytix's mixture. "The industry is always looking for more effective ways to control pathogens in the processing environment," she said.
Perdue awarded $1 million to Intralytix to spur the development of viruses that would fight Listeria and Salmonella, Vazzana said.
Based in Camden Yards, Intralytix was founded in 1998 to develop viruses that would attack antibiotic-resistant bacteria in humans, Vazzana said. The company, which has 12 employees, finished developing the anti-Listeria mixture in 2001 and asked the FDA to approve it in 2002. It has licensed the product for marketing and sale to another company, which Vazzana declined to disclose.
In the next year or so, Vazzana said, Intralytix plans to seek FDA approval for bacteriophage products against E. coli and Salmonella.
The Associated Press contributed to this article.