Bacteria-Eating Virus Approved as Food Additive

FDA Consumer magazine (Jan-Feb 2007)

 

Not all viruses harm people. The Food and Drug Administration has approved a mixture of viruses as a food additive to protect people. The additive can be used in processing plants for spraying onto ready-to-eat meat and poultry products to protect consumers from the potentially life-threatening bacterium Listeria monocytogenes (L. monocytogenes).

The viruses used in the additive are known as bacteriophages. Bacteriophage means "bacteria eater." A bacteriophage, also called a phage (pronounced fayj), is any virus that infects bacteria.

Consuming food contaminated with the bacterium L. monocytogenes can cause an infectious disease, listeriosis, which is rarely serious in healthy adults and children, but can be severe and even deadly in pregnant women, newborns, older people, and people with weakened immune systems. Pregnant women are about 20 times more likely than other healthy adults to get listeriosis, according to the Centers for Disease Control and Prevention (CDC). Listeriosis can cause miscarriage, stillbirth, premature delivery, or death of a newborn baby.

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The type of phage that was approved is lytic, which means that the phage destroys its host during its life cycle without integrating into the host genome. This type of phage works by attaching itself to a bacterium and injecting its genetic material into the cell. The phage takes over the metabolic machinery of the bacterium, forcing it to produce hundreds of new phages and causing the bacterial cell walls to break open. This process kills the bacterium and releases many new phages, which seek out other bacteria to invade and repeat the cycle.

"The process continues until all host bacteria have been destroyed," says Zajac. "Then the bacteriophages cease replicating. They need a host to multiply and will gradually become inactive when they lose the host."

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Labeling

Under the Federal Meat Inspection Act and the Poultry Products Inspection Act, both administered by the USDA, the use of the phage preparation must be declared on labeling as an ingredient. Consumers will see "bacteriophage preparation" on the label of meat or poultry products that have been treated with the food additive.

If consumers have any concerns about what they're getting at the deli counter, says Post, "they always have the ability to ask for the label of the product being prepared or sliced to see what it contains."

A Phage First

This approval marks the first time that the FDA has regulated the use of a phage preparation as a food additive. Phages are currently approved in the United States for pesticide applications, such as spraying on crops.

Scientists continue to be interested in other uses for phages, such as to prevent food products from contamination with other types of harmful bacteria and to act as possible treatments for bacterial infections in people.