Could Irradiation Kill Anthrax?

B O S T O N, Oct. 18, 2001 -- As fears build over the spread of anthrax through the postal system, debate is emerging over whether the bacteria can be killed before it causes any harm.

Suggestions on how to decontaminate mail range from microwaving to household irons. In a laboratory setting, bacteria and bacterial spores are routinely killed with bleach, or by exposure to extremely high heat in what is called an autoclave.

But many experts agree that there is very little, if anything, you can do to kill bacteria short of destroying your mail.

"Steam irons are not going to get you where you need to be," said Dr. John Clements of Tulane University in New Orleans.

Can Irradiation Kill Anthrax?

There is a technology that certain companies believe will kill anthrax — irradiation.

Titan Corp. suggests its irradiation technology, currently used to kill harmful bacteria in foods such as meats, eggs and fresh produce, could be used to kill anthrax. The item in question is bombarded with electrons that kill bacteria.

When asked if use against anthrax was feasible, Clements said, "In theory, you could because radiation kills [anthrax] spores."

The company estimates that it would cost approximately one penny per letter to decontaminate mail. It added that irradiation works on everything except electronics, which could be damaged by the process.

Another company, Aramsco, is offering a decontamination service using gamma rays. It is sending out mail from clients to be irradiated by an anonymous company that normally uses the process on food.

"Anthrax is very easy to kill with irradiation," said Aramsco President Dave Naylor.

How It Works

In Titan's irradiation technology, ordinary electricity is used to create a beam of electrons. These electrons are accelerated and "shot" at the item to be sterilized. The beam that is generated is capable of penetrating the target up to a depth of 1 foot.

If the object being decontaminated is larger, X-rays can be used. The same electron beam is directed at a metal target, which generates X-rays. The X-rays are then capable of penetrating up to several feet.

Both the electron beam and the X-rays have the effect of breaking up the DNA of the bacteria almost instantly. This causes immediate death in most cases, and those bacteria that survive are incapable of multiplying.

"Whether it's a package of medical equipment, or a package of hamburger, or whether it's an envelope with anthrax in it, it kills the bacteria inside," said Titan CEO Gene Ray.

The material sent out by Aramsco is exposed to a cobalt source that generates gamma rays. Cobalt is a radioactive substance that emits gamma rays, which are high-energy waves that are often used to treat cancer, and sterilize food.

A More Familiar Form of Irradiation Might Work

Lambda Technologies in North Carolina believes that microwaves can kill the anthrax bacteria. The process would involve exposing mail to microwaves in large industrial sized machines.

These machines are not like your microwave at home. These machines use what is known as variable frequency microwave technology. This allows them to tune the machine to obtain the most efficient killing. The technology also eliminates arching, or sparks, that form when metal is put in conventional microwave ovens.

According to Howard Reisner, an immunologist at the University of North Carolina at Chapel Hill, it has been reported by several sources that microwaves can kill bacteria and bacterial spores.

Is it Safe?

Many people are concerned about safety when they hear the term irradiation. One fear is that the food itself will become radioactive. According to the Food and Drug Administration, "Irradiation does not make foods radioactive, just as an airport luggage scanner does not make luggage radioactive."

Another concern that people express is that irradiation will mutate bacteria, and create even more harmful forms. "There is no evidence that mutants that may be produced by irradiation are any more virulent than the parent microorganism; in fact, the opposite is more likely to be the case," according to the FDA.

ABC television station KGTV in San Diego contributed to this report.