ness in humans eating the shellfish. The exceptions are infectious hepatitis A virus and the Norwalk virus. Since viruses get into the water through sewage, testing for fecal coliform bacteria is presumed to be an adequate test to screen out virus-contaminated shellfish. But some studies have shown that this may not be so. Clem says, "We need to find ways to identify viruses in shellfish and to make sure current standards for water sanitation are adequate."

As if it weren't enough of a job dealing with contamination caused by humans, Mother Nature has a few gremlins of her own to challenge the shellfish regulators. For instance, paralytic shellfish poisoning-also called "Red Tide"-is caused by a naturally occurring marine organism. It is an age-old problem that in recent years has become newly alarming. In the past few years it seems to be increasing on the U.S. east and west coasts, requiring constant surveillance efforts and prohibition of shellfishing in affected areas. California, for instance, routinely prohibits sports-harvesting of mussels anywhere along the California coast from May 1 to Oct. 31, the time when paralytic shellfish poisoning is the greatest problem. In 1984, the ban was imposed early-on March 2-after mussels showed unusually high levels of the toxin.

Also in 1984, FDA was faced with a new problem—the appearance of a newly recognized species of disease-causing bacteria called Vibrio vulnificus, another naturally occurring organism. Epidemiologists at the Centers for Disease Control in Atlanta reported that since 1975, there have been 25 reported cases of people who suffered primary septicemia (blood poisoning) after eating raw seafood, mostly oysters. Of these, 12 died. There is evidence that Vibrio vulnificus presents a special risk to people with liver disease, such as cirrhosis or hepatitis. FDA is accelerating its research to develop methods for the rapid detection of this organism in shellfish and to find out what makes it so toxic. In the meantime, CDC has recommended that "patients with liver disease avoid raw or under-cooked seafood."

Watching over the nation's shellfish is a big job. In the United States there are over 10 million acres approved for shellfish harvesting along the Atlantic, Gulf and Pacific coasts. While FDA coordinates the regulatory efforts and provides scientific expertise, most of the legwork falls to the state health and conservation agencies.

State inspectors patrol shellfish-growing areas, keeping a special watch on those that have been closed to harvesting. They also inspect shellfish plants and harvesters and issue operating certificates to shellfish shucking, packing and repacking plants. Every package of fresh or frozen oysters, clams and mussels shipped in interstate commerce from a state-certified plant has to be marked with an identifying number preceded by an abbreviation of the state name. This number means the shellfish have been grown, processed and packaged under strict sanitary controls.

FDA, for its part, works closely with the states. The agency's nine-member shellfish field staff annually evaluates each state program, recommends corrective measures states should take to ensure safe shellfish interstate shipments, and notifies ISSC about any state program not in compliance. The agency also publishes monthly a current listing of all certified state and foreign shippers, which number about 1,500. This list is used by health agencies to ensure that restaurants and other purveyors sell only certified shellfish.

It was this federal-state liaison that led in 1981 to one of the stiffest penalties ever levied for violation of shellfishing laws. Florida's Department of Natural Resources had closed part of the Indian River to shellfish harvesting. In reviewing the state's

Cleaning Shellfish

State regulatory agencies allow shellfish from mildly polluted waters to be harvested and treated to remove pollutants, as long as proper controls are maintained. The shellfish industry makes use of two methods to cleanse shellfish of harmful bacteria and viruses. The methods are not effective against the toxin that causes paralytic shellfish poisoning, however, and shellfish may not be harvested from areas closed because of this toxin.

Relaying. Shellfish are harvested onto fishing boats or packed in bags or plastic crates and moved from contaminated waters to an approved area, usually an estuary or lagoon, that is not polluted. After two weeks, or longer, they are re-harvested. Relaying is a normal part of oyster and mussel cultivation. Many harvesters use the time when harvesting areas are closed to collect young "seed" mollusks and bring them to approved areas where they are held in rafts, trays or on ropes until maturity. This type of replanting increases harvest yields.

• Depuration. Shellfish are hosed down to remove grit and mud, placed in trays or shallow baskets, and then submerged in tanks of purified seawater. The tanks, which resemble small swimming pools, need to be located near approved estuaries because the process requires a lot of circulating clean water.

During the two days the process takes, pathogenic microorganisms are excreted in feces, which fall to the bottom of the tank. Shellfish from grossly polluted waters may not respond to depuration and therefore are not permitted to be harvested.

shellfish program, FDA's regional shellfish sanitation specialists in Atlanta concurred with this decision. One night, the Florida Marine Patrol caught and arrested three men clamming on the river. (Clamming at night in itself is against that state's law.) The state brought charges, and the men were found guilty. A Florida district court judge revoked their commercial shellfishing licenses for one year, ordered their boat confiscated, and told them not to go on Indian River for a year. Two of the men were sentenced to 45 weekends in jail and a third, spared jail because of a lung condition, was fined $1,000.

FDA also works with other countries to ensure safe shellfish. Seven countries have agreements (called Memorandums of Understanding) with FDA to abide by the NSSP standards: Canada, Japan, Republic of Korea, Iceland, Mexico, England and New Zealand.

When a problem arises, FDA shellfish specialists work with their counterparts in the foreign country to resolve it. For instance, in 1982, clams imported from England caused disease outbreaks in which several hundred people in New York became ill. FDA prohibited importation of English clams but also volunteered assistance. A representative of the English Ministry of Agriculture visited several U.S. shellfish plants and talked to FDA and state officials about sanitation procedures. In the fall of 1984, two FDA shellfish specialists went to England to evaluate their shellfish facilities and control procedures, and they made a series of recommendations. When corrections have been made-and confirmed by FDA-the import ban will be lifted. ■

Carol Ballentine is a member of FDA's communications staff.

A.

Yes, the veal industry has a high rate of antibiotic-in-feed use because of some special circumstances. That is to say, they take very young calves and either feed them out as fancy veal or fed veal or they slaughter the very young calves. Since they are taken off their mothers, if you will, so quickly, they need antibiotics to replace the natural immunities they would receive through mother's milk. So they would be in the category, I suppose, of the swine-about 80 percent.

Q.

Since other growth promoters are available for use in livestock that aren't used in human medicine, why aren't they being used more widely?

I think they are being used more

A. often than in the past. The peni

cillin and tetracycline preparations were on the market first because they were discovered first and they have not only pride of place, therefore, but they are also less expensive. So, good, economy-minded livestock producers naturally tend to use those products that will do the same job and cost a little bit less.

Q.

Some critics have charged that meat producers use antibiotics because it is easier than cleaning up the barns and the feed lots. How valid do you think that argument is?

There is evidence of that in cer

A. tain cases. I think that the way

we rear livestock in the United States today-and, I might add, in most of the rest of the world-we are always going to need drugs to be added to the feed. FDA's only position in this is that those drugs are not to include penicillin and tetracycline. But we are not in the position of wanting to ban all antibiotics in feed.

it would be less than that, probably twothirds, and with chickens, even less than that. Turkeys-about like chickens.

Q.

Veal is one of the highest, is it not?

United Kingdom penicillin and tetracycline were never banned. What they did was to put them on a prescription status so veterinarians had to be involved in prescribing them. We know that in England, therefore, the consumption of these antibiotics at high levels has continued.

'We are not in the position of vanting to ban all antibiotics n feed."

Q.

A.

So the prescription status really did not have a very big effect? It had very little effect and, as you would expect, resistant organisms are as plentiful in England now as they were prior to the imposition of the prescription status. In Holland, on the other hand, where they did ban tetracycline and did have good baseline data, they found a dramatic reversion of susceptibility, particularly in Salmonella, after limiting the use of tetracycline in animal feeds. The bacteria became less resistant to tetracycline. I think in Holland they probably saved that antibiotic. There have been similar experiences in other countries.

You must understand though that very few countries raise livestock to the extent and with the efficiency that the United States does. So the use of these antibiotics has never achieved such prominence in, for instance, the Scandinavian countries or the southern European countries. So really, they do not have anything to ban, and if they did it would not make much difference because they don't have the market penetration.

A.

made for that except for the Dutch experience. Almost as soon as they limited the use of tetracycline in animal feed, they noticed an improved situation. It would appear that with basic penicillin, we may have gone too far. It will take a long time for it to revert to form, but I think that is not only possible, but a biological expectation that all of us have who work in the field. With tetracycline I think we will see rapid improvement. I think it is probably time to go ahead and

Q.

A.

How long would it take for FDA to effect a ban on these drugs? We would not act precipitously. I think I can be safe in saying that

we would proceed to hold an administrative hearing wherein the drug industry and other supporters of these two antibiotics would be able to present scientific data-that is to say, the other side of the case. FDA also would present its side of the case, and the administrative law judge would then rule on what he thought of the situation, submit that report to the commissioner, and FDA would make the final decision. That process could take as long as three years.