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Seafood Safety in Maryland

Handling Seafood Safely

William Hargis Receives Mathias Medal

Two Maryland Students Become Knauss Fellows

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HACCP

In Maryland, seafood has been as safe as it can be. According to Alan Taylor of the state's Department of Health and Mental Hygiene, "the state has had no foodborne outbreak associated with its shellfish since 1939."

In spite of the facts about seafood safety, relentless reporting by print and television media over last year's Pfiesteria piscicida outbreak in Maryland sent alarms rippling through the entire Bay seafood industry. Though the fish and shellfish harvests from the Pocomoke River were reported to account for far less than one percent of the total Bay catch, supermarkets stopped carrying all Chesapeake seafood, restaurants advertised that their seafood did not come from the Bay, and the Jessup Wholesale Fishmarket, the largest on the East Coast, went into a tailspin. In fact, the organism has never been found in seafood, but only in the waters themselves.

Did the public overreact and, if so, why? How safe is the seafood that ends up at processing plants and on our tables? What protections and guarantees do we have?

Protecting Shellfish Waters

Mary Jo Garreis, long-time observer of the industry, says unequivocally that the region's seafood is safe. "The reason we've been so successful," she says, "is because there are large safety factors built in." Among those safety factors are periodic examination by the Maryland Department of Environment of shellfish for bacterial and chemical contaminants, as well as regular monitoring of shellfish waters for bacterial levels and surveying of land-borne sources of pollution, such as sewage outfalls and animal wastes.

Garreis speaks from 22 years of experience at the Maryland Department of the Environment where for much of that time she headed the Shellfish Certification Program, responsible for regulating the harvesting areas of oysters and clams.

"We are also fortunate that the industry itself is getting more and more educated," she says. "You would run into watermen 22 years ago when I first came to the Department who were totally insensitive to handling shellfish as a food product." That's rarely the case anymore. Television has had a lot do with that, she says, but also the Health Department's inspections, which not only regulate but educate. The same goes for the Maryland Watermen's Association's Gazette. "It's one of the best educational tools for reaching watermen," she says. "They read it."

In Maryland, as in all coastal states with shellfish waters, regulation is a cooperative undertaking among the state and federal government and the industry itself. Every state, working in conjunction with the federal Food and Drug Administration, oversees harvesting areas in its waters, approves them, places them off limits when pollution is consistently high, and closes them temporarily when pollution levels rise (the result of land runoff during heavy rains).

Though they have gone through changes and additions, basic regulations aimed at ensuring healthy shellfish date back to 1924, when the U.S. Public Health Service convened a conference of shellfish-producing states after outbreaks of typhoid fever in New York, Chicago and Washington, D.C. were traced to oysters polluted by sewage discharges. That meeting led to the formation of the National Shellfish Sanitation Program - in 1984, it became the Interstate Shellfish Sanitation Program (ISSP) - that set out principles for protecting public health in the harvesting and processing of shellfish.

Removing shellfish from the world of microbes is impossible. Shellfish feed by filtering solid particles from surrounding waters, including algae, microorganisms and non-living matter. Since bacteria and viruses are natural constituents of all waters, as oysters and other bivalves strain particles, they can retain large numbers of microbes.

In most cases, bacteria and viruses are neither detrimental to oysters nor to those who consume them - the mere presence of a pathogenic, or potentially disease-causing, microorganism, Garreis points out, is not sufficient to cause disease. For example, the potentially dangerous bacteria group Salmonella comes from naturally occurring sources as well as human and domestic animal wastes. Generally Salmonellae species are harmless in low numbers. At times, however, the populations of Salmonellae or other disease-causing bacteria or viruses do rise and, when they do, they can pose threats to human health, especially when shellfish are eaten raw.

Bacterial and viral counts can rise for an any number of reasons - poorly treated sewage discharges, domestic animal waste discharges and stormwater runoff from adjacent land. It is such elevated counts that the sanitary surveys and bacterial monitoring are designed to anticipate and to protect against.

How does the survey work? According to Garreis, the survey requires intensive property-by-property inspection in areas that drain to shellfish harvesting beds. "Its aim is to identify and, where possible, eliminate or minimize the sources of serious human or animal waste contamination," she says. While the ISSC recommends that the survey be done at least every twelve years, this is not often enough, says Garreis, "particularly in areas experiencing rapid development." That is why Maryland and Virginia carry out the survey every five to six years, focusing especially on the operation of waste treatment plants and septic systems and stormwater runoff from adjacent lands, a potentially serious nonpoint source of pollution.

New Regulations Promise Safe Seafood Handling

Seafood protection only begins with water quality - making sure that harvesters, processors and transporters handle fish and shellfish under sanitary conditions is critical. As of December 18, 1997, the nation's seafood industry came under new landmark regulations by the Food and Drug Administration that are designed to do just that.

Known as the HACCP (the Hazard Analysis Critical Control Point) program, it requires seafood processors - including companies that pack, process or hold seafood for shipment - to thoroughly evaluate each step of their operation as it affects product safety. Because half of the seafood consumed in the United States is imported, Food and Drug Administration inspectors will also monitor seafood importers and even inspect foreign plants that must also meet HACCP requirements.

Processors in the Chesapeake Bay have been doing a very good job of delivering quality product.

Among the seven HACCP principles, says Tom Rippen, Maryland Sea Grant Extension seafood technology specialist, are steps that require identifying critical control points where problems can occur, defining critical limits, that is, places in the process where a potential problem can be monitored and controlled, and keeping detailed records so that inspectors can easily verify that the safety program is working.

Many Maryland processors, those who voluntarily joined and helped underwrite the Maryland Seafood Quality Program, have had a head start on HACCP principles, says Rippen. Working with the Maryland Sea Grant Extension Program and the state departments of Agriculture and Natural Resources, processors assure control over bacterial pathogens by doing what the federal HACCP program requires. This means setting up safety procedures at every phase of handling, from the time crabs are off-loaded at the dock, to the steaming, picking, packing and shipping of either fresh or pasteurized product. A key element of quality assurance is the Animal Health Diagnostic laboratory at the University of Maryland, College Park, which screens seafood products through random microbiological sampling.

As a result, says Rippen, processors in the Chesapeake Bay have been doing a very good job of delivering quality product. "There has been only one suspected illness due to commercially packed seafood," he says, "and even that is not conclusive." That is not the case nationally, where the Food and Drug Administration estimates that more than 100,000 citizens are sickened by tainted seafood each year.

A key difference between HACCP and the state's Seafood Quality Program is the record keeping system that HACCP requires, and that must be open to inspection by state and federal regulators. And it is this record keeping, Rippen thinks, that will present the most difficulty for many Maryland processors because their operations are relatively small.

Nevertheless, the aim of the HACCP seafood safety program is to detect problems before they occur and not afterwards, he says, and we need to assure the public that the early warning system is working. HACCP should go a long way toward providing that assurance.

The Question of Toxin-Producing Algae and Pfiesteria

The recent appearance in the Chesapeake Bay and in North Carolina's coastal waters of Pfiesteria has raised new concerns about seafood safety.

Toxin-producing algal blooms elsewhere are not new. There are stories, for example, that Indians taught New England colonists to stop eating shellfish when the water turned red. In terms of seafood management, "we've been dealing with harmful algae in the U.S. since the 1920s," says Rippen. What appears to be changing are the number and extent of such harmful algal blooms in coastal waters. Many scientists argue that blooms are increasing world-wide, something which could cause many more problems for those responsible for guarding public health.

Resource managers in the Chesapeake Bay have not had to worry much about monitoring for toxin-producing algae. Unlike many other parts of the country, where harvesting waters are regularly shut down, particularly during warm weather, the Chesapeake Bay seafood industry has not experienced any large-scale closures due to these harmful algal blooms.

Coastal waters throughout North America - in Canada, the Gulf of Maine, the Gulf of Mexico, the Pacific Northwest - often see massive blooms of dinoflagellates or diatoms, single-celled algae that because of their pigments can turn the water red, brown, mahogany or even different hues of green. While most dinoflagellates (classified as protists) do not release harmful toxins, a small number of species do. During "blooms," periods where the densities are extremely high, toxigenic algae can harm fish and the other animals that consume them, including humans.

The health effects resulting from dinoflagellate toxins go under such names as Paralytic Shellfish Poisoning, Neurotoxic Shellfish Poisoning and Diarrhetic Shellfish Poisoning. Amnesic Shellfish Poisoning, caused by domoic acid, differs in that it is caused not by a dinoflagellate but by a diatom, a single-celled plant. Whether caused by plant or protist, taken together these illnesses can cause a range of symptoms, from gastrointestinal disorders that may last a relatively brief time to those that are potentially more serious and, in rare cases, even lethal.

The ISSC recognizes the threat posed by biotoxins and requires that states with a history of biotoxin events have special monitoring plans. State agencies in these affected regions regularly monitor for toxin-producing algae. If a bloom appears and reaches a certain density, shellfish waters - and in some cases other fishing grounds as well - are closed and only reopened when the bloom has passed and shellfish have purged the toxin.

Unlike toxins in other algae, there is no evidence that the toxin in Pfiesteria-like species remains in shellfish and finfish, including those that make it to market. There are no documented cases of anyone become sick from eating seafood taken from areas where the organism is found. Still, because of fish kills and impacts on human health that have resulted from contact with the organism in the environment, Maryland has taken a conservative approach and closed waters where Pfiesteria has been found, not only to harvesting, but to swimming and recreational fishing. A high level of public concern has spurred new federal efforts to fund research into the subject, research that will better detail the real level of risk.

New methods of detection will be essential. Traditional monitoring programs are based on identifying toxin-producing species and examining seafood for toxins. For Pfiesteria-like species, new techniques will be needed for detecting not only the organism but the toxin itself. Fortunately, research to date shows no evidence that Pfiesteria contaminates seafood, says Rippen. Indications are that the toxin is unstable, unlike many other biotoxins, and breaks down quickly.

A priority need, according to Yonathan Zohar, a molecular biologist and director of the University of Maryland Biotechnology Institute's Center of Marine Biotechnology, is encouraging the development of molecular probes that will ensure early detection. By using probes that could signal the presence of toxins, those charged with monitoring the region's waterways could detect a problem before fish die or people fall ill.

New technologies may offer the best promise for guarding against unforeseen problems as they arise. The current approach of temporarily closing areas during Pfiesteria-related fish kills will offer the public protection at least until such technologies are developed. What will remain the same is the need for continued vigilance.

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This page was last modified May 23, 2002

http://www.mdsg.umd.edu/MarineNotes/Nov-Dec97/

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