Shellfish Safety in Canada

The Canadian Shellfish Sanitation Program (CSSP) is a comprehensive program which ensures the safety of shellfish in Canada for consumers. The designation of safe growing waters, harvesting and shipping activites, and the processing of shellfish are highly regulated. Canada boasts one of the most comprehensive shellfish sanitation and inspection programs in the world. The industry has many procedures and guidelines in place to make it a consistently safe and wholesome resource, delivering quality and safety to shellfish consumers. Consumers are highly averse to the risk of poor quality or unsafe shellfish seafood. The assurance that farmed shellfish are safe to eat and are of high quality are the two main considerations of the shellfish culture industry.

Quality Assurance and Quality Control of Farmed Shellfish Products

Quality Assurance provides security to the end-user that the product is wholesome, meets high quality standards and is safe for consumption. To attain product Quality Assurance of Canadian shellfish, high measures of Quality Control techniques and verification processes are implemented at the plant and farm level. Shellfish growers in Canada are committed to ensuring that Quality Assurance and Quality Control (QA/QC) are principal components in their farming of shellfish.

Importance of Growing Water Quality

Bivalve shellfish (those shellfish with two matching shell halves, such as clams, oysters, mussels and scallops) exist in the water column as filter-feeders. This type of feeding invloves the shellfish filtering out of the water any particles which are the right size, disregarding whether the particles are dead or alive, good or bad. Due to the fact that bivalve shellfish are largely indiscriminate, immobile filter-feeders, they tend to reflect the chemical and biological quality of the growing water in which they live. Even low levels of bacteria present in the shellfish can quickly multiply if the product is mishandled, producing serious contamination levels. Therefore, it is very important that Canadian shellfish come from monitored and approved water sources. When the criteria for shellfish growing waters is met, the rest of the job becomes a matter of simply protecting a first-rate product from deterioration.

Pollution Sources

Environment Canada and the Canadian Food Inspection Agency monitor for the presence of contaminants in growing waters. Through their monitoring program they assure Canadians that shellfish come from pristine growing waters. The sources of contamination which can affect shellfish, and for which they are monitored, include the following:

Pollution types which are investigated include, metals, chlorinated organic compounds, petroleum products, and other organic compounds. Pollutants are monitored due to their potential to cause acute health effects, and delayed or chronic illness that may result from repeated ingestion of minute amounts. Several organic and heavy metal pollutants are persistent in shellstock tissues and may accumulate over time. Once contaminated, these animals, for all practical purposes, may never become adequately purified for safe consumption. Due to the sensitivity of shellfish to pollution and the potential for terrible consequences for shellfish farmers, the shellfish growing industry is focused on maintaining and promoting a clean environment with pristine water sources.

Oil spills, marine traffic, contaminated runoff, new commercial or residential developments, industrial expansion and illegal dumping are examples of events that are monitored by the wary grower. In addition, growers must exercise constant vigilance to avoid inadvertent contamination of shellstock during normal farm activities. Care is taken any time fuels, solvents, disinfectants, paints, stains, wood preservatives or other potential pollutants must be used, in order to prevent spills or discharges that could come into contact with shellstock or overlying waters. With careful monitoring of these pollution sources, Canadian shellfish can be guaranteed to come from clean growing waters, preventing potential public health hazards.

Potential Public Health Hazards

The goal of the Canadian Shellfish Sanitation Program is to reduce the risk of public health hazards from the consumption of contaminated shellfish. These potential hazards are described below.

Human diseases, including cholera, typhoid fever, hepatitis, polio, gastrointestinal (stomach) diseases, and others, are spread by the ingestion of water or food that is contaminated with human faecal material, or occasionally, the faeces of other warm-blooded animals. Shellfish that grow in proximity to sewage outfalls, marinas, or residences with poor sewage systems may accumulate, through their filter-feeding, viruses and bacteria that can cause human diseases. Other sources of bacterial or viral contamination are seal haul-outs, bird roosting areas and livestock.

In the late 1980s, it was recognized that a significant amount of shellfish-related gastroenteritis may be due to viruses, particularly  Norwalk virus, and that most bacterial infections of recent years are probably due to vibrios (primarily Vibrio cholerae, V. parahaemolyticus and V. vulnificus). The shift in the causative agents of shellfish-borne disease probably reflects improvements in sewage systems and general sanitation, along with large increases in coastal human populations. Typhus and hepatitis are now rare, supplanted by vibrios and viruses.

The shellfish-borne disease derived from brackish water, named Aeromonas hydrophila bacteria is now being considered a hazard. This recently discovered disease is thought to cause gastroenteritis in humans by the consumption of contaminated shellfish. This bacteria is not usually pathogenic to the general public, but it can be harmful to people with immature or compromised immune systems (ie. infants, the elderly, persons with HIV/AIDS or liver disease).

Most disease organisms that accumulate in these filter-feeding animals can be destroyed by thorough cooking. Yet, the trend of shellfish seafood preparation is that shellfish are usually eaten raw or just lightly cooked. These methods will not allow for the harmful bacteria to become inactivated. In addition, several bacteria groups produce toxins that are only very slowly degraded by cooking, causing heavily contaminated shellfish to remain unsafe to eat. Ensuring quality and safety of the shellfish which are produced is of utmost importance to shellfish farms.

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