Depuration in the context of this report can be defined as the process by which harvested shellfish are placed in land based plants containing clean estuarine water to permit the purging of their gastrointestinal contents under controlled conditions. Depuration does not include the practice of relaying shellfish to clean estuarine waters for long periods to promote self cleansing.

Shellfish (defined as bivalve molluscs for the purpose of this review) filter large volumes of water and trap particulate matter and dissolved substances suspended in the water as a source of food. Consequently, if the water in which they are grown is polluted, then the shellfish may concentrate microbes or chemicals which may be injurious to the consumer. Because shellfish are often consumed raw (or slightly cooked) and whole (including their gastrointestinal tract), they are generally classified as a high-risk food group by health authorities worldwide.

Shellfish are depurated in order to reduce the likelihood of transmitting infectious agents to consumers. Depuration has been demonstrated to successfully reduce to low levels the number of bacterial and some viral agents in moderately polluted shellfish. The effectiveness of the depuration process is dependent on a number of variables including the health status of the shellfish, environmental parameters within the depuration plant (salinity, temperature, turbidity), the type of pathogen, and level of contamination.

Depuration has been practiced around the world since early this century. In 1978 the practice was formally introduced in NSW as a response to a food poisoning outbreak over 2000 cases of viral gastroenteritis, which was attributed to oysters farmed in the Georges River. Depuration of all oysters harvested in NSW became a statutory requirement in 1983.

After reviewing the literature and consulting industry and relevant experts, two areas of contention have been identified with the practice of depuration in NSW and perhaps elsewhere in the world. The first issue relates to operational parameters and regulation of the process, the second appears to be a simple failure by sections of industry and regulatory authorities to appreciate that depuration alone does not ensure shellfish food safety.

Keywords: depuration, shellfish, quality, viruses, bacteria, HACCP.

Depuration in the context of this report can be defined as the process by which harvested shellfish are placed in land based plants containing clean estuarine water to permit the purging of their gastrointestinal contents under controlled conditions. Depuration does not include the practice of relaying shellfish to clean estuarine waters for long periods to promote self cleansing.

Shellfish (defined as bivalve molluscs for the purpose of this review) filter large volumes of water and trap particulate matter and dissolved substances suspended in the water as a source of food. Consequently, if the water in which they are grown is polluted, then the shellfish may concentrate microbes or chemicals which may be injurious to the consumer. Because shellfish are often consumed raw (or slightly cooked) and whole (including their gastrointestinal tract), they are generally classified as a high-risk food group by health authorities worldwide.

Shellfish are depurated in order to reduce the likelihood of transmitting infectious agents to consumers. Depuration has been demonstrated to successfully reduce to low levels the number of bacterial and some viral agents in moderately polluted shellfish. The effectiveness of the depuration process is dependent on a number of variables including the health status of the shellfish, environmental parameters within the depuration plant (salinity, temperature, turbidity), the type of pathogen, and level of contamination.

Depuration has been practiced around the world since early this century. In 1978 the practice was formally introduced in NSW as a response to a food poisoning outbreak over 2000 cases of viral gastroenteritis, which was attributed to oysters farmed in the Georges River. Depuration of all oysters harvested in NSW became a statutory requirement in 1983.

After reviewing the literature and consulting industry and relevant experts, two areas of contention have been identified with the practice of depuration in NSW and perhaps elsewhere in the world. The first issue relates to operational parameters and regulation of the process, the second appears to be a simple failure by sections of industry and regulatory authorities to appreciate that depuration alone does not ensure shellfish food safety.

Keywords: depuration, shellfish, quality, viruses, bacteria, HACCP.

Depuration in the context of this report can be defined as the process by which harvested shellfish are placed in land based plants containing clean estuarine water to permit the purging of their gastrointestinal contents under controlled conditions. Depuration does not include the practice of relaying shellfish to clean estuarine waters for long periods to promote self cleansing.

Shellfish (defined as bivalve molluscs for the purpose of this review) filter large volumes of water and trap particulate matter and dissolved substances suspended in the water as a source of food. Consequently, if the water in which they are grown is polluted, then the shellfish may concentrate microbes or chemicals which may be injurious to the consumer. Because shellfish are often consumed raw (or slightly cooked) and whole (including their gastrointestinal tract), they are generally classified as a high-risk food group by health authorities worldwide.

Shellfish are depurated in order to reduce the likelihood of transmitting infectious agents to consumers. Depuration has been demonstrated to successfully reduce to low levels the number of bacterial and some viral agents in moderately polluted shellfish. The effectiveness of the depuration process is dependent on a number of variables including the health status of the shellfish, environmental parameters within the depuration plant (salinity, temperature, turbidity), the type of pathogen, and level of contamination.

Depuration has been practiced around the world since early this century. In 1978 the practice was formally introduced in NSW as a response to a food poisoning outbreak over 2000 cases of viral gastroenteritis, which was attributed to oysters farmed in the Georges River. Depuration of all oysters harvested in NSW became a statutory requirement in 1983.

After reviewing the literature and consulting industry and relevant experts, two areas of contention have been identified with the practice of depuration in NSW and perhaps elsewhere in the world. The first issue relates to operational parameters and regulation of the process, the second appears to be a simple failure by sections of industry and regulatory authorities to appreciate that depuration alone does not ensure shellfish food safety.

Keywords: depuration, shellfish, quality, viruses, bacteria, HACCP.

Depuration in the context of this report can be defined as the process by which harvested shellfish are placed in land based plants containing clean estuarine water to permit the purging of their gastrointestinal contents under controlled conditions. Depuration does not include the practice of relaying shellfish to clean estuarine waters for long periods to promote self cleansing.

Shellfish (defined as bivalve molluscs for the purpose of this review) filter large volumes of water and trap particulate matter and dissolved substances suspended in the water as a source of food. Consequently, if the water in which they are grown is polluted, then the shellfish may concentrate microbes or chemicals which may be injurious to the consumer. Because shellfish are often consumed raw (or slightly cooked) and whole (including their gastrointestinal tract), they are generally classified as a high-risk food group by health authorities worldwide.

Shellfish are depurated in order to reduce the likelihood of transmitting infectious agents to consumers. Depuration has been demonstrated to successfully reduce to low levels the number of bacterial and some viral agents in moderately polluted shellfish. The effectiveness of the depuration process is dependent on a number of variables including the health status of the shellfish, environmental parameters within the depuration plant (salinity, temperature, turbidity), the type of pathogen, and level of contamination.

Depuration has been practiced around the world since early this century. In 1978 the practice was formally introduced in NSW as a response to a food poisoning outbreak over 2000 cases of viral gastroenteritis, which was attributed to oysters farmed in the Georges River. Depuration of all oysters harvested in NSW became a statutory requirement in 1983.

After reviewing the literature and consulting industry and relevant experts, two areas of contention have been identified with the practice of depuration in NSW and perhaps elsewhere in the world. The first issue relates to operational parameters and regulation of the process, the second appears to be a simple failure by sections of industry and regulatory authorities to appreciate that depuration alone does not ensure shellfish food safety.

Keywords: depuration, shellfish, quality, viruses, bacteria, HACCP.

Depuration in the context of this report can be defined as the process by which harvested shellfish are placed in land based plants containing clean estuarine water to permit the purging of their gastrointestinal contents under controlled conditions. Depuration does not include the practice of relaying shellfish to clean estuarine waters for long periods to promote self cleansing.

Shellfish (defined as bivalve molluscs for the purpose of this review) filter large volumes of water and trap particulate matter and dissolved substances suspended in the water as a source of food. Consequently, if the water in which they are grown is polluted, then the shellfish may concentrate microbes or chemicals which may be injurious to the consumer. Because shellfish are often consumed raw (or slightly cooked) and whole (including their gastrointestinal tract), they are generally classified as a high-risk food group by health authorities worldwide.

Shellfish are depurated in order to reduce the likelihood of transmitting infectious agents to consumers. Depuration has been demonstrated to successfully reduce to low levels the number of bacterial and some viral agents in moderately polluted shellfish. The effectiveness of the depuration process is dependent on a number of variables including the health status of the shellfish, environmental parameters within the depuration plant (salinity, temperature, turbidity), the type of pathogen, and level of contamination.

Depuration has been practiced around the world since early this century. In 1978 the practice was formally introduced in NSW as a response to a food poisoning outbreak over 2000 cases of viral gastroenteritis, which was attributed to oysters farmed in the Georges River. Depuration of all oysters harvested in NSW became a statutory requirement in 1983.

After reviewing the literature and consulting industry and relevant experts, two areas of contention have been identified with the practice of depuration in NSW and perhaps elsewhere in the world. The first issue relates to operational parameters and regulation of the process, the second appears to be a simple failure by sections of industry and regulatory authorities to appreciate that depuration alone does not ensure shellfish food safety.

Keywords: depuration, shellfish, quality, viruses, bacteria, HACCP.

Depuration in the context of this report can be defined as the process by which harvested shellfish are placed in land based plants containing clean estuarine water to permit the purging of their gastrointestinal contents under controlled conditions. Depuration does not include the practice of relaying shellfish to clean estuarine waters for long periods to promote self cleansing.

Shellfish (defined as bivalve molluscs for the purpose of this review) filter large volumes of water and trap particulate matter and dissolved substances suspended in the water as a source of food. Consequently, if the water in which they are grown is polluted, then the shellfish may concentrate microbes or chemicals which may be injurious to the consumer. Because shellfish are often consumed raw (or slightly cooked) and whole (including their gastrointestinal tract), they are generally classified as a high-risk food group by health authorities worldwide.

Shellfish are depurated in order to reduce the likelihood of transmitting infectious agents to consumers. Depuration has been demonstrated to successfully reduce to low levels the number of bacterial and some viral agents in moderately polluted shellfish. The effectiveness of the depuration process is dependent on a number of variables including the health status of the shellfish, environmental parameters within the depuration plant (salinity, temperature, turbidity), the type of pathogen, and level of contamination.

Depuration has been practiced around the world since early this century. In 1978 the practice was formally introduced in NSW as a response to a food poisoning outbreak over 2000 cases of viral gastroenteritis, which was attributed to oysters farmed in the Georges River. Depuration of all oysters harvested in NSW became a statutory requirement in 1983.

After reviewing the literature and consulting industry and relevant experts, two areas of contention have been identified with the practice of depuration in NSW and perhaps elsewhere in the world. The first issue relates to operational parameters and regulation of the process, the second appears to be a simple failure by sections of industry and regulatory authorities to appreciate that depuration alone does not ensure shellfish food safety.

Keywords: depuration, shellfish, quality, viruses, bacteria, HACCP.

Depuration in the context of this report can be defined as the process by which harvested shellfish are placed in land based plants containing clean estuarine water to permit the purging of their gastrointestinal contents under controlled conditions. Depuration does not include the practice of relaying shellfish to clean estuarine waters for long periods to promote self cleansing.

Shellfish (defined as bivalve molluscs for the purpose of this review) filter large volumes of water and trap particulate matter and dissolved substances suspended in the water as a source of food. Consequently, if the water in which they are grown is polluted, then the shellfish may concentrate microbes or chemicals which may be injurious to the consumer. Because shellfish are often consumed raw (or slightly cooked) and whole (including their gastrointestinal tract), they are generally classified as a high-risk food group by health authorities worldwide.

Shellfish are depurated in order to reduce the likelihood of transmitting infectious agents to consumers. Depuration has been demonstrated to successfully reduce to low levels the number of bacterial and some viral agents in moderately polluted shellfish. The effectiveness of the depuration process is dependent on a number of variables including the health status of the shellfish, environmental parameters within the depuration plant (salinity, temperature, turbidity), the type of pathogen, and level of contamination.

Depuration has been practiced around the world since early this century. In 1978 the practice was formally introduced in NSW as a response to a food poisoning outbreak over 2000 cases of viral gastroenteritis, which was attributed to oysters farmed in the Georges River. Depuration of all oysters harvested in NSW became a statutory requirement in 1983.

After reviewing the literature and consulting industry and relevant experts, two areas of contention have been identified with the practice of depuration in NSW and perhaps elsewhere in the world. The first issue relates to operational parameters and regulation of the process, the second appears to be a simple failure by sections of industry and regulatory authorities to appreciate that depuration alone does not ensure shellfish food safety.

Keywords: depuration, shellfish, quality, viruses, bacteria, HACCP.

Depuration in the context of this report can be defined as the process by which harvested shellfish are placed in land based plants containing clean estuarine water to permit the purging of their gastrointestinal contents under controlled conditions. Depuration does not include the practice of relaying shellfish to clean estuarine waters for long periods to promote self cleansing.

Shellfish (defined as bivalve molluscs for the purpose of this review) filter large volumes of water and trap particulate matter and dissolved substances suspended in the water as a source of food. Consequently, if the water in which they are grown is polluted, then the shellfish may concentrate microbes or chemicals which may be injurious to the consumer. Because shellfish are often consumed raw (or slightly cooked) and whole (including their gastrointestinal tract), they are generally classified as a high-risk food group by health authorities worldwide.

Shellfish are depurated in order to reduce the likelihood of transmitting infectious agents to consumers. Depuration has been demonstrated to successfully reduce to low levels the number of bacterial and some viral agents in moderately polluted shellfish. The effectiveness of the depuration process is dependent on a number of variables including the health status of the shellfish, environmental parameters within the depuration plant (salinity, temperature, turbidity), the type of pathogen, and level of contamination.

Depuration has been practiced around the world since early this century. In 1978 the practice was formally introduced in NSW as a response to a food poisoning outbreak over 2000 cases of viral gastroenteritis, which was attributed to oysters farmed in the Georges River. Depuration of all oysters harvested in NSW became a statutory requirement in 1983.

After reviewing the literature and consulting industry and relevant experts, two areas of contention have been identified with the practice of depuration in NSW and perhaps elsewhere in the world. The first issue relates to operational parameters and regulation of the process, the second appears to be a simple failure by sections of industry and regulatory authorities to appreciate that depuration alone does not ensure shellfish food safety.

Keywords: depuration, shellfish, quality, viruses, bacteria, HACCP.

Depuration in the context of this report can be defined as the process by which harvested shellfish are placed in land based plants containing clean estuarine water to permit the purging of their gastrointestinal contents under controlled conditions. Depuration does not include the practice of relaying shellfish to clean estuarine waters for long periods to promote self cleansing.

Shellfish (defined as bivalve molluscs for the purpose of this review) filter large volumes of water and trap particulate matter and dissolved substances suspended in the water as a source of food. Consequently, if the water in which they are grown is polluted, then the shellfish may concentrate microbes or chemicals which may be injurious to the consumer. Because shellfish are often consumed raw (or slightly cooked) and whole (including their gastrointestinal tract), they are generally classified as a high-risk food group by health authorities worldwide.

Shellfish are depurated in order to reduce the likelihood of transmitting infectious agents to consumers. Depuration has been demonstrated to successfully reduce to low levels the number of bacterial and some viral agents in moderately polluted shellfish. The effectiveness of the depuration process is dependent on a number of variables including the health status of the shellfish, environmental parameters within the depuration plant (salinity, temperature, turbidity), the type of pathogen, and level of contamination.

Depuration has been practiced around the world since early this century. In 1978 the practice was formally introduced in NSW as a response to a food poisoning outbreak over 2000 cases of viral gastroenteritis, which was attributed to oysters farmed in the Georges River. Depuration of all oysters harvested in NSW became a statutory requirement in 1983.

After reviewing the literature and consulting industry and relevant experts, two areas of contention have been identified with the practice of depuration in NSW and perhaps elsewhere in the world. The first issue relates to operational parameters and regulation of the process, the second appears to be a simple failure by sections of industry and regulatory authorities to appreciate that depuration alone does not ensure shellfish food safety.

Keywords: depuration, shellfish, quality, viruses, bacteria, HACCP.

Depuration in the context of this report can be defined as the process by which harvested shellfish are placed in land based plants containing clean estuarine water to permit the purging of their gastrointestinal contents under controlled conditions. Depuration does not include the practice of relaying shellfish to clean estuarine waters for long periods to promote self cleansing.

Shellfish (defined as bivalve molluscs for the purpose of this review) filter large volumes of water and trap particulate matter and dissolved substances suspended in the water as a source of food. Consequently, if the water in which they are grown is polluted, then the shellfish may concentrate microbes or chemicals which may be injurious to the consumer. Because shellfish are often consumed raw (or slightly cooked) and whole (including their gastrointestinal tract), they are generally classified as a high-risk food group by health authorities worldwide.

Shellfish are depurated in order to reduce the likelihood of transmitting infectious agents to consumers. Depuration has been demonstrated to successfully reduce to low levels the number of bacterial and some viral agents in moderately polluted shellfish. The effectiveness of the depuration process is dependent on a number of variables including the health status of the shellfish, environmental parameters within the depuration plant (salinity, temperature, turbidity), the type of pathogen, and level of contamination.

Depuration has been practiced around the world since early this century. In 1978 the practice was formally introduced in NSW as a response to a food poisoning outbreak over 2000 cases of viral gastroenteritis, which was attributed to oysters farmed in the Georges River. Depuration of all oysters harvested in NSW became a statutory requirement in 1983.

After reviewing the literature and consulting industry and relevant experts, two areas of contention have been identified with the practice of depuration in NSW and perhaps elsewhere in the world. The first issue relates to operational parameters and regulation of the process, the second appears to be a simple failure by sections of industry and regulatory authorities to appreciate that depuration alone does not ensure shellfish food safety.

Keywords: depuration, shellfish, quality, viruses, bacteria, HACCP.

Depuration in the context of this report can be defined as the process by which harvested shellfish are placed in land based plants containing clean estuarine water to permit the purging of their gastrointestinal contents under controlled conditions. Depuration does not include the practice of relaying shellfish to clean estuarine waters for long periods to promote self cleansing.

Shellfish (defined as bivalve molluscs for the purpose of this review) filter large volumes of water and trap particulate matter and dissolved substances suspended in the water as a source of food. Consequently, if the water in which they are grown is polluted, then the shellfish may concentrate microbes or chemicals which may be injurious to the consumer. Because shellfish are often consumed raw (or slightly cooked) and whole (including their gastrointestinal tract), they are generally classified as a high-risk food group by health authorities worldwide.

Shellfish are depurated in order to reduce the likelihood of transmitting infectious agents to consumers. Depuration has been demonstrated to successfully reduce to low levels the number of bacterial and some viral agents in moderately polluted shellfish. The effectiveness of the depuration process is dependent on a number of variables including the health status of the shellfish, environmental parameters within the depuration plant (salinity, temperature, turbidity), the type of pathogen, and level of contamination.

Depuration has been practiced around the world since early this century. In 1978 the practice was formally introduced in NSW as a response to a food poisoning outbreak over 2000 cases of viral gastroenteritis, which was attributed to oysters farmed in the Georges River. Depuration of all oysters harvested in NSW became a statutory requirement in 1983.

After reviewing the literature and consulting industry and relevant experts, two areas of contention have been identified with the practice of depuration in NSW and perhaps elsewhere in the world. The first issue relates to operational parameters and regulation of the process, the second appears to be a simple failure by sections of industry and regulatory authorities to appreciate that depuration alone does not ensure shellfish food safety.

Keywords: depuration, shellfish, quality, viruses, bacteria, HACCP.

Depuration in the context of this report can be defined as the process by which harvested shellfish are placed in land based plants containing clean estuarine water to permit the purging of their gastrointestinal contents under controlled conditions. Depuration does not include the practice of relaying shellfish to clean estuarine waters for long periods to promote self cleansing.

Shellfish (defined as bivalve molluscs for the purpose of this review) filter large volumes of water and trap particulate matter and dissolved substances suspended in the water as a source of food. Consequently, if the water in which they are grown is polluted, then the shellfish may concentrate microbes or chemicals which may be injurious to the consumer. Because shellfish are often consumed raw (or slightly cooked) and whole (including their gastrointestinal tract), they are generally classified as a high-risk food group by health authorities worldwide.

Shellfish are depurated in order to reduce the likelihood of transmitting infectious agents to consumers. Depuration has been demonstrated to successfully reduce to low levels the number of bacterial and some viral agents in moderately polluted shellfish. The effectiveness of the depuration process is dependent on a number of variables including the health status of the shellfish, environmental parameters within the depuration plant (salinity, temperature, turbidity), the type of pathogen, and level of contamination.

Depuration has been practiced around the world since early this century. In 1978 the practice was formally introduced in NSW as a response to a food poisoning outbreak over 2000 cases of viral gastroenteritis, which was attributed to oysters farmed in the Georges River. Depuration of all oysters harvested in NSW became a statutory requirement in 1983.

After reviewing the literature and consulting industry and relevant experts, two areas of contention have been identified with the practice of depuration in NSW and perhaps elsewhere in the world. The first issue relates to operational parameters and regulation of the process, the second appears to be a simple failure by sections of industry and regulatory authorities to appreciate that depuration alone does not ensure shellfish food safety.

Keywords: depuration, shellfish, quality, viruses, bacteria, HACCP.

Depuration in the context of this report can be defined as the process by which harvested shellfish are placed in land based plants containing clean estuarine water to permit the purging of their gastrointestinal contents under controlled conditions. Depuration does not include the practice of relaying shellfish to clean estuarine waters for long periods to promote self cleansing.

Shellfish (defined as bivalve molluscs for the purpose of this review) filter large volumes of water and trap particulate matter and dissolved substances suspended in the water as a source of food. Consequently, if the water in which they are grown is polluted, then the shellfish may concentrate microbes or chemicals which may be injurious to the consumer. Because shellfish are often consumed raw (or slightly cooked) and whole (including their gastrointestinal tract), they are generally classified as a high-risk food group by health authorities worldwide.

Shellfish are depurated in order to reduce the likelihood of transmitting infectious agents to consumers. Depuration has been demonstrated to successfully reduce to low levels the number of bacterial and some viral agents in moderately polluted shellfish. The effectiveness of the depuration process is dependent on a number of variables including the health status of the shellfish, environmental parameters within the depuration plant (salinity, temperature, turbidity), the type of pathogen, and level of contamination.

Depuration has been practiced around the world since early this century. In 1978 the practice was formally introduced in NSW as a response to a food poisoning outbreak over 2000 cases of viral gastroenteritis, which was attributed to oysters farmed in the Georges River. Depuration of all oysters harvested in NSW became a statutory requirement in 1983.

After reviewing the literature and consulting industry and relevant experts, two areas of contention have been identified with the practice of depuration in NSW and perhaps elsewhere in the world. The first issue relates to operational parameters and regulation of the process, the second appears to be a simple failure by sections of industry and regulatory authorities to appreciate that depuration alone does not ensure shellfish food safety.

Keywords: depuration, shellfish, quality, viruses, bacteria, HACCP.

Depuration in the context of this report can be defined as the process by which harvested shellfish are placed in land based plants containing clean estuarine water to permit the purging of their gastrointestinal contents under controlled conditions. Depuration does not include the practice of relaying shellfish to clean estuarine waters for long periods to promote self cleansing.

Shellfish (defined as bivalve molluscs for the purpose of this review) filter large volumes of water and trap particulate matter and dissolved substances suspended in the water as a source of food. Consequently, if the water in which they are grown is polluted, then the shellfish may concentrate microbes or chemicals which may be injurious to the consumer. Because shellfish are often consumed raw (or slightly cooked) and whole (including their gastrointestinal tract), they are generally classified as a high-risk food group by health authorities worldwide.

Shellfish are depurated in order to reduce the likelihood of transmitting infectious agents to consumers. Depuration has been demonstrated to successfully reduce to low levels the number of bacterial and some viral agents in moderately polluted shellfish. The effectiveness of the depuration process is dependent on a number of variables including the health status of the shellfish, environmental parameters within the depuration plant (salinity, temperature, turbidity), the type of pathogen, and level of contamination.

Depuration has been practiced around the world since early this century. In 1978 the practice was formally introduced in NSW as a response to a food poisoning outbreak over 2000 cases of viral gastroenteritis, which was attributed to oysters farmed in the Georges River. Depuration of all oysters harvested in NSW became a statutory requirement in 1983.

After reviewing the literature and consulting industry and relevant experts, two areas of contention have been identified with the practice of depuration in NSW and perhaps elsewhere in the world. The first issue relates to operational parameters and regulation of the process, the second appears to be a simple failure by sections of industry and regulatory authorities to appreciate that depuration alone does not ensure shellfish food safety.

Keywords: depuration, shellfish, quality, viruses, bacteria, HACCP.

Depuration in the context of this report can be defined as the process by which harvested shellfish are placed in land based plants containing clean estuarine water to permit the purging of their gastrointestinal contents under controlled conditions. Depuration does not include the practice of relaying shellfish to clean estuarine waters for long periods to promote self cleansing.

Shellfish (defined as bivalve molluscs for the purpose of this review) filter large volumes of water and trap particulate matter and dissolved substances suspended in the water as a source of food. Consequently, if the water in which they are grown is polluted, then the shellfish may concentrate microbes or chemicals which may be injurious to the consumer. Because shellfish are often consumed raw (or slightly cooked) and whole (including their gastrointestinal tract), they are generally classified as a high-risk food group by health authorities worldwide.

Shellfish are depurated in order to reduce the likelihood of transmitting infectious agents to consumers. Depuration has been demonstrated to successfully reduce to low levels the number of bacterial and some viral agents in moderately polluted shellfish. The effectiveness of the depuration process is dependent on a number of variables including the health status of the shellfish, environmental parameters within the depuration plant (salinity, temperature, turbidity), the type of pathogen, and level of contamination.

Depuration has been practiced around the world since early this century. In 1978 the practice was formally introduced in NSW as a response to a food poisoning outbreak over 2000 cases of viral gastroenteritis, which was attributed to oysters farmed in the Georges River. Depuration of all oysters harvested in NSW became a statutory requirement in 1983.

After reviewing the literature and consulting industry and relevant experts, two areas of contention have been identified with the practice of depuration in NSW and perhaps elsewhere in the world. The first issue relates to operational parameters and regulation of the process, the second appears to be a simple failure by sections of industry and regulatory authorities to appreciate that depuration alone does not ensure shellfish food safety.

Keywords: depuration, shellfish, quality, viruses, bacteria, HACCP.

Depuration in the context of this report can be defined as the process by which harvested shellfish are placed in land based plants containing clean estuarine water to permit the purging of their gastrointestinal contents under controlled conditions. Depuration does not include the practice of relaying shellfish to clean estuarine waters for long periods to promote self cleansing.

Shellfish (defined as bivalve molluscs for the purpose of this review) filter large volumes of water and trap particulate matter and dissolved substances suspended in the water as a source of food. Consequently, if the water in which they are grown is polluted, then the shellfish may concentrate microbes or chemicals which may be injurious to the consumer. Because shellfish are often consumed raw (or slightly cooked) and whole (including their gastrointestinal tract), they are generally classified as a high-risk food group by health authorities worldwide.

Shellfish are depurated in order to reduce the likelihood of transmitting infectious agents to consumers. Depuration has been demonstrated to successfully reduce to low levels the number of bacterial and some viral agents in moderately polluted shellfish. The effectiveness of the depuration process is dependent on a number of variables including the health status of the shellfish, environmental parameters within the depuration plant (salinity, temperature, turbidity), the type of pathogen, and level of contamination.

Depuration has been practiced around the world since early this century. In 1978 the practice was formally introduced in NSW as a response to a food poisoning outbreak over 2000 cases of viral gastroenteritis, which was attributed to oysters farmed in the Georges River. Depuration of all oysters harvested in NSW became a statutory requirement in 1983.

After reviewing the literature and consulting industry and relevant experts, two areas of contention have been identified with the practice of depuration in NSW and perhaps elsewhere in the world. The first issue relates to operational parameters and regulation of the process, the second appears to be a simple failure by sections of industry and regulatory authorities to appreciate that depuration alone does not ensure shellfish food safety.

Keywords: depuration, shellfish, quality, viruses, bacteria, HACCP.