4 results

Review of shellfish purification technology research and development

Project number: 1996-355
Project Status:
Completed
Budget expenditure: $23,216.00
Principal Investigator: Kerry Jackson
Organisation: Department of Primary Industries and Regional Development (NSW)
Project start/end date: 31 Dec 1996 - 11 Aug 1999
Contact:
FRDC

Need

The NSW oyster industry and the Australian shellfish industry at large can ill afford further food poisoning episodes either from seage borne viral contamination or potential deaths from organisms such vibro vulnificus. Other diseases such as hepatitis A and salmonellaosis can also pose a continuing underlying risk to growers and consumers of shellfish. As urban development continues along the NSW coast there is also a concomitant increase in proposals for sewage treatment plants to discharge treated effluent into rivers and clear STP performance standards, guidelines and recommendations from a shellfish farming perspective are needed.

The development of a broader understanding of the limitations of purification and the possible development of technology to enhance and render the current purification process a more active technique, which does more than just rely on the shellfish to "self clean" would make an important contribution to public health as well as the the image, confidence and ultimate financial well being of the industry.

Current purification techniques alone are now seen to be incomplete in ensuring that oysters are safe for human consumption, especially in regard to viral infection. It is now recognised that the current UV purification process has to be linked to water quality monitoring at the time of harvest and monitoring at the time of harvest and monitoring of meat samples. However, there has been considerable work done around the world related to R&D in purification technology since the legislation was first introduced in NSW. A number of purification related R&D project proposals have been referred to the NSW Oyster Research Advisory Committee for support for funding by the FRDC. Although the NSW Shellfish Quality Assurance Committee does not believe that there is likely to be a "one step cure all", in purification technology, an appraisal of the current state of play, the practical limitations of purification and recommendations on areas worth pursuing in shellfish purification technology development by a suitably qualified consultant is timely if not overdue. The form of this investigation would be a desk top review and such a review has potential application for emerging shellfish farming industries in other states. This review was identified as one of the urgent priorities in the recently completed NSW Oyster Industry R&D Strategic Plan.

Objectives

1. To conduct a desktop review of R&D in shellfish purification technology that is pertinent to the NSW oyster industry and the aims and objectives of the NSW Shellfish Quality Assurance Committee.
2. Provide advice to industry, the NSW Shell fish Quality Assurance Committee and the Oyster Research Advisory Committee on the status of shellfish purification R&D to enable industry to make decisions on future directions in purification technology investments and identify areas requiring further R&D in purification.
3. Provide a summary of the current "state of the art" and limitations in purification technology and R&D accomplishments to date.
4. Identify promising and likely future directions in matters relating to purification, particularly in terms of efficacy and issues such as viruses and biotoxins and usefulness of rapid detection techniques.

Final report

Author: Kerry Jackson
Final Report • 1999-01-28 • 27.04 MB
1996-355-DLD.pdf

Summary

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.

Environment
PROJECT NUMBER • 2004-084
PROJECT STATUS:
COMPLETED

Aquatic Animal Health Subprogram: investigating and managing the Perkinsus related mortality of blacklip abalone in NSW - phase 1

Since the early 1990’s, a significant proportion of blacklip abalone (Haliotis rubra) along approximately 500 km of the NSW coastline between Port Stephens and Jervis Bay have died. Sporadic histological examination of moribund abalone since 1992 and a survey of infection prevalence in abalone...
ORGANISATION:
Department of Primary Industries and Regional Development (NSW)

Seafood CRC: Sydney rock oysters: overcoming constraints to commercial scale hatchery and nursery production

Project number: 2003-209
Project Status:
Completed
Budget expenditure: $664,640.24
Principal Investigator: Wayne O'Connor
Organisation: Department of Primary Industries and Regional Development (NSW)
Project start/end date: 29 Jun 2003 - 5 Sep 2008
Contact:
FRDC

Need

A systematic program of research and development is needed to enable reliable cost-effective hatchery production of Sydney rock oyster (SRO) seed to allow demonstrated benefits of triploid oysters and advances in SRO selection for growth and disease resistance. This R&D program incorporates relevant recommendations of the recent “Review of Hatchery Production Technology and Breeding Program for Sydney Rock Oysters (“Benzie et al., FRDC 2001/213). This review acknowledged that the potential benefits of solving SRO hatchery production problems far outweigh the likely costs. The R&D program also incorporates and integrates recommendations the of the NSW Fisheries – FRDC “Sydney Rock Oyster Hatchery and Nursery Health Workshop” held on the 8 th and 9th of August 2002 at Nelson Bay. Central among these recommendations were:
1 The need for a revision of hatchery procedures and the assessment/adoption of alternate algal, larval and spat rearing technology.
2 The need to elucidate the fundamental autecological (temperature and salinity) and nutritional requirements of SRO during early ontogeny, that have not yet been addressed and will be central to the production of the species.
3 The need for systematic and appropriate sampling procedures for the diagnosis of potential disease occurrences.

Independent of the species involved, there is a need to document the processes involved in developing techniques and strategies to culture otherwise intransigent species. This research will provide a unique opportunity to document the history of problems with SRO, the consultation undertaken, the strategies developed for SRO and the techniques for their implementation. This document, the FRDC final report for this research, would provide a reference for dealing systematically with hatchery based problems and will provide an array of monitoring and assessment protocols for other molluscs.

Objectives

1. To establish protocols for improved broodstock conditioning and handling, particularly to permit out-of-season spawning of selected oyster stocks.
2. To determine the effects of the key autecological factors (temperature and salinity) and nutrition on SRO embryos and larvae, to evaluate early larval survival and late larval growth in commercial hatcheries.
3. To trial economical, low cost alternative techniques for algal and larval and spat rearing to enhance commercial SRO production. In particular to establish alternative approaches for spat rearing including spat bubblers and field based nursery systems.
4. To systematically assess the major potential pathogenic or toxic factors that might contribute to larval and spat mortality.
5. To facilitate the establishment of a reliable commercial source of genetically improved SRO spat.

Final report

Author: Wayne O'Connor
Final Report • 2009-09-28 • 1.79 MB
2003-209-DLD.pdf

Summary

Objectives:

  • 1. To establish protocols for improved broodstock conditioning and handling, particularly to permit out-of-season spawning of selected oyster stocks.
  • 2. To determine the effects of the key autecological factors (temperature and salinity) and nutrition on SRO embryos and larvae, to elevate early larval survival and late larval growth in commercial hatcheries.
  • 3. To trial economical, low cost alternative techniques for algal and larval and spat rearing to enhance commercial SRO production. In particular to establish alternative approaches for spat rearing including spat bubblers and field based nursery systems.
  • 4. To systematically assess and monitor the major potential pathogenic factors that might contribute to spat mortality.
  • 5. To facilitate the establishment of a reliable commercial source of genetically improved SRO spat.
  • As a function of the early success of this program in overcoming hatchery production problems, two additional milestones were added with the objective:

  • 6. To assess the performance of selectively bred oysters at seven sites across NSW and then monitor the changes in physiological and reproductive condition of those oysters at 3 of those sites.
  • Environment
    PROJECT NUMBER • 1992-079
    PROJECT STATUS:
    COMPLETED

    Effects of Trawling Subprogram: the interaction between fish trawling and other commercial and recreational fisheries

    There is worldwide concern over the potential effects of by-catch and discarding of fish in commercial fisheries, particularly trawling. Although mortalities of discards are highly variable, it is likely that a large proportion of fish discarded at sea by trawlers do not survive. Consequently,...
    ORGANISATION:
    Department of Primary Industries and Regional Development (NSW)
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