Assessing occurrence of pathogenic species of the marine bacteria Vibrio in Tasmanian oysters from St Helens
This is the first time that an illness associated with Vibrio has been traced-back to Tasmanian oysters. Regrettably, this incident occurred in the only major harvesting area in Tasmania that has not been impacted by the current Pacific oyster mortality event.
In Australia the control of Vibrio is currently limited to temperature controls during storage or transport. Pre-harvest controls used by the shellfish quality assurance programs are predicated on controlling risk posed by faecal contamination and biotoxins and are not suitable for controlling risk from these naturally occurring bacteria. Although the recent implementation of the Codex Standard for pathogenic marine vibrios suggests risk in bivalve growing areas should be assessed to ascertain the risk to public health, there has been limited research undertaken in Australia. The studies undertaken to date have generally been short in nature with no comprehensive longitudinal studies being undertaken and methodologies have now progressed significantly, whereas New Zealand has been undertaking a long-term survey to understand the risk posed by these pathogens (Cruz, Hedderley & Fletcher 2015). This issue may become a risk in accessing key markets that are active in monitoring or who regulate for these pathogens.
There is an immediate need to collect information on prevalence for the remainder of the summer period to understand the risk and evaluate if there is a relationship to salinity, temperature and toxic strains. This information will be immediately useful for developing appropriate management plans in this growing region.
This illness outbreak will likely result in Tasmanian Shellfish Quality Assurance Program and the other state programs having to consider how to manage risk in the growing areas and establish what is an acceptable level. The work proposed here could be used as a framework for future work that assesses risk across the bivalve industry Australia-wide.
Final report
Seafood CRC: overseas market access for shellfish
The potential reduction of regulatory thresholds for marine biotoxins in the EU will have significant negative economic consequences for the Australian oyster, mussel, scallop and abalone industries (and pipi’s if domestic regulatory thresholds also changed).
The scallop, oyster and mussel industry currently export product to the EU. Total scallop exports to the EU in 2006/2007 were valued at around $4,551,000 AUD (187 t). Other mollusc (including oysters and mussels) exports to the EU in 2006/2007 were around $1,084,000 AUD (255 t). Due to the periodic occurrence of okadaic acid toxins and saxitoxins in Australian shellfish the implementation of reduced regulatory levels would reduce the amount of product eligible for export to the EU.
Exports of Australian abalone to the EU ceased in 2007, this was in part due to the enforcement of marine biotoxin regulatory limits by the EC. The wild caught abalone industry is attempting to regain market access to the EU through determining alternate risk management procedures for marine biotoxins in abalone. The reduction of regulatory levels for marine biotoxins may impinge on future EU access arrangements for Australian abalone.
Experience has repeatedly demonstrated that European decisions can impact on other more commercially significant markets, including Asia and the domestic market. Codex may also be prompted to change marine biotoxin guidance levels in response to EU changes. Wide spread adoption of reduced regulatory levels for marine biotoxins would result in increased growing area closures in Australia and less product eligible for sale. This proposal aims to assist in maintaining the current EU regulatory limits for marine biotoxins which will allow the current amount of shellfish to be exported to the EU and avoid other markets being influenced.
Final report
The oyster, scallop and mussel industries currently export product to the EU. Due to the periodic occurrence of Okadaic Acid (OA) and Saxitoxin (STX) group toxins in Australian shellfish the implementation of reduced regulatory levels would reduce the amount of product eligible for EU export. Exports of Australian abalone to the EU ceased in 2007, due in part to the enforcement of marine biotoxin regulatory limits set by the EC. The wild caught abalone industry is attempting to regain EU market access through determining alternate risk management procedures for marine biotoxins in abalone.
The European Commission (EC) requested the European Food Safety Authority (EFSA) to assess the current European Union (EU) limits for shellfish regarding human health and methods of analysis for various marine biotoxins, including newly emerging toxins. A critical recommendation of the ‘EFSA Opinions’ is that the regulatory limits should be significantly lower (more stringent) for both OA and STX.
The objectives of this study were to:
- Undertake a robust technical review of the EFSA risk assessments on STX and OA group toxins.
- Submit the technical review and a rationale for maintaining current marine biotoxin regulatory limits to the EC.
- Convene a working group to determine future steps required to mitigate potential lowering of marine biotoxin regulatory limits.