5 results

Survey of Foodborne Viruses in Australian Oysters

Project number: 2013-234
Project Status:
Completed
Budget expenditure: $260,800.00
Principal Investigator: Valeria Torok
Organisation: SARDI Food Safety and Innovation
Project start/end date: 23 Feb 2014 - 22 Oct 2015
Contact:
FRDC

Need

Norovirus (NoV) is the leading cause of gastroenteritis outbreaks worldwide, and is commonly associated with shellfish. Between 2001-2010 seventeen Australian cases of suspected shellfish related NoV outbreaks were reported in OzFoodNet (Knope, 2011). More recently (March 2013) 400 people were reportedly affected by NoV following consumption of contaminated oysters from Tasmania.
Virus contamination in food poses major concerns for consumers and can impact export trade. The WHO/FAO working group (2008) on food-borne viruses, and European Food Safety Authority’s (EFSA) opinion (2011) ranked bivalves among the highest risk food groups in terms of NoV and hepatitis A virus (HAV). In 2011 the Codex Committee on Food Hygiene ratified a draft guideline on viruses in foods, with a specific annex on bivalves. It recommends that countries monitor for NoV and HAV in bivalves following high risk pollution events. Additionally, in early 2012 EFSA recommended the introduction of an acceptable NoV limit in oysters and the EU Community Reference Laboratory (2012) recommended an ‘absence’ criterion be applied for HAV in bivalves. Because of these impending international regulations (noting that some importing nations already require NoV testing), the Australian oyster industry members have indicated that they would like a more comprehensive evaluation of the prevalence of viruses in Australian oysters. There is little information on the baseline levels of NoV in Australian oysters. Although, a small pilot survey in oysters was conducted in production areas, more information is needed.
Recent developments made at SARDI in the use of molecular biology techniques for virus detection in foods would enable the occurrence of these viruses in bivalves to be determined through a virus prevalence survey. Similar surveys have been undertaken worldwide, including in the USA, UK, France and China, and might contribute to the development of market access strategies at the international level.

Objectives

1. 1 To design a statistically robust survey to evaluate virus occurrence in oyster growing areas in NSW, Qld, SA and Tas
2. 2 To identify the prevalence of NoV and HAV associated with Australian oysters at harvest
3. 3 To use the survey results to support trade and market access of Australian oysters

Assessing occurrence of pathogenic species of the marine bacteria Vibrio in Tasmanian oysters from St Helens

Project number: 2015-042
Project Status:
Completed
Budget expenditure: $29,520.38
Principal Investigator: Tom Madigan
Organisation: SARDI Food Safety and Innovation
Project start/end date: 29 Feb 2016 - 29 Jun 2016
Contact:
FRDC

Need

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.

Objectives

1. Assess for the prevalence of pathogenic Vibrio species in the St Helens harvesting region
2. Assess for the presence of genes associated with virulence in Vibrio parahaemolyticus
3. Evaluate if a relationship exisits that between prevalance and sea water temperature and salinity

Final report

ISBN: 978-1-921563-92-8
Authors: Tom Madigan Kate Wilson Gayle Smith and Alison Turnbull
Industry
PROJECT NUMBER • 2015-229
PROJECT STATUS:
COMPLETED

Oysters Australia IPA -workshop – identifying knowledge gaps for development of the native oyster aquaculture industry in South Australia

The 2015-229 “Oysters Australia IPA - workshop - identifying knowledge gaps for development of the native oyster aquaculture industry in South Australia” brought together oyster farmers, hatchery operators and scientists from across Australia to share their knowledge and experience with native...
ORGANISATION:
SARDI Food Safety and Innovation