SafeFish SEAFOOD SAFETY FACT SHEETS Assisting the industry to resolve technical trade impediments in relation to food safety and hygiene. Page 1 Contents About SafeFish 3 Amnesic Shellfish Poisons 4 Ciguatera Fish Poisoning 6 Clostridium botulinum 8 Listeria monocytogenes 9 Escherichia coli 10 Hepatitis A Virus (HAV) 12 Histamine Poisoning 14 Norovirus (NoV) 16 Okadaic Acids/Diarrhetic Shellfish Poisons 18 ABOUT SAFEFISH WHAT WE DO SafeFish provides technical advice to support SafeFish supports the resolution of issues and Paralytic Shellfish Poisons (Saxitoxins) 20 Australia’s seafood trade and market access challenges relating to the export, import and domestic Salmonella 22 negotiations and helps to resolve barriers to trade. It trade of Australian seafood products. It does this by Staphylococcus aureus 24 does this by bringing together experts in food safety undertaking the following key functions: and hygiene to work with the industry and regulators Toxic Metals 26 • Developing technical advice for trade negotiations to agree and prioritise technical issues impacting on to assist in the resolution of market access and Vibrio 28 free and fair market access for Australian seafood. food safety issues. Wax Esters 30 SafeFish has a record of success in reopening • Developing technical briefs on high priority markets and in responding quickly when issues arise. codex issues. Contact SafeFish 32 By involving all relevant parties in discussions and, • Facilitating technical attendance at high priority where necessary, commissioning additional research Codex meetings and specific working groups. to fill any knowledge gaps, an agreed Australian • Identify & facilitate research into emerging market position is reached that is technically sound and access issues. defensible. This robust process builds knowledge and relationships, and results in better outcomes • The provision of technical information and advice to support emergency incident for industry in maintaining fair market access and ensuring that the seafood they sell is safe. response management. INTRODUCTION This SafeFish resource contains a collection of informative fact sheets for a number of food safety hazards that may affect seafood in Australia. These sheets include a short summary on the hazard, its prevalence of outbreaks in Australia, the dose required to cause illness, the symptoms associated with illness, inactivation and prevention strategies, detection methods and the Australian regulatory Important Notice: Although SafeFish has taken all reasonable care in preparing this requirements for these hazards. This brochure report, neither SafeFish nor its officers accept any liability from the interpretation is also freely available on the SafeFish website or use of the information set out in this document. Information contained in this www.safefish.com.au. document is subject to change without notice. Page 3 International regulatory limits can be found in the AMNESIC SHELLFISH POISONS Trade & Market Access Database, available at www. Domoic acid (DA) is a neurotoxin produced by a group of marine microalgae known as diatoms, mostly of frdc.com.au/trade. the genus Pseudo-nitzschia. The term “amnesic shellfish poisoning (ASP)” was coined to describe domoic acid intoxication, from the observation that many of the victims of the outbreak were affected by memory MORE INFORMATION dysfunction. However, DA can cause a range of other severe neurological impacts, including chronic epilepsy, FAO 2004. Marine biotoxins. FAO Food And Nutrition and can be found in many other marine food animals, including crustaceans, tunicates, fish, mammals and Paper 80, Rome. Food and Agriculture Organization seabirds, as well as a range of gastropod and cephalopod molluscs. of the United Nations. WHAT ARE THE CAUSATIVE ORGANISMS? memories following neurological damage), Hallegraeff G. M. 2003. Algal toxins in Australian respiratory difficulty and coma. shellfish. In: Hocking, A. D. (ed.) Foodborne In Australia the known causative diatoms are from Microorganisms of Public Health Significance. Sixth the group ( WHAT CAN BE DONE TO REDUCE OR ed. New South Wales: Australian Institute of Food Pseudo-nitzschia seriata P. multiseries MANAGE THE RISK? and P. australis) and the P. delicatissima group. Science and Technology Inc. • DA is heat-stable and therefore not degraded or These species grow naturally in marine environments. Pulido, O. M. 2008. Domoic acid toxicologic destroyed by cooking, although some leaching When they are present in significant levels they may pathology: a review. :180-219 into cooking water may be expected. Marine drugs 6 cause a hazard, particularly in bivalve shellfish as US Food and Drug Administration: Fish and Fishery they are further concentrated through filter feeding. • Shellfish production in Australia requires adherence to algal biotoxin management plans Products Hazards and Controls Guidance – 4th edition WHAT OUTBREAKS HAVE OCCURRED? to control this hazard. Each state monitors 2011 http://www.fda.gov/food/guidanceregulation/ commercial shellfish areas for toxic algae in the guidancedocumentsregulatoryinformation/ The first DA outbreak occurred in Canada in 1987, water and/or toxins in the shellfish. Detection of seafood/ ucm2018426.htm when 107 people who had eaten DA-contaminated either factor above compliance levels results mussels were sickened, four of whom became in mandatory closure of fisheries until toxin comatose and subsequently died. Fourteen concentrations return to safe levels. individuals suffered long-term neurological damage. • Longer term depuration treatments may facilitate No reports of illness attributable to DA poisoning the elimination of domoic acid, but should be have been received in Australia. confirmed with chemical and/or biological testing. • Avoid consumption of crustacean tomalley Short-term mussel fishery closures have occurred (“mustard”) during bloom events as crustaceans in South Australia due to excess Pseudo-nitzschia are known to concentrate domoic acid in the counts. In 2010 a toxic Pseudo-nitzschia bloom hepatopancreas. in Wagonga Inlet on the New South Wales far south coast resulted in a four-month oyster • Public health authorities may caution or restrict harvesting closure. recreational shellfishing when waters are affected by toxic microalgal blooms. HOW MUCH DOMOIC ACID IS A HARMFUL DOSE? HOW CAN WE TEST FOR DOMOIC ACID? • Microscopy technique can be used to detect the A dose of about 1milligram of domoic acid per presence of potentially toxic diatoms in water kilogram body weight is thought capable of initiating samples. symptoms of poisoning, i.e. around 65 milligrams for • Antibody-based screening test kits or confirmatory a 65kg adult. This equates to 325 milligrams DA per chemical testing conducted by specialist kg of seafood in a 200g portion. analytical laboratories can be used to detect DA WHAT ARE THE SYMPTOMS? in seafood tissue samples. • Mild intoxication may involve only gastro-intestinal REGULATORY STANDARDS upset (nausea, vomiting, diarrhoea, gut pains). The Australian Regulatory limit for DA in bivalve • Symptoms of neuro-intoxication include molluscs is 20 milligrams per kg (http://www. headache, convulsive seizures, myoclonus foodstandards.gov.au/). State food safety regulators (involuntary, irregular muscle contractions), may apply this limit in the case of other seafood cognitive impairment and disorientation, products found to be contaminated with DA. anterograde amnesia (inability to lay down new Page 4 Page 5 WHAT CAN BE DONE TO REDUCE OR HOW CAN WE MONITOR CIGUATERA? CIGUATERA FISH POISONING MANAGE THE RISK? Ciguatera is a foodborne intoxication caused by consumption of ciguatoxins: a group of stable, fat-soluble There is currently no technology that is reliable • It’s recommended to be aware of ciguatera high chemical toxins that are found in particular fish species which spend some or most of their life-cycle on coral and cost-effective for testing fish prior to sale or risk areas and species size limits. The Sydney reefs. Precursor toxins to ciguatoxin are produced by dinoflagellate microalgae, and then modified as they consumption for ciguatoxins. Fish Market’s schedule lists fish to avoid: high move up marine food chains, for example as herbivorous fish are eaten by small carnivorous fish, which are risk species (Chinaman or Chinaman Ciguatoxins in fish can be measured by some specialist in turn eaten by larger carnivorous fish. The transformed toxins that cause illness are mainly found in large Snapper, Tripletail Maori Wrasse, Red Bass, laboratories, but the analysis is expensive and carnivorous fish. Paddle-tail or Humped-back Red Snapper therefore currently only suitable for post-intoxication and Moray Eel), and specified fish from testing or research. Individual fish suspected of WHAT OUTBREAKS HAVE OCCURRED? • Joint and/or muscle pain, lassitude. high risk areas (listed), or above specified causing ciguatera cases or outbreaks should be size limits. retained or retrieved, and forwarded to local public Ciguatera is the most common food poisoning Symptoms can last for days, weeks, months health authorities. event related to finfish consumption in Australia. or (rarely) years following a single ciguatera • Ciguatoxins are heat-stable, so are not destroyed Numerous cases and outbreaks, including some fatal poisoning incident. by cooking or freezing. REGULATORY STANDARDS intoxications, have occurred in Australia over many • Ciguatoxins are tasteless and odourless, so fresh decades.