How to store and handle seafood safely in Australia: cold-chain temperatures, histamine/scombroid prevention, live shellfish and stopping cross-contamination.
Seafood is one of the highest-risk foods you can handle. Keep it cold (at or below 5°C), preferably on ice, from delivery to service, and never let it sit in the 5–60°C danger zone. Tight temperature control also prevents histamine (scombroid) poisoning, which cooking cannot reverse. Buy shellfish only from licensed suppliers, keep raw seafood away from ready-to-eat food, and record temperatures. Requirements vary by jurisdiction, so confirm with your state or territory food regulator and local council. Key takeaways: Keep seafood at or below 5°C throughout the cold chain — ideally packed in ice — and minimise time in the 5–60°C temperature danger zone.. Histamine (scombroid) poisoning comes from temperature abuse of species like tuna, mackerel and mahi-mahi; the toxin is heat-stable and is NOT destroyed by cooking, freezing or canning.. Buy seafood — especially bivalve shellfish (oysters, mussels, pipis) — only from licensed, approved suppliers, never from recreational fishers.. Store raw seafood below and away from ready-to-eat food to prevent cross-contamination, and use dedicated boards and utensils.. You should be able to demonstrate your seafood was kept safe; under Standard 3.2.2A certain higher-risk businesses must keep temperature and supplier records — confirm what applies to you with your regulator.. Why seafood is a high-risk food Seafood spoils faster than almost any other food. Fish flesh has a near-neutral pH, high moisture and abundant free amino acids, so spoilage bacteria and, in some species, histamine-forming bacteria multiply quickly once the fish is out of tightly controlled cold storage. Bivalve molluscs (oysters, mussels, cockles, pipis) filter large volumes of water and can concentrate pathogens such as norovirus, Vibrio and marine biotoxins from their growing waters. Under the Australia New Zealand Food Standards Code, most seafood is treated as a potentially hazardous food that must generally be kept under temperature control. Fast microbial growth: spoilage and pathogenic bacteria multiply rapidly above 5°C.. Histamine risk in certain fish that cannot be reversed by cooking.. Biotoxin and pathogen concentration in filter-feeding shellfish.. Parasites (e.g. Anisakis) in some wild finfish eaten raw or lightly cured.. Natural toxins such as ciguatera in some warm-water reef fish that are unaffected by cooking or freezing.. Temperature control: the cold chain Temperature is your single most important control. Standard 3.2.2 generally requires potentially hazardous food to be kept at or below 5°C (cold) or at or above 60°C (hot), and to spend as little time as possible in the 5–60°C danger zone. Best practice for fresh fish and seafood is colder still — as close to 0°C as practical — which is why fishmongers and quality kitchens keep product bedded in ice. Check every delivery on arrival: refuse or reject seafood delivered above 5°C or showing signs of temperature abuse (soft flesh, strong ammonia/sour odour, dull sunken eyes, thawed 'fresh' product).. Store fresh fish and seafood on drained, self-draining ice in the coldest part of the coolroom; replenish ice and drain melt water so product does not sit in liquid.. Keep frozen seafood hard-frozen (typically around −18°C) and avoid partial thaw–refreeze cycles that damage quality and safety.. Thaw frozen seafood in the fridge at or below 5°C, or under cold running water — never on the bench at room temperature.. Apply the 2-hour/4-hour rule to any brief periods out of refrigeration during prep or display.. Histamine (scombroid) poisoning and how to prevent it Scombroid poisoning is caused by histamine that forms when certain fish are temperature-abused. Bacteria convert the natural amino acid histidine in the flesh into histamine. The higher the temperature and the longer the fish is warm, the more histamine forms. Crucially, histamine is heat-stable — it is not destroyed by cooking, smoking, freezing or canning — so once it has formed, the fish cannot be made safe. Prevention is entirely about keeping the fish cold from the moment it is caught. Higher-risk species belong mainly to the Scombridae and related families: tuna, mackerel, mahi-mahi (dolphinfish), sardines, anchovies, herrings, marlin, kingfish and some trevally.. The Food Standards Code sets a maximum histamine level of 200 mg/kg for fish and fish products (Schedule 19) — confirm current limits and testing expectations with FSANZ and your regulator.. Symptoms appear quickly (minutes to a few hours) and can resemble an allergic reaction: flushing, rash, headache, sweating, a peppery/metallic taste, nausea and diarrhoea.. Reject histamine-susceptible fish that has been temperature-abused even if it looks and smells acceptable — you cannot see or cook out histamine.. Move susceptible species from delivery into ice-cold storage immediately and keep handling times short and cold.. Natural toxins: ciguatera and shellfish biotoxins Some seafood hazards are natural toxins that build up in the animal before you ever receive it, and — like histamine — they cannot be reduced by cooking, freezing or cleaning. Ciguatera comes from a toxin that accumulates in certain large, warm-water reef fish (for example, some mackerel, coral trout, cod, kingfish and other reef predators, particularly larger specimens from tropical waters). It has no effect on the appearance, smell or taste of the fish. Filter-feeding bivalves can also accumulate marine biotoxins (such as those causing paralytic, diarrhetic or amnesic shellfish poisoning) from their harvest waters, which is why shellfish come from monitored, classified harvest areas. Ciguatera cannot be seen, smelled or cooked out; managing risk means sourcing carefully and being cautious with large reef fish from higher-risk tropical areas.. Follow any state or territory advice on species, sizes or areas of concern for ciguatera — guidance differs by jurisdiction.. Rely on the shellfish quality assurance system: only accept bival
How to receive and store a seafood delivery safely
Probe or surface-check the product with a clean, sanitised thermometer. Cold seafood should be at or below 5°C — ideally close to 0°C and packed in ice. Reject anything warmer or showing signs of temperature abuse.
Look for firm flesh, clear bright eyes, red gills and a clean sea smell. Reject fish with a strong ammonia or sour odour, dull sunken eyes, slimy flesh, or 'fresh' product that has clearly thawed. Check that packaging is intact and shellfish tags are present.
Verify the seafood came from a licensed, approved supplier. Keep the invoice and, for bivalve shellfish, the harvest tags or labels so the batch can be traced.
Do not leave seafood on the dock or bench. Get histamine-susceptible species and shellfish into ice-cold storage first to minimise time in the danger zone.
Bed fresh fish on self-draining ice in the coldest part of the coolroom, in sealed drip-proof containers, on the lowest shelves below ready-to-eat food. Keep frozen seafood hard-frozen.
Log the delivery temperature, time and any rejections in your temperature/records system as required by your food safety program.
Frequently asked questions
What temperature should seafood be stored at?
Keep seafood at or below 5°C to meet temperature-control requirements, but best practice is colder — as close to 0°C as practical, packed on self-draining ice. Frozen seafood should stay hard-frozen (typically around −18°C). Minimise time in the 5–60°C danger zone during delivery, prep and display, and confirm any specific rules with your local regulator.
Can you cook fish to make it safe if it wasn't kept cold?
No. Cooking kills bacteria, but it does not destroy histamine, the toxin behind scombroid poisoning in fish like tuna and mackerel. Histamine is heat-stable and survives cooking, smoking, freezing and canning. If histamine-susceptible fish has been temperature-abused, it should be rejected — you cannot make it safe by cooking it.
What is scombroid (histamine) poisoning?
Scombroid poisoning is illness caused by eating fish with high histamine levels, which form when species such as tuna, mackerel, mahi-mahi and sardines are not kept cold enough. Symptoms come on within minutes to a few hours and resemble an allergic reaction — flushing, rash, headache, sweating and a peppery taste. The prevention is strict, continuous cold storage.
Can I buy oysters or mussels from a recreational fisher for my business?
No. Bivalve shellfish must generally come from licensed, approved suppliers sourcing from classified harvest areas, so the product is traceable and monitored for pathogens and biotoxins. Buying from recreational fishers is not permitted for food businesses and removes your ability to trace or recall a batch. Keep supplier invoices and shellfish harvest tags.
How do I stop seafood contaminating other food?
Store raw seafood in sealed, drip-proof containers on the lowest shelves, below ready-to-eat and cooked food. Use dedicated cutting boards and utensils for raw seafood and clean and sanitise them before other tasks. Wash hands and surfaces after handling. Remember fish, crustacea and molluscs are separately declared allergens, so cross-contact is a labelling issue too.
How should I thaw frozen seafood safely?
Thaw frozen seafood in the fridge at or below 5°C, or under cold running water if you need it faster — never leave it on the bench at room temperature, which lets the surface enter the danger zone while the centre is still frozen. Cook thawed seafood promptly and avoid refreezing product that has partially thawed.