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Keeping diners safe as they gain a taste for seaweed

Updated: Feb 15, 2023

An expanding range of seaweed food products and ingredients is reaching our tables, and ensuring food safety is critical.

You might see seaweed foraged from the beach, or sold from boutique market stalls. It is increasingly found on supermarket shelves – in snacks, spice mixes and biscuits – or gracing the menus at high-end and eco-friendly restaurants.

Seaweeds are also integral to Asian cuisines, and that’s helping them make inroads into Australian diets, which have traditionally ignored this ocean superfood.

It’s such a new culinary adventure for Australia that many of the regulations surrounding it are still taking shape. One recent research project commissioned by AgriFutures Australia is taking a proactive approach to identify a range of potential food safety hazards for Australian consumers, and how they can be addressed.

International food safety expert Clare Winkel from Integrity Compliance Solutions has led the 'Development of a seaweed food safety program' project looking at both imported and Australian-produced seaweed food products, and at national and state food safety regulations.

Identifying hazards

Australia is a net importer of seaweed, and in 2017–18 this totalled more than 11,000 tonnes (dry weight), valued at almost AU$40 million. Of this, 2.114 tonnes, worth $34 million, was for human consumption.

There are currently only a small number of businesses producing low volumes of seaweed products in Australia as either bulk wholesale ingredients or finished retail-ready products.

Ms Winkel says as seaweed grows in popularity as a food ingredient in Australia, it is important that contamination issues do not undermine burgeoning consumer confidence in the product as a whole, which would also undermine the development of the industry locally.

Many of the hazards identified have already been well documented in other food industries, with regulations and best practices well established.

As the seaweed industry emerges in Australia, there are still significant gaps in the related food safety understanding of regulators, producers and processors.

Ms Winkel’s research is helping to help fill those gaps and includes a ‘buyers guide’ – what to look for and what questions to ask your supplier, whether you’re importing product or buying it from a local market.

As a functional food, seaweeds can provide valuable trace elements and minerals, dietary fibres and Omega-3 fatty acids. But seaweeds – or macroalgae – are as diverse as land plants, and the components that make up each species vary considerably.

Iodine levels

One of the components of greatest concern is iodine. This trace element is essential for human health, particularly for thyroid function, and many of us don’t get enough of it.

A little seaweed can help to meet dietary requirements. However, brown seaweeds including kelps can have particularly high levels of iodine and too much can be toxic.

Ms Winkel reports that excessive iodine content is the single most common reason for seaweed imports to be rejected globally, with 362 recalls or alerts between 2000–2022. In 2019 there were more than 36 seaweed-based food import recalls or alerts globally; almost half were initiated by Australia, and all were for excessive iodine.

Australian regulations allow for a maximum iodine content of 1000 milligrams per kilogram for imported brown seaweed; there is currently no standard for domestically produced seaweed.

Between January and October 2022, there were 9 seaweed products imported into Australia that were rejected for exceeding iodine limits.

These products originated from China, Japan and South Korea, and included dried kelp, dried sea vegetables, kelp powder and seasoned seaweed. (Check out the Department of Agriculture, Fisheries and Forestry’s Failing Foods Reports.)

Other countries have also rejected seaweed imports for diverse reasons. These include chemical contamination such as nitrofurans, sulphites and heavy metals, unauthorised colours, unauthorised irradiation, listeria, mould and coliforms, allergens including soy, gluten and sesame, fraudulent country of origin and species substitution.

Left: Australia is a net importer of seaweed. Photo: Catherine Norwood. Right: Food safety expert Clare Winkel. Photo supplied.


Australian risks

In Australia, in addition to high levels of iodine, known hazards for both imported and locally produced seaweeds include crustaceans and molluscs – common allergens, which may be attached to seaweeds harvested from the wild – as well as sand and other marine debris. A simple wash or blanch in fresh water provides a simple way to remove these hazards.

There is also a potential for salmonella bacteria, which can cause illness. Ms Winkel says the risk is eliminated with dried seaweeds, and where seaweed is heated (72°C for 2 minutes), for example when used in soups. However, rehydrating seaweed for raw consumption, for use in salads for instance, without heat treatment, can potentially revive any existing salmonella bacteria.

Ms Winkel's food safety analysis involved extensive consultation with those involved in Australia’s seaweed industry, including researchers, producers, processors and product suppliers, as well as state and federal government regulators.

It builds on a 2017 AgriFutures Australia report from Dr Pia Winberg, ‘Best practices for the emerging Australian Seaweed Industry: Seaweed quality control systems’.

Ms Winkel found significant differences in the regulations between government jurisdictions, in their approaches to seaweed as a food product and in their support of seaweed production as a business.

She says some jurisdictions recognise seaweed as seafood, and others don’t. Some states also support personal foraging and the wild harvesting of seaweeds by micro-businesses, while others don’t allow for this activity in any way.

As part of the project, Ms Winkel has developed safety plans for two different seaweed business models in Australia, working with industry partners PhycoHealth, and Sea Health Products, both in NSW. One is for a pond-based seaweed farm on land, the other for wild harvested seaweed.

Speaking at ISS2023

Ms Winkel will present details of her research, funded by AgriFutures Australia, at the International Seaweed Symposium which runs from February 19-24, in Hobart, Australia, and online. Her presentation on Tuesday 21 February, 2023, is part of a session on seaweed farming, harvesting and downstream processing.

Seaweed is part of the AgriFutures Australia emerging industries portfolio, and AgriFutures is a silver sponsor of ISS 2023.

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