I was watching CNNs feature narrated by Zain Asher called Call to Earth,-

https://edition.cnn.com/2023/09/25/opinions/opinion-vincent-doumeizel-seaweed-scn-climate-c2e-spc-intl/index.html

putting forward ideas by Frenchman, Vincent Doumeizel. He is senior Adviser at United Nations Global Compact on Oceans and director for the Food Programme for the Lloyd’s Register Foundation. He is also guest editor of CNN’s Call to Earth series.

The programme reveals how the project pulls together food growers, researchers, cuisine explorers, and many others, to demonstrate how we might save the threatened seaweed microalgae from climate change impacts.

The highly nutritional seaweed could be cultivated in a safe and sustainable manner to create a fully nutritional food which could easily feed the world. It could also be grown in a protected environment along with other endangered species which feed on it, like certain fish and scallops.

A piece of research in 2019 explained the threats of contamination to this potential food source:

https://efsa.onlinelibrary.wiley.com/doi/full/10.2903/j.efsa.2019.e170915

The list of likely contaminants is as follows:

Abstract

During the last decade, the interest on the use of seaweed as food or feed, which was before limited to certain European regional subpopulations, has experienced a significant increase in other regions of the EU. In fact, the growing awareness and interest on sustainable and alternative food sources, healthier lifestyles and changes on dietary patterns brought seaweed to the spotlight for the general worldwide cuisine. Due to their high biosorption and accumulation capacity, seaweed can be an important source of increased exposure to persistent and potential harmful elements, such as cadmium (Cd), lead (Pb), mercury (Hg) and inorganic arsenic (iAs), or even some micronutrients, particularly iodine (I), to which an antioxidant role as been described in seaweed. This concentration potential has raised the interest of several Food Authorities regarding the risk of increased exposure to these elements. Moreover, the European Commission requested the collection of monitoring data on their levels aiming to aid the performance of better risk assessments and potentially set maximum levels on the European Legislation. This work aimed to obtain levels of these elements in species of seaweed (Fucus vesiculosus, Fucus serratus, Fucus spiralis, Fucus evanescens, Saccharina latissima, ulva lactuca and Ccladophora sp.) cultivated and harvested in Denmark, following European Commission’s request. Additionally, a collaboration between Denmark, Ireland, France and the Netherlands was initiated to review and collect all the data available on scientific papers regarding the levels of these contaminants in seaweed worldwide. The final result of this work would be the publication of a review article. This Fellowship also provided on-the-job training on the evaluation of applications of new biocides and participation in the science based advises given to the Danish Food and Veterinary Administration, Danish EPA, the Danish Medical Agency and ECHA.

1 Introduction

Up to now, mostly used by specific subpopulations in Europe (namely in Iceland, Scotland, Ireland, Wales and France) (Mahadevan, 2015; Tiwari and Troy, 2015), seaweeds or macroalgae have recently experienced and increased interest regarding their use as food and feed. In fact, after being used for centuries as a staple food particularly in Asian countries, seaweeds are expected to become a relevant food and food ingredient in the European market. Seaweeds were brought to the spotlight in the Western world due to their marketing and perception as ‘superfood’, increased interest in healthier diets and lifestyles as well as on more sustainable food sources and production (Mahadevan, 2015; Mendis and Kim, 2011; FAO, 2018). As a result, a wide variety of seaweed-based or containing products is now more easily available to European consumers, from the traditional sushi to salads, breads pasta, chips and drinks (Bouga and Combet, 2015).

With high nutritional value due to the presence of important macro- and micronutrients including vitamin B12, omega-3 and -6 fatty acids, selenium, iodine and dietary fibre (Aguilera-Morales et al., 2005; Peña-Rodríguez et al., 2011; Gil et al., 2015), seaweeds are also studied as a source of several bioactive compounds with potential health benefits/applications (Holdt and Kraan, 2011; Brown et al., 2014). Seaweeds can also be a source of increased dietary exposure to potential harmful and persistent contaminants (such as inorganic arsenic, lead,l cadmium and mercury) as well as some nutrients, such as iodine. In fact, due to the specific characteristics of their cell wall and structure, seaweeds present a high concentration potential for minerals and trace elements present in the surrounding waters. As a result, the levels of these elements are on average several orders of magnitude higher in seaweed than in the water (Jadeja and Batty, 2013; Malea et al., 2015; Bonanno and Orlando-Bonaca, 2018). This concentration potential is behind the extended use of macroalgae in biomonitoring and bioremediation protocols, from where most of the knowledge on the uptake of contaminants by seaweeds has been gathered (Hamdy, 2000; Sheng et al., 2004; Chakraborty et al., 2014; Holan et al., 1993). So far, studies report high intra- and interspecies differences, as well as geographic and seasonal variability in the concentration of different elements in macroalgae (Brito et al., 2012; Ryan et al., 2012; Chakraborty et al., 2014; Malea et al., 2015; Chen et al., 2018).

Iodine is an essential micronutrient for the synthesis of thyroid hormones, which in turn are important for growth, development and metabolism, particularly vital during earlier stages of life (WHO, 2007). Iodine can cause the dysfunction of thyroid gland at high levels of exposure. This is the reason why in 2002, EFSA’s Scientific Committee on Food (SCF) suggested a tolerable upper intake level (UL) for adults of 600 μg iodine/day and adjusted this for the remaining age groups based on differences on body surface area (body weight^0.75) (European Commission, 2002). Mercury, lead, cadmium, and inorganic arsenic are completely deprived of biological activity in humans and harmful even at trace levels (Bilal et al., 2018), being elements of greater interest for food safety authorities. Inorganic arsenic (IARC, 2012) is classified as carcinogenic for humans while methylmercury (MeHg) (IARC, 1993) and inorganic lead (IARC, 2006) have been classified as possibly carcinogenic for humans, besides being characterised by several other toxic effects in humans, e.g. neurotoxicity and nephrotoxicity.

The toxicological profile and the relative high exposure from other sources of these elements has raised the interest of several Food Authorities concerned with the exposure to excessive levels of these contaminants due to seaweed consumption (FSAI, 2015; Duinker et al., 2016; ANSES, 2018). However, maximum levels for heavy metals and metalloids have been set by the Commission Regulation No 1881/2006 (European Commission, 2006) as amended by Regulation No 629/2008 (European Commission, 2008), in a range of foodstuffs including seafood, seaweeds are not included on the list. Despite being more frequently performed, speciation of arsenic and mercury is still frequently not included despite its importance for the evaluation of the risk associated with consumption ad increase consumers’ protection. In conclusion, nowadays in Europe, there are no regulation on the maximum levels of these elements in seaweeds as food, besides a maximum limit level of 3.0 mg/kg wet weight for cadmium in ‘food supplements consisting exclusively or mainly of dried seaweed or of products derived from seaweed’ (European Commission, 2008). Recognising the emergent interest in seaweed and the lack of data on the levels of these contaminants in seaweeds available and or produced in the European market, monitoring data for the most common edible species of seaweeds have been requested by the European Commission to all member states during the period of 2018 to 2020 (European Commission, 2018). The final result of this monitoring action could be the setting of maximum levels for arsenic, lead, cadmium, mercury and iodine for seaweeds as well as providing more data to improve the risk assessments regarding the consumption of this food.

The seriousness of the food industry to cultivate and process seaweed has to address all the usual food safety standards.

At the same time, seaweed is like a canary in the mine as its cells accumulate levels of toxins which are absorbed from surrounding waters. These would be less easy to detect and analyse without having seaweed to analyse.

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Foods. 2021 Nov; 10(11): 2719. 

Published online 2021 Nov 6. doi: 10.3390/foods10112719

PMCID: PMC8619114

PMID: 34829000

Microbiological Food Safety of Seaweeds

Trond Løvdal,^1,* Bjørn Tore Lunestad,² Mette Myrmel,³ Jan Thomas Rosnes,¹ and Dagbjørn Skipnes¹

Ramón F. Moreira, Academic Editor

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Abstract

The use of seaweeds in the human diet has a long history in Asia and has now been increasing also in the western world. Concurrent with this trend, there is a corresponding increase in cultivation and harvesting for commercial production. Edible seaweed is a heterogenous product category including species within the green, red, and brown macroalgae. Moreover, the species are utilized on their own or in combinatorial food products, eaten fresh or processed by a variety of technologies. The present review summarizes available literature with respect to microbiological food safety and quality of seaweed food products, including processing and other factors controlling these parameters, and emerging trends to improve on the safety, utilization, quality, and storability of seaweeds.

Of concern is the antimicrobial resistance (AMR) in bacteria.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8619114/

Recent studies have been able to underline the value of this microalgae in a world impacted by climate change.

An interesting article

https://theconversation.com/microalgae-is-natures-green-gold-our-pioneering-project-to-feed-the-world-more-sustainably-170158

proposing a circular economy which can utilise microalgae to break down sewage waste into safe fertiliser for farmers fields; replace soya with nutritional food using microalgae; replace oil as fuel with microalgae created biofuel and so on.

Extract:

Microalgae – not to be confused with macroalgae (seaweeds) – are massively abundant in our seas, freshwater lakes and rivers. These tiny organisms are important “primary producers” on our planet, acting as biomass factories. They use sunlight through the process of photosynthesis to convert inorganic molecules (carbon dioxide, nutrients and water) into proteins, fats and carbohydrates, plus a host of other organic compounds that help them grow and survive. These tiny microorganisms support all life in our oceans and, with their high turnover rates, contribute to around 50% of the planet’s primary production.