## 4 Human Nutrition and Food Safety Assessment of Duckweed  
Duckweed, a common aquatic plant, has gained significant attention in recent years due to its potential as a nutrient-rich food source [95; 96]. Duckweeds have traditionally been used to prepare dishes like salads, omelettes, or vegetable curries in some South-East Asian countries (Burma, Laos, and Northern Thailand) [97], although the utilisation of duckweed in home cooking has been relatively limited [85]. It is considered to be a plant-based ingredient for future food and a sustainable alternative protein source that can replace animal meat and is healthier and more affordable [98]. When it comes to the comparative advantages of dried duckweed versus duckweed protein powder, both options hold their own merits. The dried form of duckweed may be preferable in terms of preserving the plant's full spectrum of bioactive compounds. This could be particularly beneficial for individuals seeking a more holistic, whole-food approach to nutrition. On the other hand, the duckweed protein powder offers the convenience of easy incorporation into a wide range of food products, potentially expanding its accessibility and appeal to a broader audience. Ultimately, the choice between dried duckweed and duckweed protein powder may depend on individual preferences and dietary needs. Those seeking a more comprehensive nutritional profile may gravitate towards the dried form, while those looking to boost their protein intake in a versatile manner may find the protein powder more appealing [26; 42]. The growing interest in nutrition and diet has led to a reassessment of the food value of duckweed in European countries. This shift in perspective has opened the door for the increased incorporation of duckweed into the cuisine of the EU and beyond, as chefs and home cooks alike explore the culinary versatility of this unique plant. The two main species consumed by humans are _Wolfifa arrhiza_ and _Wolfifa globosa_. Their traditional Thai name is Khai-nam, which was generally regarded as food for poor people [30]. A survey on _Wolfifa_ consumption in Thailand (Loei Province) showed that the locals still consume Wolffia in traditional ways, as an ingredient in spicy soups and salads [99]. Today, duckweed is increasingly recognised in Western diets as a sustainable alternative protein source that can replace animal meat while being healthier and more affordable [98]. Since Wolffia has a history of consumption in certain parts of the world, it is considered to be a \"traditional food from a third country\" in the European Union, falling under the novel food regulation. This means that these products should be authorised prior to marketing in the EU. During the authorisation process, the EFSA (European Food Safety Authority) and the EU member states assess the application dossier, and in the event of a positive opinion, the EU Commission authorises the marketing. Fresh plants of _Wolfifa arrhiza_ and/or _Wolfifa globosa_ have been authorised in the EU since 2021 by the Commission Implementing Regulation (EU) 2021/2191. During the authorisation procedure, the EU member states and the EFSA (European Food Safety Authority) did not submit any safety objection to the marketing of the product. In the technical report, the EFSA (European Food Safety Authority) concluded that the data submitted by the food business operator verify the safe use of the fresh plants of _Wolfifa arrhiza_ and _Wolfifa globosa_ cultivated under vertical farming conditions, which must strictly be grown in a safe, contaminant-free environment to make them suitable for human consumption [100]. However, the EFSA (European Food Safety Authority) has remarked that heavy metals and microcystins can accumulate in the culture medium; thus, the presence of these elements in the fresh plants should be controlled. Furthermore, trace elements may come from the use of fertilisers in the cultivation of Wolffia, which can be a safety concern for consumption.