The potential for algae to become a widely consumed substitute for conventional protein sources in Europe is limited due to several constraints. These include:

• food safety concerns,
• a lack of consumer awareness regarding the environmental benefits of consuming algae,
• and aversion towards the taste, texture, odour and colour of some algae-based foods,[1] although seaweed added to food formulations has been found to have beneficial effects on consumer response.[2]

Safety is a particular concern for microalgae due to the presence of heavy metals and toxins, which can result from the growing substrate used. As far as iodine is concerned, it is generally acknowledged that iodine deficiency is a bigger issue in the EU than overexposure.[3]

Microalgae may also expose consumers to bacterial and viral infections. The minimal use of heat in microalgae processing requires that alternative strategies are found to make the product safe for consumption.[4] 

Their allergenicity is considered low.[5] Consumer acceptance is another significant hurdle for developing the market of algae as food in Europe, as European consumers being less accustomed to the odour, appearance or umami taste of algae than, for example, Asian consumers.