UC study evaluates the presence of viruses and bacteria in macroalgae and halophytes on the west coast of mainland Portugal

A team of researchers from the Faculty of Sciences and Technology of the University of Coimbra (FCTUC), in collaboration with the Faculty of Pharmacy (FFUC), evaluated the presence of viruses and bacteria in macroalgae (seaweeds) and halophytes from the Portuguese mainland coast, given the growing association between these products and new, growing trends in healthy food choices.

Given the interest in including them in recipes as unprocessed foods, and in order to assess the possible adverse effects of their consumption in Portugal, a study published in the journal Food Control evaluated the presence of norovirus and Salmonella—pathogens responsible for serious infections that can be transmitted upon ingestion of contaminated food—in approximately 50 samples collected from Vila do Conde to Cascais.

This study showed the high quality of Portuguese coastal waters in terms of norovirus and Salmonella in macroalgae. However, Salmonella was detected in a halophyte collected from one of the sampled beaches. This highlights the importance of preventing the local population from collecting wild species for culinary use," says Elsa Teresa Rodrigues, a researcher at the Department of Life Sciences (DCV) and the Centre for Functional Ecology (CFE), who coordinated the study.

According to the research, information on the potential microbiological hazards of edible macroalgae and halophytes is scarce, and standard methods for detecting norovirus in vegetables have not yet been validated for this type of food.

The researcher explains that "the internationally standardised method NF EN ISO 15216-2 was applied to 57 samples and validated for 72% of the samples. The results show that the method is suitable for green and red macroalgae and halophytes, but needs to be optimised for brown macroalgae. The presence of Salmonella was also tested in 46 samples to confirm potential hazards using the international method ISO/FDIS 6579 and was detected in one halophyte," she concludes.

In 2020, the European Food Safety Authority (EFSA) recognised the possible negative impact of climate change on the quality of products used for human consumption, namely on the level of some food-borne diseases, including those caused by Norovirus and Salmonella.

The scientific article Portuguese macroalgae and halophytes for human consumption: minimal risk of Norovirus and Salmonella infection is available here.