Oysters, not just luxury. Sea delicacies can become a useful tool in addressing malnutrition and pollution. Sources of protein, minerals and B vitamins, oysters indeed deploy social and environmental benefits. A study published in Frontiers in Nutrition shows their ambition to become functional foods with a remarkably mild ecological footprint.
Oysters, valuable nutrition without feed or drugs
Like mussels and clams, oysters are bivalve mollusks, that is, kept in a two-valved, hinged shell. 100g of oysters naturally contain about 10.2g of protein, high levels of Omega 3 essential fatty acids and various micronutrients such as zinc, iron, vitamin A and vitamin B12.
Bivalve farming differs from others, as well as from agricultural farming, in that it does not require feed, fertilizers, or antibiotics. Mollusks actually feed only on the microorganisms in the waters. Thus performing, among other things, a valuable filtering action for the environmental recovery of polluted waters at risk of eutrophication (abnormal growth of algae that prevent the passage of light, which is essential to aquatic fauna).
A natural filter
However, it is precisely the assimilation of dissolved substances in the waters that expose oysters and other shellfish to risks of chemical and microbiological contamination with potential impact on human health. In fact, the consumption of the whole shellfish, as is customary, involves the ingestion of what fed it. Including any harmful microorganisms (from polluted water), viruses (e.g., hepatitis A, norovirus), toxins, and chemicals (such as those used in agriculture and dragged into waterways).
An additional risk factor is related to the mode of consumption, which prefers raw or freshly seared shellfish. In this regard, reg. EC 853/2004 (c.d. Hygiene 2) establishes the obligation to sell or serve raw shellfish only after heat blasting (-20 °C for at least 24 hours). (3) In domestic settings, the same result is achieved by freezing for at least 96 hours at -18°C. (1)
Fortified oysters against malnutrition
The assimilation capacity of oysters has been the subject of a special experimental study, with a view to making functional shellfish. In fact, a group of researchers from the University of Cambridge (UK) has shown how the supply of vitamins A and D in microcapsules results in their high absorption in oyster tissues after only 8 hours.
‘A serving of just two of these bivalves provides enough vitamin A and D to meet human dietary RDAs. Expanding this technology and applying it to other bivalve species, including clams and mussels, could provide a low-cost and highly sustainable mechanism to help address nutrient deficiencies globally.’ explain the researchers. (2)
Ultra sustainable protein
The same British researchers, in another study, examined the environmental impact of bivalve mollusks. Concluding that it is the most sustainable source of animal protein on the planet. (3) A production so virtuous that it is the subject of guidance by FAO(Food and Agriculture Organization) and WHO(World Health Organization). (4)
In fact, bivalve farming has a smaller environmental footprint than most other foods. It does not consume soil (for feed production) or fresh water, taking place in seawater. It has lower carbon emissions than many grain crops and helps restore and protect coastal ecosystems. Added to these virtues is an excellent nutritional profile, as the comparison below shows.
Source: Willer David F., Aldridge David C. Vitamin Bullets. Microencapsulated Feeds to Fortify Shellfish and Tackle Human Nutrient Deficiencies. Frontiers in Nutrition, 2020.
Oysters Made in Italy
Italy is the second largest oyster consuming country in Europe, after France. Oysters are also Made in Italy, but production–concentrated in Sardinia and Liguria (La Spezia province), as well as in the Adriatic, starting with Goro in Ferrara–is just over 200 tons a year. Incomparable to the grandeur of the other side of the Alps, which, despite severe damage caused by viruses and pests, reaches 120,000 tons.
The Italian oyster industry is very promising and deserves to be fostered, precisely because of the nutritional and environmental benefits outlined above. However, producers are plagued by a disproportionate tax regime, as in Italy the oyster is still taxed as a luxury product, with VAT at 22 percent. More than twice as much as almost all aquaculture products, which are subject to 10 percent VAT in Italy. (5) Even three times as much as in neighboring France, which does not even distinguish between huîtres and baguettes, TVA at 6 percent for all.
Marta Strinati
Notes
1) EC Regulation 853/2004, on the‘Sale and serving of gastronomic preparations containing fishery products intended to be consumed raw or practically raw’
2) Willer David F., Aldridge David C. Vitamin Bullets. Microencapsulated Feeds to Fortify Shellfish and Tackle Human Nutrient Deficiencies. Frontiers in Nutrition, 2020. DOI=10.3389/fnut.2020.00102. https://www.frontiersin.org/article/10.3389/fnut.2020.00102
3) Willer, D.F., Aldridge, D.C. Sustainable bivalve farming can deliver food security in the tropics . Nat Food 1, 384-388 (2020). https://doi.org/10.1038/s43016-020-0116-8
4) Technical Guidance for the Development of the Growing Area Aspects of Bivalve Mollusc Sanitation Programmes. Joint FAO/WHO Food Safety and Quality Series https://www.who.int/foodsafety/publications/Bivalve/en/
5) Redemption of Italian oysters: in one month requests +20%. The Messenger, January 2020 https://www.ilmessaggero.it/alimentazione/ostriche_gastroenterite_molluschi-4978705.html
Professional journalist since January 1995, he has worked for newspapers (Il Messaggero, Paese Sera, La Stampa) and periodicals (NumeroUno, Il Salvagente). She is the author of journalistic surveys on food, she has published the book "Reading labels to know what we eat".
