To determine risk, more information is needed on concentrations of nano-Ag in the product, size and form in which it is present and probability of release of silver nanoparticles.
The European Commission and its non-food Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR) published findings after being asked for the opinion in 2012.
Examples of products that contain nanosilver include food packaging materials and food supplements (not allowed in the EU unless specifically authorized).
The migration limit for silver from packaging products into food is 0.05 mg/kg.
Data is limited for the moment: reported levels of silver released from consumer products in different studies are inconsistent, probably due to differences in methodology.
The ‘Nanosilver: safety, health and environmental effects and role in antimicrobial resistance’ opinion concerns risk assessment but not risk management.
A public consultation on the preliminary opinion was open until February 2014.
Aim to assess risk
The aim was to assess whether the use of nanosilver could result in additional risks compared to traditional uses of silver and whether nanosilver to control bacterial growth may lead to in resistance of micro-organisms.
AgNPs can penetrate cells and possibly cause damage but it is premature to say they make you sick, according to a study by Danish researchers .
Products that contain forms of (nano)silver are difficult to track as they are marketed under numerous brand names, and, with a few exceptions, labelling regulations do not specifically require listing nanomaterials as a constituent.
For food supplements with nanosized silver, product labels contain statements about the function like “Purifying and conservation of unknown targets”, “Supporting the immune system” and “Helpful against severe illness”.
Since statements have not been evaluated by the European Food Safety Authority (EFSA) and/or the
European Medicines Agency (EMA), the claim of certain activities cannot be substantiated and may be illegal, especially for health-promoting claims.
Examples of applications of nanosilver in the food chain can be categorised in different stages of food production.
In the processing of food stage, applications include food preparation equipment with incorporated nanosized silver particles as an anti-bacterial coating of food handling devices.
For conservation, food products and packaging materials are mentioned with nanosized silver sprays for antibacterial acton and incorporation of active nanosilver particles for oxygen scavenging and prevention of bacteria growth.
In food consumption, supplements using colloidal metal nanoparticles claimed to enhance desirable uptake.
Quantitative data for the end-of-life phase of products containing Ag-NP is very limited and needs further research. It is assumed that existing waste handling infrastructures would be used for nanomaterial products in a similar way as conventional products.
BfR nanomaterial project
Meanwhile, the Federal Institute for Risk Assessment (BfR) is looking at nanomaterials ingested via food and the affect in the liver and intestine.
BfR will work with its French sister organisation ANSES for a three and a half year project called “SolNanoTox“.
A risk assessment of nanomaterials is hardly possible and involves uncertainty, as toxicological data on their behaviour in tissue and cells are still missing, said the BfR.
The project will examine the role solubility of nanomaterials plays in accumulation and potential toxic properties.
Titanium dioxide will represent water insoluble nanoparticles and aluminium as an nanomaterial which shows a certain degree of water solubility after oxidation.