Nano risk assessment a work in progress

In its opinion issued in Spring last year, the European Food Safety Authority (EFSA) sought to lay down an overarching system to use as a risk assessment framework for nanotechnology – but was clear that much currently remains unknown about nanomaterials and how they behave in food and packaging.

A further guidance document, the first draft of which is due to be published next month, is intended to fill in some of those gaps with practical advice.

But such nano knowledge gaps have led some to call for a ban on the use of nanomaterials in food products until their safety has been fully established. One area of concern is whether nanoparticles can migrate from packaging materials into foods.

EFSA position​

EFSA’s opinion, published in March 2009, was candid in stating that current uncertainties of risk assessment of engineered nanomaterials (ENM) and their applications in food and packaging arose because of the current “limited information on several aspects” of the technology

In seeking to assess nanomaterials, the food safety body repeatedly used phrases such as “specific uncertainties”, “limited knowledge” and described ENMs as “difficult to characterise, detect and measure” in relation to toxicokinetics and toxicology in food. Likely usage and exposure levels are also largely a mystery, said the Parma-based experts.

But despite such a patchy picture, EFSA’s Scientific Committee declared it was possible to apply internationally established risk assessment criteria to ENMs – namely those of hazard identification, hazard characterisation, exposure and risk characterisation.

The body added that significant knowledge gaps meant assessment of risk must be carried out on a “cautious case-by-case approach” as it included some significant caveats into this overall risk assessment conclusion.

Firstly, it said that risk assessment must take into account the specific properties of ENMs in addition to those of equivalent non-nanoforms. It is likely that toxicological properties may vary between ENMs and information on oral exposure to the materials is also “extremely limited”, added the EFSA scientists.

The body highlighted the need to build up risk assessment profiles for ENMs – including identification and characterisation, and whether they will be ingested in nanoform.

The committee said that while a case by case analysis “may currently be possible”, it stressed “risk assessment processes are still under development”. It recommended that methods to detect and measure ENMs in food should be developed and that a map detailing the extent of their use in foods be drawn up. More information was also needed on human exposure and ENM toxicity data.

Referring to the risk assessments, Prof Vittorio Silano, EFSA Scientific Committee chair, said: “Given current data gaps and limitations in a number of cases, it may be very difficult to provide fully satisfactory conclusions.”​

The agency has formed an expert working group and is currently preparing further risk assessment guidance. This will provide practical recommendations on how to assess industry applications on ENM use in everything from food contact materials, novel foods, enzymes and food supplements. A first draft is scheduled to appear in July.

Nano concerns​

The lack of certainty over ENMs has led some to push for a more cautious approach to their permitted use. The Swiss Centre for Technology Assessment (TA-Swiss) last year called for existing legislation to be adapted to meet the challenges posed by nanomaterials. It said Europe-wide regulation was needed in relation to ENMs in packaging and food.

The researchers examined the issue of migration from nano-packaging into food and concluded that this was primarily dependent on how the nanolayer was applied.

“In general terms, it must be said that in the case of laminated films with a nanolayer silicate plastic grid, it is least likely that nanoparticles will be leached out of the packaging,”​ said the body. “But where the food is in direct contact with the nanolayer, there is a greater risk that it will pick up nanoparticles from it.” ​

EU politicians have also expressed fears over the availability of products using nanotechnology prior to the completion of proper risk assessment.

Last April, the European Parliament’s environment committee called for the withdrawal of products containing nanotechnology which are already on the market until safety assessments can be made. Earlier this month, the committee also said that foods produced by nanotechnology processes must undergo a specific risk assessment before they can be approved for use and labelled.