Some Highlights by GreenFacts of the draft report : State of the art on the initiatives and activities relevant to risk assessment and risk management of nanotechnologies in the food and agriculture sectors, FAO-WHO, 2012
This draft report was submitted to public review which ended in November 2012. These Highlights will be adapted when the final report will be issued.
Food can be cultivated, produced, processed or packaged with nano-technology, or engineered nanomaterials can be added to food. Recent scientific reviews on risk assessment of nanotechnologies in the food and agriculture sectors, says the draft report, confirm that information on this topic is limited .
A section of this draft FAO/WHO report briefly summarizes national and regional initiatives and activities related to the risk assessment and risk management of nanomaterials, such as research projects, development of guidance documents and drafting of regulations, that have been carried out. Emphasis is placed on issues that contribute to the definition of the term “nanomaterials” (to be subjected to specific risk assessments) and case-studies where a riskassessment has been undertaken for a defined material.
The Highlights of the report in nine Questions and Answers
1. What do we know on the impact of nanomaterials found in plants?
A review on the interaction of nanoparticles with edible plants found that understanding of plant toxicity is at the early stages. Few studies have been performed on the accumulation of engineered nanomaterials in crop plants such as rape, radish, lettuce, corn and cucumber noted that among the studied nanomaterials, the carbon-based nanomaterials fullerenes C70 and fullerols C60(OH)20 and most of the metal-based nanomaterials (titanium dioxide, cerium oxide, magnetite, zinc oxide, gold, silver, copper and iron) accumulated in the plants. These compounds stored in the plants can be transferred to consumers. Depending on the studied reference nanomaterial and plant, negative effects of the nanoparticles on the food crops were observed, such as reduced germination, reduced root growth and delayed flowering.
2. What do we know of the impact on human health of nanomaterials present in food?
An evaluation of the published literature on the safety of oral exposure to food-related nanomaterials found that there are currently insufficient reliable data to allow a clear safety assessment. A study reported in the draft FAO/WHO document also considered that non-food-related engineered nanomaterials require evaluation of oral toxicity in light of possible contamination of the food supply and one concluded that the lack of information on the possible toxicity of nanomaterials makes it difficult to assess the safe or acceptable daily intake.
3. Is the potential impact of nanomaterials in food adequately evaluated at present stage ?
A study cited in the draft FAO/WHO report considers that literature on the safety of oral exposure to nanomaterials inadequately characterizes nanomaterials with insufficient physicochemical parameters, concluding that “Unless nanomaterials are adequately characterized, the results of the toxicology studies cannot be utilized to predict toxicity of other nanomaterials as changes in any of the characteristics may result in changes in biological activity”.
Some authors, also cited in the draft report, reasoned in particular that in vitro and in vivo tests with no characterization of the nanomaterial are meaningless and that at the present time, risk evaluation requires characterization of each substance and each product.
4. What about the risk for occupational exposure to these nanomaterials?
According to one of the review cited, there is at present little information on the effect of antimicrobial nanomaterials such as nanosilver on normal microbial populations in the mouth and gut. There has been more interest in occupational health, such as nanoparticle toxicology in the lung, and less research has been published on nanomaterial toxicity in the gut.Few studies cited in the draft report have attempted to find a relationship between the presence of nano-sized particulate materials in food and the initiation and/or worsening of certain gut diseases, such as Crohn disease and irritable bowel syndrome and produced contradicting results; therefore, there is a requirement for considerable further research.
5 . How perform a reliable safety assessment of these chemicals used in food and agriculture?
The safety assessment of nanomaterials will depend on their adequately characterized chemical properties underlines the report; critical parameters include biopersistence and digestibility, says the drat report. Based on the development of nano forms of trace minerals, a group identified three different scenarios :
- - Digestible, non-biopersistent nanomaterials such as nano forms of a salt will be digested (dissolve) prior to any cellular exposure; for cells and tissues, there will be no difference if compared with conventional forms.
- - A second type of digestible, non-biopersistent nanomaterial, such as micellar nano formulations or ferritin, will only partially degrade in the gut; and may therefore be absorbed as nano structures but will be rapidly broken down in cells.
- - A third type, non-digestible, biopersistent nanomaterials, may remain intact and will raise different issues, an important one being their adsorbed surface materials, which may be removed in the stomach and replaced in the gut by luminal molecules before cellular uptake.
Some authors identified three principles that in their view describe specific aspects of the separate discipline of “nanotoxicology” :
- The principle of transport requires an understanding of whether and in what form nanomaterials will enter into cells where they may elicit a toxic response ;
- The principle of the surface which reflects the fact that for smaller particles with active molecules on their surface, the proportion of atoms or molecules that are exposed and may therefore react with biological structures increases exponentially with decreased diameter if the same amount is administered.
- The principle of material which states that changes in dimensions (i.e. going towards nano) will not have the same effects but will depend on the properties of the material and its composition, including impurities.
6. How nanomaterials used in food and agriculture should be evaluated?
Risk assessment has always been done with defined chemicals, with no attention paid to particle size and there is not enough known about nanomaterial toxicity to be able to group the particles into low-toxicity or high-toxicity groups, says the draft report. Therefore, nanomaterial risk assessment currently needs to be done on a case-by-case basis including more attention given to ingestion exposure. Nanomaterials would be within the scope of the main areas of classical chemical risk assessment at the international level address food additives, pesticide residues, veterinary drug residues, some processing aids, such as enzymes, and occasionally micro-nutrients. For a “nano-plastic material” to be used in food packaging, however, there is no risk analysis framework at the international level currently in place. Furthermore, says the draft report, as agencies apply different strategies with respect to communication, it is difficult to develop a clear picture of the true number of substances assessed and the issues discussed that are specific for nanomaterials.
7. What are the main conclusions of the draft FAO/WHO report regarding the use of nanotechnology?
The conclusions underline that new products are being developed and probably enter the market, but the available data from published sources do not allow an assessment of whether product ideas are just concepts or are already resulting in exposure of consumers to food being produced with nanotechnology/nanomaterials at any significant rate.
Whether a product would be considered to be a nanomaterial or representing an application of nanotechnology also depends on available definitions applied by regulators. There is a trend to apply in the definitions two criteria, an altered or new dimension at nanoscale and a concurrent change of properties due to the change of dimension. A true nanomaterial that requires the attention of regulators and a specific risk assessment would need to meet both criteria, says the draft report. The proposal of a tiered approach for classifying 766 nanomaterials for risk analysis purposes would apply several criteria, of which dimension and change of properties expected to result in a modified hazard identification and characterization would be two important ones.
8. What are the main conclusions of the draft FAO/WHO report regarding the assessment of human health risks?
The conclusions recognises that national and 21 regional food safety agencies increased their focus during the past few years on investigating the implications of nanomaterials added to or used with food. Policies and guidance documents have been published that allow a better understanding of how risk assessment of nanomaterials will be performed in the future.
OECD reviewed its globally accepted testing guidelines for hazard identification and characterization of food chemicals, such as additives, pesticides and veterinary drugs, and other substances resulting in human exposure, such as cosmetic ingredients and found them to be generally applicable for the testing of nanomaterials.
The approach to be published by ILSI for nanomaterials to be used in food is interesting, underlines the draft FAO/WHO report, as it tries to systematically review the information already available for conventional material and discusses what properties would allow extrapolation from conventional to novel nanomaterials. Further development and implementation of this concept may lead to reduced animal testing. The tiered approaches that are discussed may allow in vivo testing for specific groups such as nano-salts of micronutrients to be waived.
Therefore, concludes the draft report, in accordance with the recommendations of the Science and Technology Committee of the United Kingdom Parliament, it may be valuable to develop a database of information on nanomaterials in development, in collaboration with the food industry, to anticipate future safety assessment needs and to aid in the prioritization of research.
9. What does the draft report say about stakeholder dialogue and confidence in these matters?
For this report, it was difficult to assess the extent to which engineered nanomaterials are already being used in the food and agriculture sectors. Inventories that register nanotechnology in consumer products are scarce; only one database is publicly available.
The draft report notes that in a report on the European Commission’s public online consultation among key stakeholders about nanomaterials, the majority of the 716 respondents regarded applications in agriculture and food with more scepticism than applications in other areas and that the major concern was the possible toxicity of poorly understood nanomaterials. Besides inventories, concludes futher the draft report, while mandatory labelling would lead to greater transparency for the consumer and enable consumer freedom of choice, such mandatory labelling could also lead to the avoidance of the use of nanotechnologies in consumer products, including those that are beneficial.
The original draft of this report was written by Manfred Luetzow, an international consultant for the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO). The development of the report was coordinated by Masami Takeuchi (FAO) and Kazuko Fukushima (WHO).
FAO and WHO acknowledge the responses and comments provided by the following individuals: Junshi Chen, Chinese Center for Disease Control and Prevention; Djien Liem, European Food Safety Authority; Nick Fletcher, Food Standards Australia New Zealand; Alessandro Chiodini and Richard Canady, International Life Sciences Institute; Rosetta Newsome, Institute of Food Technologists; Dora Pereira, MRC Human Nutrition Research; Mar Gonzalez, Organisation for Economic Co-operation and Development; Jed Costanza, United States Environmental Protection Agency; and Annette McCarthy, United States Food and Drug Administration. Technical contributions from several FAO and WHO colleagues are also gratefully appreciated.
Note : the Highlights of recent reports are not reviewed by the Scientific Board of GreenFacts