Objectives
Through their diet, people are exposed to a wide range of chemicals, many of them at low levels. Some of these chemicals are man-made, and some are naturally occurring or added to food in order to improve its taste, colouring, anti-oxidative and anti-microbial properties. Typically these substances cause no demonstrable health risks to humans. The question now is how to deal with the contradiction that, on the one hand, animal experiments with isolated substances can accurately demonstrate the toxicological potential of chemical substances, whereas, on the other hand, there are no data for humans that indicate a health risk at low intake levels.
The Threshold of Toxicological Concern (TTC) is a principle that assumes the existence of a human exposure threshold for most chemicals below which there is a very low, negligible probability of any risk to human health. The concept that there are levels of exposure below which there are probably no adverse effects is inherent in setting acceptable daily intakes (ADIs) for chemicals with known toxicological profiles. The TTC concept extends this concept by proposing that a threshold can be identified that applies to most chemicals, or to groups of chemicals.
The TTC concept is currently applied to food flavours by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and the European Food Safety Authority (EFSA). EFSA is however considering extending its use to other areas. Additionally, the Committee for Medicinal Products for Human Use (CHMP) based their “Guideline on the limits of genotoxic impurities in pharmaceuticals” on the work of this task force.
Activities
Application of the TTC Concept to Trace Substances in Food
After having developed the science of the TTC Concept, the task force aims at furthering application. As producers of food and food contact materials, enforcement bodies, the European Commission and European Food Safety Authority need to assess the potential risk of trace substances and to set the correct priorities for their risk assessment, a scientifically sound way for the application of the TTC concept shall be developed.
The task force held a brainstorming meeting with experts in spring 2007 in order to discuss the issues related to qualifying and quantifying trace substances and to further define the scope and feasibility of the project.
An Expert Group will be set up by the task force to carry out the project. The results of their work will be published in a peer-reviewed scientific journal.
The task force might envisage to organise a workshop to review the publication prepared by the Expert Group.
Application of the TTC Concept to Chemicals in Non-food Products
Recent publications explore the use of the TTC concept to personal and household care products, cosmetics and food contact materials. However, the task force is currently investigating further research needs in this area and might consider to set up an expert group to address open questions.
Translation
In order to reach a broader audience, the task force will translate the ILSI Europe Concise Monograph on the Threshold of Toxicological Concern (TTC) from English to Japanese, Portuguese, and Spanish.
Task Force Collaborators
The scientists below participate in the task force:
Experts from supporting member companies
Mr. James Edwards, DSM (CH)
Dr. Manuel Dominguez Estevez, Nestlé (CH)
Dr. Heli Hollnagel, Dow Europe (CH)
Dr. Hervé Lafforgue, Groupe Danone (FR)
Dr. Gladys Ouédraogo-Arras, L’Oréal (FR)
Dr. Robert Safford, Unilever (UK)
Dr. Jürgen Schnabel, Givaudan (CH)
Dr. Gunna Würtzen, Coca-Cola European Union Group (DK)
Experts from public institutes
Prof. em Andy Renwick, University Southampton (UK)
Dr. Angelika Tritscher, World Health Organization - WHO (CH) - Observer
Publications:
S. Barlow. Threshold of Toxicological Concern (TTC) –A Tool for Assessing Substances of Unknown Toxicity Present at Low Levels in the Diet. ILSI Europe Concise Monographs Series 2005:1-31.
R. Kroes, A.G. Renwick, M. Cheeseman, J. Kleiner et al. Structure-Based Thresholds of Toxicological Concern (TTC): Guidance for Application to Substances Present at Low Levels in the Diet. Food and Chemical Toxicology 2004;42(1):65-83.
S. Barlow, G. Kozianowsky, G. Würtzen and J. Schlatter. Threshold of Toxicological Concern for Chemical Substances Present in the Diet. Food and Chemical Toxicology 2001;39(9):893-905.
Also published in the ILSI Europe Report Series 2000:1-22.
R. Kroes, C. Galli et al. Threshold of Toxicological Concern for Chemical Substances Present in the Diet - A Practical Tool for Assessing the Need for Toxicity Testing. Food and Chemical Toxicology 2000; 38(2-3):255-312
To download the poster of the Threshold of Toxicological Concern Task Force, click here.
For more information about the task force contact info@ilsieurope.be.