EFSA gives go-ahead for threshold of toxicological concern (TTC) chemical screening

EFSA’s Scientific Committee was tasked with evaluating the TTC approach as a tool for providing scientific advice about possible human health risks from low level chemical exposure in food and feed.

The approach, which EFSA has previously only used  to evaluate flavouring substances and relevant pesticides in groundwater, involves the risk assessment of a substance on the basis of generic human thresholds of exposure for chemicals, which are called TTC values

These values are categorised as either of low, moderate or high toxicity. If human exposure to a substance is below the TTC value, the likelihood of adverse effects is considered to be very low.

The Committee, which provides scientific and strategic advice to EFSA on new risk assessment approaches, concluded that TCC could be recommended at a “useful screening tool.”​

Useful screening tool​

According to EFSA’s evaluation, Scientific Opinion on Exploring options for providing advice about possible human health risks based on the concept of Threshold of Toxicological Concern (TTC),​ the approach will aid policy-makers where there is insufficient data to carry out a risk assessment.

“Synthetic and naturally occurring substances present in food and feed, together with their possible breakdown or reaction products, represent a large number of substances. Many of which require risk assessment,”​ said the EFSA scientific opinion.

“The Scientific Committee concluded that the TTC approach can be recommended as a useful screening tool either for priority setting or for deciding whether exposure to a substance is so low that the probability of adverse health effects is low and that no further data are necessary.”​

“The continuing improvements in analytical sensitivity are also resulting in the detection of a growing number of chemical contaminants in food and feed at low concentrations, as well as in the identification of substances on which there are few toxicological data.”​

TTC criticised​

Its consideration of the approach has previously received criticism, with many arguing that any chemical found to be present in food or feed should be subjected to toxicity testing followed by risk assessment.

“Specifically, this knowledge can allow scientists to give guidance to risk managers even when there are few toxicity data available, particularly for chemicals which cannot necessarily be removed from the diet,”​ said EFSA previously.

According to EFSA, the TTC approach has been used by the US Food and Drug Administration (FDA) and the Joint Expert Committee on Food Additives of the U.N.’s Food and Agriculture Organisations and the World Health Organisation (JECFA).