Emerging Contaminants
A toxicological point of view can help close off concerns about bioaccumulating compounds, and other natural and man-made contaminants.
An emerging contaminant can be a newly recognized entity or a known compound that presents new characteristics or risks. In either case, new analytical approaches may be required to guarantee consumer safety. For example, arsenic speciation is now necessary to discriminate between organic compounds, for example, arsenobetaine in fish, and inorganic arsenic, which is of far greater concern. And organotins, which show significant immune and endocrine toxicity, need to be differentiated from the background tin in foods.
From a food analysis standpoint, emerging contaminants include compounds that are not yet fully integrated into routine monitoring, yet are able to bioaccumulate. Brominated flame retardants and perfluorinated compounds are two such examples.
Bioaccumulating compounds mainly enter the food chain in commodities of animal origin: they are deposited and metabolized in different tissues and in different animal species. Such information informs detection strategies, but bioaccumulation is not always straightforward; for example, perfluorinated compounds are unusual in that their accumulation is unrelated to lipophylicity.
An emerging contaminant can be a newly recognized entity or a known compound that presents new characteristics or risks. In either case, new analytical approaches may be required to guarantee consumer safety. For example, arsenic speciation is now necessary to discriminate between organic compounds, for example, arsenobetaine in fish, and inorganic arsenic, which is of far greater concern. And organotins, which show significant immune and endocrine toxicity, need to be differentiated from the background tin in foods.
From a food analysis standpoint, emerging contaminants include compounds that are not yet fully integrated into routine monitoring, yet are able to bioaccumulate. Brominated flame retardants and perfluorinated compounds are two such examples.
Bioaccumulating compounds mainly enter the food chain in commodities of animal origin: they are deposited and metabolized in different tissues and in different animal species. Such information informs detection strategies, but bioaccumulation is not always straightforward; for example, perfluorinated compounds are unusual in that their accumulation is unrelated to lipophylicity.
A further complication is that multiple related contaminating compounds can be present in the same food commodity. Take the endocrine-active polybrominate diphenyl ethers (PBDEs) as an example. These comprise over 200 congeners that might be present in fatty foods. As with PCBs, only the most representative ‘marker’ PBDE congeners are monitored in food and animal feeds. It is equally important to identify compounds or congeners that may be grouped together because of a common mode of action as is the case for dioxin-like compounds, which can be monitored as a group according to their additive mechanism of toxicity, which is interaction with aryl-hydrocarbon receptors. A mechanism-based grouping could also be applied to clusters of the main non-dioxin-like PCB congeners. The most representative PBDEs seem to have analogous toxicological targets, albeit with different potency, so there is potential for additive toxicity and for a more comprehensive test.
On a positive note, I believe that there is great scope for the development of in vitro methods, such as the use of cell lines and biosensors, that target relevant biological activities in foods. Examples include antioxidant potential and steroid receptor transactivation. These tools could contribute to a ‘whole food’ assessment, incorporating the effects of foreign and natural substances present in the food. From a practical point of view, in vitro methods would aid efficient risk management along food chains, acting as a first-tier screen ahead of targeted chemical analyses. Multi-parameter platforms that provide time-effective responses would be of great value. One can imagine batteries of multiple biosensors targeting different parameters and placed at critical points of the production chain. I envisage that studies on the predictive value, robustness and cost-benefits of in vitro methods for food chain analysis will take off.
In conclusion, we are witnessing the development of food analysis integrated with toxicological input. Monitoring emerging contaminants, exposure assessment and trend monitoring is of paramount importance.
Please read the other articles in this series:
Non-Targeted Analysis
Foodomics
Regulating Food Allergens
Electronic Senses
Alberto Mantovani is proud of his background in veterinary medicine, because he deems that it can provide a horizontal, cross-cutting approach to problems. As a young graduate, however, he became fascinated with research, and in particular with experimental toxicology as an emerging field. That field constituted his role from 1985 at the Italian National Health Institute (Istituto Superiore di Sanità). “Toxicology led me to be acquainted and interact with peculiar people like analytical chemists, molecular biologists and human physicians”. He has also had to deal with emerging (or re-emerging) issues, such as endocrine disrupters and nanomaterials. “I’m becoming more and more fascinated by risk assessment and currently (and rather happily) devote much of my time as an expert for the European Food Safety Authority.”
