February 20, 2014

expert reaction to food packaging chemicals and health

Environmental scientists commenting in the Journal of Epidemiology and Community Health raised concerns over long term health impacts of chemicals used in the packaging, storage, and processing of foods.

Prof Tony Dayan, Emeritus Professor of Toxicology, University of London, said:

“This commentary mixes some facts about a small proportion of the chemicals it lists with a great deal of speculation about possible effects over long periods of exposure to very low doses and adds in as well a number of extrapolations that lack any reasonable factual basis. It also relies on information about some substances, e.g. organotins, that is incorrect.

“Food packaging materials are already regulated and their properties, functions, composition and migrating substances are regulated to a much greater extent than is suggested in this editorial, as would be apparent if the publicly available records of the relevant European and international agencies [WHO, FAO, JECFA etc] had been more thoroughly explored. The range of experiments and analyses done to explore possible harmful effects is far wider than is suggested here, and conventional toxicity testing does have the potential to reveal any toxic effects if there are any, and the toxicology field has a great deal of experience in making safety predictions for humans. The true place of ‘Endocrine Disrupting Chemicals’ as dangers to humans has yet to be determined as the continuing controversies in the current scientific and medical literature shows.

“The open appeal for considerable, very long-term funding for epidemiological research ignores the problem of how to monitor the exposures of very large numbers of people to many different substances over very many years.

“A very important omission from this plea for a huge amount of support is the complete absence of any consideration of why food packaging is so important in preserving foodstuffs and maintaining perishable items of the diet in a hygienic and acceptable condition.  Without proper packaging our diet would be much poorer in quality and often in quantity owing to the perishable nature of many foods and the well-known dangers of eating contaminated or damaged foods.”

Prof Andy Smith, senior scientist at the MRC Toxicology Unit (in Leicester), said:

“Contamination of food by packaging is not a new issue and is already the subject of European and other studies.  Many of the chemicals detected already are of such low levels that they are likely to pose no significant risk to consumers.  The authors propose widening the net to analyse so many chemicals along the food chain, and in relation to so many different biological processes, that it is unlikely that any significant causal findings would be achieved through epidemiological studies, which would require large scale resources.  The logistical problems would be immense.  In contrast, the health benefits of the packaging and distribution (such as preventing food from spoiling and preventing microbial contamination) are rarely addressed.”

Prof Sir Colin Berry, Emeritus Professor of Pathology, QMUL, said:

“This is part of the continuing problem of Hazard identification rather than Risk Management – to define a risk you must be able to attach a numerical value to an exposure – so much compound produces so much effect. Here we have the assertion that very small exposures to certain compounds may have an effect but none has been demonstrated.  Some of the substances listed by the authors may cause effects at high doses from direct exposures and these have already been banned – the risk has been managed.  It is unlikely that compounds eluted from packaging have significant damaging effects on health because the doses experienced by people are very, very low. 

“No consideration is made in this commentary of likely benefits of the substances used in food packaging; they prevent contamination during handling (bacterial and viral) they prevent deliberate tampering (which has been previously documented with over-the-counter medicines and in deliberate introduction of harmful agents into foods), and there is also the simple point that you have to have something on which to print information about the foodstuff inside.”

Prof David Coggon, Professor of Occupational and Environmental Medicine, MRC Lifecourse Epidemiology Unit, University of Southampton, said:

“It is well recognised that leaching of chemicals from food contact materials may pose risks to health, and the European Food Safety Authority has an expert panel that advises on this problem.  Based on toxicological assessment, maximum levels of contamination from, for example, plastics, are legally prescribed, and testing is carried out to ensure compliance.  Sometimes products have to be withdrawn because they breach the limits.

“That said, several aspects of the article by Muncke and colleagues are misleading.  While formaldehyde has been classified as a human carcinogen, there is strong evidence that any effects on the risk of cancer, even from very prolonged high exposures, are small.  Moreover, formaldehyde is formed naturally in the body, for example from methanol that is present in fruit.  Thus we should only be concerned about relatively high exposures to the compound, and even then, any risks will be extremely small.

“While it is important to consider the potential risks from endocrine disrupting chemicals in the diet, and this is done as part of regulatory risk assessment for chemicals, many of the most potent dietary endocrine disruptors are naturally occurring chemicals such as in soya.

“The article refers to possible toxic effects from combined exposures to multiple contaminants which individually are all at low levels, but understanding of this area of science has advanced a lot in the past 15 years, and there is little to suggest that such combined exposures pose a threat to health other than in a few very specific circumstances.

“As an epidemiologist, I have serious doubts about the contribution that epidemiology can make to this area of science.  Epidemiology thrives on contrast, and small effects on risks in the individual are difficult to discern with confidence, especially when relevant exposures cannot be assessed with accuracy.  Looking for small effects of combinations of dietary contaminants is much more difficult than looking for small effects of air pollution.”

Prof Jon Ayres, Professor of Environmental and Respiratory Medicine, said:

“This opinion piece examines the role of substances used in food packaging and flags up some recognised molecules such as tri-butyl tin causing problems in marine mammals and the ever discussed issue around endocrine disrupting substances.  The issue which the authors raise is that we do not know what the effects are (note “are” not “may be” – we do have ideas about what effects may be but there has been no concrete evidence about what they definitely are) of substances used in food packaging and in so doing they paint a somewhat alarmist picture.  There is no denying that lower doses of some substances ingested over long periods may in principal have a deleterious effect but the issue is how to recognise any such effects and then to quantify these effects.  But can these effects really be anything other than modest at worst when few have been recognised to date?  A call for a different approach to these substances does not really help.  Efforts need to be concentrated on controlling use/emission of those substances already known to effect health, such as lead, which although controlled in the UK is still used in a less regulated way on other countries.  Understanding the cycle of emission, effect and control in these known situations may help shed more light on those molecules which have a smaller effect, but for which convincing evidence is so far lacking.”

‘Food packaging and migration of food contact materials: will epidemiologists rise to the neotoxic challenge?’ by Jane Muncke et al. published in the Journal of Epidemiology and Community Health.