In the past year there has been an increased incidence in Belgium of cases of positive semicarbazide (SEM) tests in imported freshwater Macrobrachium rosenbergii prawns, seemingly indicating the possible abuse of nitrofurazone, a banned antimicrobial agent. This was in contrast to all other European countries where no significant increase in SEM-positive samples was detected. A possible explanation for this discrepancy between Belgium and the other European Union member states could be the fact that only in Belgium were whole prawns (meat + shell) analyzed for the presence of tissue-bound metabolites of nitrofurans, whereas in the other countries only the edible part (meat) of these prawns was analyzed. To investigate the possible natural occurrence of SEM in freshwater prawns, an animal trial was set up. In this experiment two groups of 10 juvenile M. rosenbergii, previously raised under standardized laboratory conditions, were stocked into two separate aquaria, a control group under reference conditions (no addition of nitrofurazone) and a group exposed to a daily dose of 50 mg of nitrofurazone L(-1) of culture water. Results of this animal trial proved that SEM naturally occurs in M. rosenbergii prawns but that at the current minimum required performance limit (MRPL) no tissue-bound SEM can be found in the meat of nontreated animals. In addition to this animal trial, commercial samples of other crustacean species, the shell and meat of which were analyzed separately, were also analyzed for the presence of SEM.

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In this contribution we will show that research in the field of toxicology, pharmacology and physiology is by and large characterised by a pendulum swing of which the amplitudes represent risks and benefits of exposure. As toxicology usually tests at higher levels than the populace routinely is exposed to, it reverts to mostly linear extrapolative models that express the risks of exposure, irrespective of dosages, only. However, as we will explicate in two examples, depending on dosages, it is less easy to separate risks and benefits than current toxicological research and regulatory efforts suggest. The same chemical compound, in the final analysis, is represented within the boundaries of both amplitudes, that is, show a biphasic, hormetic, dose-response. This is notable, as low-level exposures from the food-matrix are progressively more under scrutiny as a result of increasing analytical capabilities. Presence of low-level concentrations of a chemical in food is a regulatory proxy for human health, but in light of this hormetic dose-response objectionable. Moreover, given that an ecological threshold probably holds for most, if not all, man-made (bio)organic chemicals, these will be found to be naturally present in the food matrix. Both aspects require toxicology to close the gap between reductionist models and its extrapolative deficiencies and real-life scenarios.

Responding to public fears and the loss of confidence in the aftermath of several food safety crises in the 1990s and 2000s, more and more regulatory laws have increasingly been affected by the precautionary principle. To clarify how those developments can have adverse consequences, we discuss two very different cases. First, at the molecular level we discuss the problems the system encounters by strictly applying the linear no-threshold (LNT) at low doses model, which was adopted in response to fears about the effects of ionizing radiations. Second, at a global scale, we discuss the problems associated with the precautionary regulation on Illegal, Unreported and Unregistered Fisheries that came into effect January 1, 2010. The technical aspects of food safety testing and their impacts are perhaps unknown to policy makers but they do dominate safety decisions. Both examples show that strict application of the precautionary principle produce deleterious side effects, which go against the very policy values that the precautionary regulation should protect. We show, in particular, that overly precautionary food safety regulation may harm food security. We conclude in the EU and other Western nations, problems of food security are much more relevant to human health and life expectancy than food safety. We recommend that current food safety regulation based on the precautionary risk-regulation reflex should normatively be re-evaluated with a complete regard for the values of food security – both within and outside the EU.

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