Reading food-risk claims: hazard, risk and why experts disagree

Food-risk claims can describe different questions even when they concern the same substance. A hazard assessment examines a potential source of harm. A risk assessment also examines exposure and the likelihood of an outcome under the conditions being considered. Wikipedia's risk-assessment article describes a process that identifies hazards, their likelihood and consequences, with assumptions and uncertainty made explicit. Reading the question and the conditions alongside a conclusion helps distinguish a scientific assessment from the policy decision made with it.

Hazard identifies a possibility; risk examines conditions

The risk-assessment reference describes hazard identification as identifying potential adverse consequences. It describes exposure assessment as examining the amount of a contaminant that a person or population receives. Dose-response analysis examines how an amount relates to a measured effect, while risk characterization combines the preceding information. In this account of risk assessment, uncertainty analysis is ordinarily part of the assessment. These are connected stages, but their findings are not interchangeable: the presence of a possible hazard does not specify an exposure level or a probability.

Exposure has a route and a duration as well as an amount. Wikipedia's dose-response article explains that changing the exposure time or route can change the relationship being measured and the conclusions drawn from it. A food assessment consequently needs a defined dietary exposure question. A study conducted under another route or set of conditions may still be relevant evidence, but translating it to the question at hand requires an explanation of the assumptions. The pesticide-residue page places these distinctions beside food-residue standards.

Glyphosate illustrates different assessment questions

The International Agency for Research on Cancer states on its glyphosate monograph page that in March 2015 it classified glyphosate as probably carcinogenic to humans, based on limited evidence in humans and sufficient evidence in experimental animals. The agency describes its evaluation as a hazard classification. It says that the classification indicates the strength of evidence and that the probability of an outcome depends on the type and extent of exposure and the strength of the effect. This paragraph reports IARC's assessment, rather than translating the classification into a personal dietary conclusion.

The EPA glyphosate page reports that its 2017 assessment concluded glyphosate was not likely to be carcinogenic to humans and identified no dietary risks of concern. EPA explains the difference in scope: IARC considers whether a chemical can cause cancer under any conditions, while EPA assesses expected real-world exposures. The agency also describes different bodies of evidence used in evaluation. These are the agencies' reported conclusions and explanations; this reference does not select one classification as the verdict that readers must adopt.

There can also be differences in which studies are available for examination. IARC explains that its monograph relies on information available publicly for independent review, including industry studies meeting that criterion. EPA describes considering studies submitted through registration as well as other available research. Reporting this distinction does not establish that one body has answered every question considered by the other. The methods, the exposure conditions and the stated limitations belong beside each agency's conclusion.

Substantial equivalence organizes a comparison

For engineered foods, substantial equivalence is a comparative framework. Wikipedia's substantial-equivalence article describes comparing a new food with a conventional counterpart, then examining differences that may require further testing. The comparison can concern the harvested crop, a processed fraction or the final food, depending on the product and its use. The article emphasizes that substantial equivalence is a starting point for assessment, rather than a substitute for risk analysis. The engineered-food overview places this comparison within the agencies' review responsibilities.

That approach is also part of debate about testing. Wikipedia's engineered-food controversies article describes plaintiffs who argued that engineered foods should receive the same testing requirements as food additives because they may contain material changes and unidentified health issues. It records that the court rejected those arguments. The testing concern is presented here as an argument made in that dispute, not as an established finding about engineered food. It differs from describing what a comparative assessment actually examines.

Precaution concerns decisions under uncertainty

Wikipedia's precautionary-principle article describes an approach to decisions where a plausible possibility of harm exists and extensive scientific knowledge is lacking. Its formulations differ in how they handle the burden of proof, the costs of action and the seriousness or reversibility of a possible outcome. The article also summarizes criticism concerning the principle's vagueness and possible effects on technological progress. Those arguments concern how to decide under uncertainty, rather than simply whether a laboratory result has been measured correctly.

The same article explains that the precautionary principle has legal standing in parts of EU law and that the United States has opposed the term principle in international negotiations because of its legal implications. It distinguishes stronger and weaker formulations, including differences in whether costs can be weighed. The precautionary-principle reference therefore does not support treating every precautionary policy as identical, or assuming that every difference between jurisdictions is a disagreement about the same exposure estimate.

Scientific advice and regulatory decisions

Wikipedia's European Food Safety Authority article describes EFSA as providing scientific advice to support decisions by European institutions and member states. That distinction between assessment and management is useful when comparing a scientific report with a legal restriction. The U.S. agency map and the rulemaking explainer describe the corresponding institutional and procedural questions. A source's conclusion is clearest when its subject, evidence, exposure assumptions and decision-making role are all visible.