Left-censored data and where to find them: Current implications in mycotoxin-related risk assessment, legislative and economic impacts

Background: One of the most challenging steps in chemical risk assessment is the dietary exposure due to the high percentage of left-censored data (LCD). Mycotoxins are the group of chemical contaminants known to show the highest percentage of LCD among chemical contaminants. These data are extremely important especially if they are used for the development of new legislations with permitted maximum limits. Scope and approach: In this study, we address the importance of analytical techniques and current methods of dealing with LCD, with the goal of highlighting the effect of LCD on risk assessment, which could have a potential impact on future regulations of mycotoxins in foods and the economic implications of such regulations. Key findings and conclusions: Thirteen European Food Safety Authority (EFSA) Scientific Opinions and Reports on the risk of mycotoxins to humans were evaluated. The most used analytical method was based on Liquid Chromatography-Mass Spectrometry (LC-MS). Most of the occurrence data for mycotoxins in EFSA risk assessments over the last decade were condensed between 80 and 100% LCD. The typical statistical methods to handle LCD, the substitution method and cut-off values approach, frequently lead to the overestimation of the human risk which can ultimately lead to stricter law regulations with economic implication on the agricultural trades. Understanding the obstacles that analysts face and the type of data that risk assessors require will help to close the uncertainties and gaps that currently exist in exposure and risk assessment. Establishing limits of detections (LODs) and limits of quantification (LOQs) while having a clear data purpose can help reduce uncertainties in risk assessment and provide more meaningful exposure evaluations.