XIWhat is XI?

The tool

The XI tool is another application that was developed on request of different users of this portal. For assessing health risks of chemical substances in food or feed it is common practice to calculate intake of the chemical using conservative conditions, such as the highest concentration reported in combination with a high percentile (e.g. 95%) for consumption. Although this is describing a real situation, one should be aware of the fact that such scenario has a very low probability, and might therefore not be representative for the situation to be evaluated. Besides one should be aware that many foods are consumed on a certain day by only a small percentage of the population, thus making the situation of exposure more unlikely for the general public.

Calculate variation

A better way to estimate "real" exposure to chemicals from food or feed is to calculate intake of the chemical for each consumer separately. The result is a list of numbers, with zero values for non-consumers, and different values for the various consumers. The individual intake per kg bodyweight can then be established using the actual body weight of that consumer in stead of using an average weight. Then the results express the variation of the intakes, making it possible to find values for the median exposure and its percentiles (and to find outliers!). And, to find the factual percentage of the population that exceeds a Health Based Guidance Value.

Monte Carlo

Another speciality of XI is the possibility to use a series of concentrations of the chemical substance for the calculations, in stead of a single number. In this way one can evaluate the full report of a laboratory rather than select one value from all findings. In this case the tool will select the numbers from the list in a random manner. So, here the variation of the consumption from different consumers is combined with the variation of the concentration of the chemical substance in different samples, leading to a better picture of the variation of the intake.

Cumulative exposure

XI (as most comparable tools) can only evaluate one chemical substance in one food commodity. For some contaminants however, increased levels will be found in different commodities, e.g. dioxins in milk, and meats, and oils, and fish. In these cases the risk assessor is interested in the total exposure from all food items, rather than exposure from one commodity. Some experts refer to this as cumulative exposure assessment. XI can not directly handle such a case, but it can help you to calculate the total exposure thanks to its output, as its output is a (csv) file with an unique id for each consumer. Multiple .csv files can be imported in computer applications such as Microsoft Excel or Open Office Calc, or be read by statistical software such as R and SAS. The different files for various commodities can then be combined using that the consumer-id. The intake levels can now be combined, e.g. to calculate total intake from all relevant foods.


XI uses a Dutch food consumption database of the period of 2012 to 2016, and as such it will calculate intake of chemicals from food as will occur in the Netherlands. How about your country? If your organization is in the possession of a (national) dataset with consumption patterns of food commodities that you would like to use for intake calculations similar to those of XI, then you are advised to contact the author of this website to discuss the possibility to add your data into the XI tool for similar type of calculations.

To demonstrate how your own XI-like tool would look like, go to the XI tool that is using the ImproRisk database from Cyprus.

How to use

In an additional page more information can be found on how to use XI..