Identifying core foods for total diet studies: a comparison of four different approaches

Reusability of Germany´s total diet study food list upon availability of new food consumption data-comparison of three update strategies

BACKGROUND

The German total diet study (TDS)-BfR MEAL Study-established its food list in 2016 based on food consumption data of children (0.5-<5 years) and adults (14-80 years). The list consists of 356 foods selected for analysis in order to ensure ≥90% coverage of the diet. Recently, new food consumption data for children (0.5-<6 and 6-<12 years) in Germany became available, which raised the opportunity to evaluate the applicability of the MEAL food list 2016 on new data.

OBJECTIVE

We tested the hypotheses that the MEAL food list 2016 also covers ≥90% of the diet of the new collected food consumption data, and that the selection of foods from younger children and adults was sufficient to also cover the middle age group (6-<12 years). Strategies for updating the existing food list were assessed.

METHODS

Three approaches evaluated the reusability and potential adjustment strategies of the existing food list. Approach 1 applied the existing food list to new food consumption data. Approach 2 allowed the extension of the existing food list to improve coverage of food consumption. Approach 3 set up a new food list based on the new data.

RESULTS

The MEAL food list 2016 covered 94% of the overall diet of the new collected food consumption data. The diet of the middle age group was sufficiently covered with 91%. However, coverage on main food group or population subgroup level was <90% in some cases. Approach 3 most accurately identified relevant modifications to the existing food list. 94% of the MEAL food list 2016 could be re-used and 51 new foods were identified as potentially relevant.

SIGNIFICANCE

The results suggest that a high investment in the coverage of a TDS food list will lower the effort and the resources to keep data updated in the long-term.

IMPACT

There is no established approach to update a TDS food list. This study provides comparative approaches to handle newly collected food consumption data for follow-on TDS activities. The results provide useful information for institutions planning or updating a TDS. Furthermore, new food consumption data for children in Germany recently became available and are here presented for the first time.

A mycotoxin-dedicated total diet study in the Netherlands in 2013: Part I – Design

A mycotoxin-dedicated total diet study (mTDS) allowing assessment of occurrence and dietary exposure to these substances was developed and carried out in the Netherlands in 2013. First, literature was searched to establish the occurrence profile of mycotoxins. Next, foods as consumed according to the Dutch National Food Consumption Surveys (DNFCS) for young children and persons aged 7-69 years, categorised in several food categories, were ranked according to their summed consumption. Subsequently, foods with the highest consumptions were included to cover >85% of the consumption of a particular food category. In some cases, foods other than those contributing to the upper 85% consumption within a food category were included based on their expected high mycotoxin contamination. In some other cases, foods not contributing to mycotoxin exposure were excluded. This resulted in 130 foods to be included in this mTDS. Since a sample size of 12 was established per food, 1,560 food items were purchased for the population aged 7-69 years. Fifty seven additional food items were purchased to take into account the different consumption profile of young children. The 1,617 food items were prepared as consumed based on information available in the food consumption surveys. The prepared food items were combined according to the different consumption forms of the 130 selected foods (e.g. fresh, canned or frozen). This resulted in 213 subsamples, which were proportionally to their consumption further pooled into 88 composite samples. These composite samples covered 87 and 88% of the amount foods consumed by young children and the population aged 7-69 years, respectively. This design allows analysis of mycotoxin occurrence and the subsequent exposure assessment using aggregated food categories reflected by the 88 composite samples, as well as a more refined approach by analysing 213 subsamples.

Exposure assessment within a Total Diet Study: a comparison of the use of the pan-European classification system FoodEx-1 with national food classification systems

A Total Diet Study (TDS) consists of selecting, collecting and preparing commonly consumed foods purchased at retail level and analysing them for harmful and/or beneficial chemical substances. A food classification system is needed to link food consumption data with the contaminant concentration data obtained in the TDS for the exposure assessment. In this study a comparison was made between the use of a national food classification systems and the use of FoodEx-1, developed and recommended by the European Food Safety Authority (EFSA). The work was performed using data of six European countries: Belgium, Czech Republic, France, The Netherlands, Spain and the UK. For each population, exposure to contaminant A (organic compounds) and/or contaminant B (inorganic compound) was assessed by the Monte Carlo Risk Assessment (MCRA) software using the national classification system and FoodEx-1 for food consumption data and for TDS laboratory results. Minimal differences between both approaches were observed. This observation applied for both contaminant A and contaminant B. In general risk assessment will be similar for both approaches; however, this is not guaranteed. FoodEx-1 proved to be a valuable hierarchic classification system in order to harmonise exposure assessment based on existing TDS results throughout Europe.