Establishing a food list for a Total Diet Study: how does food consumption of specific subpopulations need to be considered?

Singapore's Total Diet Study (2021-2023): Study Design, Methodology, and Relevance to Ensuring Food Safety

A total diet study is often used to evaluate a population's baseline dietary exposure to chemical hazards from across the diet. In 2021-2023, Singapore carried out a TDS, and this article presents an overview of the study design and methodological selections in Singapore's TDS, as well as its relevance to ensuring food safety. A food consumption survey was conducted on Singapore citizens and permanent residents, where food consumption patterns of the Singapore population were identified. The selection of chemical hazards and foods for inclusion in Singapore's TDS, as well as principal considerations on sampling, food preparation, and analytical testing are discussed. Commonly consumed foods by the Singapore population in food categories such as grain and grain-based products, meat and meat products, fish and seafood, vegetables, fruits, milk and dairy products were included in this study, and mean concentrations of chemicals tested in each food category were reported, with food categories possessing higher levels identified. Future work will include dietary exposure assessments for the population and analysis of the contributions by food and cooking method.

The first harmonised total diet study in Portugal: Planning, sample collection and sample preparation

The first Total Diet Study (TDS) was carried out in Portugal using harmonised procedures developed under the TDS-Exposure project. This publication describes in detail the TDS planning, sample collection and preparation, filling a gap found in literature. TDS food list (1070 items) by food group for 18-74 years olds was derived using 24 h recall food consumption survey data. Of the 164 TDS samples defined based on FoodEx2, the most represented belonged to 'Composite dishes' (21%) and 'Fish and Fish products' (15%). A total of 227 TDS samples (12 subsamples each), were collected (2014-2016) in Greater Lisbon region as 126 'national', 17 'regional non-seasonal' and 21 'regional seasonal'. Seasonal samples were mostly fruits, vegetables and some fish. Subsamples were prepared as consumed, pooled, homogenised and stored at -18 °C. The harmonised procedures used allow comparison of exposure assessment with other countries and evaluation of exposure trends if TDS are used.

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.