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.