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<p>This TDS involves the purchase of 138 categories of foods, from 24 locations across the UK to give a total of 3312 individual samples. The 138 categories are then further pooled into 28 food groups.</p>
<p>Sample preparation: Each individual sample is firstly prepared for consumption (where required) based on information from the UK’s National Diet and Nutrition Survey and manufacturer’s preparation and cooking instructions. Equal quantities of the 24 individual samples in each category are then combined to form the category sample. The 138 categories are then further pooled into 28 food groups. The relative proportion of the different categories within a group reflects its importance in the average UK household diet. This is based on three previous years of food purchase data from the Family Food Survey (previously the National Food Survey). For instance, for the milk group, more semi-skimmed/skimmed milk is included than whole milk as it makes a larger contribution to the average diet.</p>
<p>Sample analyses: Both the 138 categories and 28 groups will be analysed for the following elements. Analysing both the categories and groups will allow much more specific information to be obtained than in previous TDSs.</p>
<ul>
<li>aluminium</li>
<li>antimony</li>
<li>arsenic (total and inorganic)</li>
<li>barium</li>
<li>bismuth</li>
<li>cadmium</li>
<li>chromium</li>
<li>copper</li>
<li>germanium,</li>
<li>indium</li>
<li>iodine</li>
<li>lead</li>
<li>manganese</li>
<li>mercury</li>
<li>molybdenum</li>
<li>nickel</li>
<li>palladium</li>
<li>platinum</li>
<li>rhodium</li>
<li>ruthenium</li>
<li>selenium</li>
<li>strontium</li>
<li>thallium</li>
<li>tin</li>
<li>zinc</li>
</ul>
<p>All groups will be analysed for acrylamide along with those categories in which it is expected to be present. Selected groups and categories will be analysed for a selection of 18 different mycotoxins, based on those foods in which they are expected to be present.</p>
<p>Background: The key principle of a TDS is that it is representative of the whole diet. A TDS is different from many surveys as all foods are firstly prepared for consumption, rather than being analysed as sold, before being pooled into groups before analyses. The total diet study is designed so that commodities known to be susceptible to contamination (eg offal, fish) are kept separate, as are foods that are consumed in large quantities (eg bread, potatoes, milk). </p>