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

A Total Diet Study (TDS) consists of selecting, collecting and analysing commonly consumed foods to obtain concentration data of different chemical compounds in foods as eaten. A TDS food list summarises the most consumed foods and represents the dietary habits of the general population of the country under study. The work reported here investigated whether TDS food lists that were initially designed for the whole population of the country under study also sufficiently cover the dietary pattern of specific subpopulations that are extra vulnerable for certain contaminants. The work was performed using data of three European countries: the Czech Republic, France and the UK. Each national food consumption database was combined with the corresponding national TDS food list (containing 336, 212 and 119 food items for the Czech Republic, France and the UK, respectively). The data were aggregated on the highest level of hierarchy of FoodEx-1, a pan-European food classification system, including 20 main FoodEx-1 groups. For the group ‘milk and dairy products’, the coverage of the consumption by the food list was investigated for more refined subgroups. For each food group or subgroup and country, the average percentage of coverage of the diet by the national TDS food list was calculated for different subpopulations, including children versus adults, women versus men, vegetarians versus non-vegetarians, and women of child-bearing age versus older women. The average diet of the different subpopulations was sufficiently covered by the food list of the Czech Republic and France. For the UK the average coverage was low due to a different food-coding approach and because food lists were not derived directly from national food consumption data. At the level of the 20 main food groups, differences between the subpopulations with respect to the average coverage of consumption by the TDS food list were minimal. The differences were more pronounced when looking in detail at the coverage of the dairy consumption. TDS food lists based on the mean consumption of the general population are also applicable to study the chemical exposure of different subpopulations, e.g. children, women of child-bearing age and vegetarians. This lowers the effort when performing a TDS.     

Core food of the French food supply: second Total Diet Study

As first described in the 1980s, the core food intake model allows a precise assessment of dietary nutrient intake and dietary exposure to contaminants insofar as it reflects the eating habits of a target population and covers the most important foods in terms of consumption, selected nutrient and contaminant contribution. This model has been used to set up the sampling strategy of the second French Total Diet Study (TDS) with the aim of obtaining a realistic panorama of nutrient intakes and contaminant exposure for the whole population, useful for quantitative risk assessment. Data on consumption trends and eating habits from the second French individual food consumption survey (INCA2) as well as data from a 2004 purchase panel of French households (SECODIP) were used to identify the core foods to be sampled. A total of 116 core foods on a national scale and 70 core foods on a regional scale were selected according to (1) the consumption data for adults and children, (2) their consumer rates, and (3) their high contribution to exposure to one or more contaminants of interest. Foods were collected in eight French regions (36 cities) and prepared ‘as consumed’ to be analysed for their nutritional composition and contamination levels. A total of 20 280 different food products were purchased to make up the 1352 composite samples of core foods to be analysed for additives, environmental contaminants, pesticide residues, trace elements and minerals, mycotoxins and acrylamide. The establishment of such a sampling plan is essential for effective, high-quality monitoring of dietary exposure from a public health point of view.     

A harmonised approach for identifying core foods for total diet studies

Total diet studies (TDS) are used to gather information on chemical substances in food, thereby facilitating risk assessments and health monitoring. Candidate foods for inclusion in a TDS should represent a large part of a typical diet to estimate accurately the exposure of a population and/or specific population groups. There are currently no harmonised guidelines for the selection of foods in a TDS, and so the aim of this study was to explore the possibility of generating a harmonised approach to be used across Europe. Summary statistics data from the European Food Safety Authority’s (EFSA) Comprehensive Food Consumption Database were used in this research, which provided data from national food consumption surveys in Europe. The chosen methodology for the selection of foods was based on the weight of food consumed and consumer rate. Using the available data, 59 TDS food lists were created, representing over 51 000 people across 17 countries and seven population groups. All TDS food lists represented > 85% of the populations’ diets (85.9–96.3%), while the number of foods in the TDS food lists ranged from 15 to 102. Comparison of the TDS food lists indicated that the most commonly consumed foods included wheat bread and rolls, pastries and cakes, tomatoes, apples, bananas, and chicken, while cow’s milk, tap water and orange juice were the most commonly consumed beverages across Europe. This work was complete to support EFSA and other institutions in the development of harmonised TDS into the future.     

Assessment of infant exposure to food chemicals: the French Total Diet Study design

As part of the previous French Total Diet Studies (TDS) focusing on exposure to food chemicals in the population aged 3 years and older, the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) launched a specific TDS on infants to complete its overall chemical food safety programme for the general population. More than 500 chemical substances were analysed in food products consumed by children under 3 years old, including nutrients, several endocrine disruptors resulting from human activities (polychlorinated biphenyls, dioxins and furans, brominated flame retardants, perfluoroalkyl acids, pesticide residues, etc.) or migrating from food contact materials such as bisphenol A or phthalates, but also natural substances such as mycotoxins, phytoestrogens and steroids. To obtain a representative and general view of infant food consumption, food items were selected based on results of a national consumption survey conducted specifically on this population. Moreover, a specific study on food was conducted on 429 households to determine which home-cooking practices are employed to prepare food consumed by infants. Overall, the targeted chemical substances were analysed in more than 450 food samples, representing the purchase and home-cooking practices of over 5500 food products. Foods included common foods such as vegetables, fruit or cakes as well as specific infant foods such as infant formula or jarred baby food. The sampling plan covered over 80% of the total diet. Specificities in infant food consumption and habits were therefore considered to define this first infant TDS. This study, conducted on a large scale and focusing on a particularly sensitive population, will provide accurate information on the dietary exposure of children under 3 years to food chemicals, especially endocrine disruptors, and will be particularly useful for risk assessment analysis under the remit of ANSES’ expert committees.     

中国总膳食研究三十年之演变

总膳食研究是世界卫生组织极力推荐成员国评估某个国家和地区在不同人群组对于膳食中化学危害物暴露量和营养素摄入量的最经济、有效、可靠的方法。中共中央和国务院于2019年5月9日发布《关于深化改革加强食品安全工作的意见》将开展总膳食研究作为实施风险评估和标准制定专项行动的基础性工作,来完善风险评估基础数据库。本文从中国总膳食研究的意义、启动、发展与定型的历史演变过程解读这30年的发展历程,并对其在食品安全暴露科学中的作用进行述评。     

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

Total diet studies (TDS) are recognised as a cost-effective approach in estimating dietary exposure to chemicals in food. It has been advised that candidate foods for inclusion in TDS analysis should represent a large part of the typical diet to estimate accurately the exposure of a population group. To date a variety of approaches have been used to determine which foods should be included in a core TDS food list, with no agreed method. Therefore, the aim of this study was to compare four of these approaches by creating TDS food lists for adult populations in Europe using summary statistics data from the EFSA Comprehensive Food Consumption Database. Both a food group approach and a total diet approach were employed, and foods were selected for inclusion in the TDS food lists if they met the criteria as defined by consumption weight and/or a 5% consumer rate. Using all four approaches the representation of the diet across the TDS food lists was > 85%. The food group approach showed a slight advantage in diet representation, but produced considerably longer TDS food lists in comparison with the total diet approach. The addition of a 5% consumer rate to both approaches had little impact on results. In conclusion, the total diet approach may act as a more cost-effective approach in comparison with the food group approach while still achieving comprehensive results in the creation of core TDS food lists.     

Design and preparation of market baskets of European Union commercial baby foods for the assessment of infant exposure to food chemicals and to their effects

The assessment of acute and chronic dietary exposure to contaminants in baby foods is needed to ensure healthy infant growth. Monthly European Union market baskets of commercial baby foods were designed for the first 9 months of life by the ‘babyfood’ study group of the CASCADE Network of Excellence for the specific purpose of assessing exposure to potentially toxic substances in infants fed with such foods. The present paper reports the different steps that led to the preparation of monthly pooled samples of commercial baby foods (‘Infant formulae and follow-on formulae’ and ‘Other baby foods’) that may constitute the extreme case of the diet for an infant who would not be breast fed at all. Several market baskets were generated for an ‘average European Union infant’ and for infants of four selected countries (Italy, Sweden, Spain, and the Slovakia), fed with either milk infant formulae, soy infant formulae or hypoallergenic infant formulae and weaned (at the fifth month) with commercial baby foods and beverages available on the European Union market. Market share data for 2007 for baby foods were used to design the baskets. Holding companies and the name of all their products were identified. Monthly diets for European Union infants were elaborated in terms of food categories (e.g. infant cereals) of typologies of products (e.g. infant cereals without gluten) and of a specific product. The number of baskets generated was 30 for ‘Infant formulae and follow-on formulae’ (including 62 products) and 13 for ‘Other baby foods’ (including 35 products). These market baskets were designed to be used for the determination of certain contaminants and nutrients in the diet of European Union infants and for the assessment of their effects on infant health.     

Proceedings of the workshop on food-consumption surveys in developing countries: general approaches to estimation of dietary exposure to contaminants

The initial steps in estimating dietary exposure to contaminants include gathering the necessary expertise, clarifying the intent and purpose of the work, selecting a dietary exposure model, and gathering available pertinent information. Expertise is generally needed in chemistry, agriculture, toxicology, statistics, nutritional epidemiology, and computer software development. The goal might be to determine the average exposure of a population to contaminants, to identify demographic groups within a population that are especially vulnerable to a contaminant, to evaluate the regulation of agricultural and food-manufacturing practices, or to determine compliance with standards for local and/or imported foods. Examples of dietary exposure models include the core food model, directed core food model, large database model, raw agricultural commodity (RAC) model, regional diet model, duplicate diet model, and total diet composite model. Each model has advantages and disadvantages and different costs and resource requirements. Consideration of the sources and flow of selected contaminants though the food supply may help identify the best exposure model to use. Pertinent information that may already be available includes analytical data on contaminants in foods or commodities, government regulations pertaining to the levels of contaminants in foods, food-consumption data, data on the average body weights of age-gender groups (to express exposure on a body weight basis), and biochemical measures of contaminants or their residues/metabolites. Collecting available information helps to clearly define what critical information is missing so that the planned research can be most effective. Careful documentation of decisions and assumptions allows for recalculating exposure estimates with the same model using different decisions and assumptions; documentation also allows others to understand what was done and how to use the resulting intake estimates properly. Clearly identifying the limitations of the exposure model may provide justification for additional resources to further refine and improve the model.     

Core foods of the US food supply

The core food dietary intake/exposure model may be used to assess the average intake of nutrients, contaminants and other food components by a population group and various subgroups of the population. The core food model is a mechanism that allows for the selection of the most important foods in a population's food supply so that these foods can be obtained and analysed in the laboratory. The core foods for a population change over time as food consumption patterns are altered by changes in the food supply and/or changes in the demographics of the population. Core foods of the US diet were selected using food consumption data from the 1994-96 US Department of Agriculture (USDA) Continuing Survey of the Food Intake of Individuals (CSFII). The 304 core foods were identified by placing the 5722 foods consumed by survey participants into about 300 groups. The groupings were based on food type, food use and similarity of nutrient composition. The foods within each grouping were ranked in terms of frequency of use and weight of intake, and one food item within each group was selected to become a core food and represent its group. In the model, each core food assumes the full dietary intake (by weight) for all the foods in its group. Daily mean intakes of the 304 selected core foods are presented for women and men of 19-30 years of age. If the food components of interest to investigators using this model are found in selected foods or food types, then only these foods need be analysed. The list of 304 core foods may be shortened by further aggregation to match the needs of different investigators. For example, limited data on food composition may warrant use of a shorter core food list. A shortened food list with average daily intakes of 78 core foods for women and men of 19-30 years of age is provided as an example.     

Dietary exposure estimates of isoflavones from the 1998 UK Total Diet Study.

The phyto-oestrogen contents of the 1998 UK Total Diet Study (TDS) food group composites were determined. Each TDS set consisted of composite samples, one for each of the 20 designated food groups. These composites then represented the average consumption of all the individual food elements in each group, processed into the form in which they were consumed. In the TDS, individual composites of the bread, processed meat and fish food groups contained >5 mg kg(-1) of the individual isoflavones (daidzein, genistein and glycitein). Individual composites from the groups, miscellaneous cereals, other vegetables, fruit products and nuts contained >1 mg kg(-1). After weighting for average consumption of food from each TDS food group, an estimated daily intake of 3 mg day(-1) of combined isoflavone aglycones was obtained from the TDS sample collection model for the average (adult) consumer. The UK dietary intake of phyto-oestrogens is higher than previously estimated due in part to the use of soya in processed foods.     

Probabilistic modelling to assess exposure to three artificial sweeteners of young Irish patients aged 1–3 years with PKU and CMPA

The choice of suitable normal foods is limited for individuals with particular medical conditions, e.g., inborn errors of metabolism (phenylketonuria – PKU) or severe cow’s milk protein allergy (CMPA). Patients may have dietary restrictions and exclusive or partial replacement of specific food groups with specially formulated products to meet particular nutrition requirements. Artificial sweeteners are used to improve the appearance and palatability of such food products to avoid food refusal and ensure dietary adherence. Young children have a higher risk of exceeding acceptable daily intakes for additives than adults due to higher food intakes kg^–1 body weight. The Budget Method and EFSA’s Food Additives Intake Model (FAIM) are not equipped to assess partial dietary replacement with special formulations as they are built on data from dietary surveys of consumers without special medical requirements impacting the diet. The aim of this study was to explore dietary exposure modelling as a means of estimating the intake of artificial sweeteners by young PKU and CMPA patients aged 1–3 years. An adapted validated probabilistic model (FACET) was used to assess patients’ exposure to artificial sweeteners. Food consumption data were derived from the food consumption survey data of healthy young children in Ireland from the National Preschool and Nutrition Survey (NPNS, 2010–11). Specially formulated foods for special medical purposes were included in the exposure model to replace restricted foods. Inclusion was based on recommendations for adequate protein intake and dietary adherence data. Exposure assessment results indicated that young children with PKU and CMPA have higher relative average intakes of artificial sweeteners than healthy young children. The reliability and robustness of the model in the estimation of patient additive exposures was further investigated and provides the first exposure estimates for these special populations.     

Risk assessment of dietary exposure to aluminium in the Chinese population

In order to address the issue of excessive intake of aluminium (Al) from Al-containing food additives in the Chinese diet, this study conducted a dietary exposure assessment of Al in the general population based on the national surveillance data of Al content in foods and national food consumption data. It was found that the mean dietary exposure of the whole Chinese population to Al from Al-containing food additives was 1.795 mg kg^?1 bw week^?1, not exceeding the PTWI, while high dietary exposures (e.g., 97.5^th percentile) to Al were 7.660 and 2.103–2.903 mg kg^?1 bw week^?1 for children, respectively, both exceeding the PTWI. It was found that the dietary exposure to Al for 32.5% of the total Chinese population and 42.6% of children aged 4–6 years exceeded the PTWI. Wheat flour and wheat-based products are the main source of dietary A l exposure (85% of the total intake); and puffed foods are the major source of Al intake for children. These findings suggested that consumption of Al-containing food additives could be a health concern for consumers with high food consumption (97.5^th percentile) and children under the age of 14 years.     

US Food and Drug Administration's Total Diet Study: intake of nutritional and toxic elements, 1991-96

The Food and Drug Administration (FDA) has conducted the Total Diet Study (TDS) annually since 1961. The TDS is designed to monitor the US food supply for levels of toxic chemical contaminants (pesticide residues, industrial chemicals and toxic elements) and nutritional elements. Foods are generally collected four times a year, once from each of four regions of the country. The foods are prepared table-ready before being analysed. From the results of the TDS, dietary intakes of these analytes are estimated for selected age- sex groups in the US population. This paper reports on the dietary intake of 10 nutritional and four toxic elements based on measurements made in foods collected in the TDS between 1991 and late 1996. Average daily intakes were estimated for 14 age-sex groups in the US population, as well as the contribution of specific food groups to total intakes. For most nutritional elements, teenage boys and adult males had the highest daily intakes. Intakes by infants were below the intake references for seven of 10 nutritional elements, and young girls and women had inadequate intakes of at least half the nutritional elements. Intakes by children between 2 and 10 years of age, teenage boys, and adult males met or exceeded the reference intakes for the majority of nutritional elements. Intakes by all population groups were well below the reference intakes for all toxic elements.     

Occurrence of toluene in Canadian total diet foods and its significance to overall human exposure

Levels of most VOCs in foods are usually low because of their volatility, and human exposure to VOCs is expected to be mainly via inhalation of ambient and indoor air. However, dietary exposures to VOCs can be significant to overall exposures if elevated concentrations of VOCs are present in foods consumed in high amounts and/or on a regular basis, and this was demonstrated in this study with the occurrence data of toluene from the recent 2014 Canadian Total Diet Study (TDS). Concentrations of toluene in the composite samples of most food types from the 2014 TDS are low and similar to the results from the previous 2007 TDS with some exceptions, such as beef steak (670 ng/g (2014 TDS) vs. 14 ng/g (2007 TDS)), poultry, chicken and turkey (307 ng/g (2014 TDS) vs. 8.8 ng/g (2007 TDS)). Toluene concentrations in most of the grain-based and fast food composite samples from the 2014 TDS are considerably higher than those from the 2007 TDS, with the highest level of 4655 ng/g found in the composite sample of crackers from the 2014 TDS (compared to 18 ng/g from 2007 TDS). Dietary exposure estimates for toluene based on the occurrence results from the 2014 TDS show that for most of the age groups, grain-based foods are the primary source, accounting for an average of 77.5% of the overall toluene intake from the diet. The highest dietary exposures to toluene were observed for the adult age groups, with estimated average exposures ranging from 177.4 to 184.5 µg/d. Dietary exposure estimates to toluene are well below oral doses associated with toxicological effects and also below the maximum estimated intake (819 µg/d) from air inhalation for adult group (20 – 70 years) based on the results from CEPA (Canadian Environmental Protection Act) assessment in 1992.     

Dietary exposure to aluminium of urban residents from cities in South China

A dietary survey was conducted over three consecutive days by using 24-hour dietary recall in the Pearl River Delta of South China to investigate the dietary consumption status. A total of 1702 food samples, 22 food groups, were collected, and aluminium concentrations of foods were determined by using ICP-MS. Weekly dietary exposure to aluminium of the average urban residents of South China was estimated to be 1.5 mg kg^?1 body weight, which amounted to 76% of the provisional tolerable weekly intake. Wheat-made products (53.5%) contributed most to the dietary exposure, followed by vegetables (12.2%). The high-level consumers’ weekly exposure to aluminium was 11.1 mg kg^?1 body weight, which amounted to 407% of the provisional tolerable weekly intake. The results indicated that the general urban residents in South China might be safe from aluminium exposure, but the high-level consumers might be at some risk of aluminium exposure. The foods contributing to aluminium exposure were processed food with aluminium-containing food additives. It is necessary to take effective measures to control the overuse of aluminium-containing food additives.     

Future perspectives in Orbitrap™-high-resolution mass spectrometry in food analysis: a review

A literature search from 2007 to 2014 was conducted to identify publications where principally LC-Orbitrap?-high-resolution mass spectrometry (HRMS) has been employed in food analysis. Of a total of 212 relevant references, only 22 papers were from 2007–10, but in subsequent years there has been a steady growth in publications with 38–55 relevant papers being published each year from 2011 to 2014. In the food safety area, over 50% of the published papers were equally divided between pesticides, veterinary drug residues and natural toxins (including mycotoxins) focused primarily on multi-analyte target analysis. LC-Orbitrap-HRMS was also found to be increasingly important for the analysis of bioactive substances, principally phenolic compounds in foods. A number of studies reported for the first time the identification of new fungal metabolites, predominantly various conjugated forms of known mycotoxins. Novel process contaminants were also identified by LC-Orbitrap-HRMS, as were various substances used for food adulteration and bioactive substances in herbal products and dietary supplements. Untargeted analysis is seen as a major future trend where HRMS plays a significant role. Retrospective analysis of scanned high-resolution mass spectra in conjunction with relevant databases can provide new insights. Metabolomics is also being increasingly used where foods are being profiled through fingerprinting using HRMS. All evidence points towards future growth in the number of applications of HRMS in food safety and quality, as the power of this technique gains wider recognition.     

Dietary exposure to cadmium of Shenzhen adult residents from a total diet study

Cadmium (Cd) contamination has become a public health concern in recent decades. The aim of the present study was to assess the contribution of dietary Cd exposure and its health risk among Shenzhen adult residents using the Total Diet Study (TDS) approach. Cd was determined in 13 food groups using 276 individual samples by ICP-MS. The major food contributors to Cd exposure of Shenzhen adult residents were ‘Vegetables’ (32.6% of the total exposure), ‘Rice and its products’ (19.2% of the total exposure) and ‘Fish, seafood and shellfish’ (18.5% of the total exposure). The mean and the 95th percentile dietary exposure to Cd of Shenzhen adults were 9.9 and 13 μg kg^?1 bw month^?1, respectively. The dietary exposures of all individual age-gender population subgroups were below the provisional tolerable monthly intake (PTMI = 25 μg kg^?1 bw month^?1), so the health risk of Cd dietary exposure of Shenzhen adults is considered to be low, but still, cadmium pollution should be strictly controlled and monitored continuously due to an exceptionally long biological half-life of cadmium.     

Estimate of dietary exposure to sulphites in child and adult populations in the Basque Country

Sulphites are widely used as a preservative and antioxidant additive in food. The aim of this study was to assess dietary sulphite intake in adults aged 35–65 years and in children aged 4–18 years living in the Basque Country, northern Spain. We determined sulphite concentrations in 909 samples covering 16 food types. The maximum permitted levels were exceeded in 17% of samples. Making recommended assumptions for non-quantifiable results, estimates of mean lower and upper bounds were calculated for sulphite concentrations in each food type. These sulphite data were combined with consumption data derived from 8417 adults from the European Prospective Investigation in Cancer and Nutrition cohort in Gipuzkoa, recruited in 1992–1995 using a diet history method, and 1055 children from the Basque Country Nutrition Children Survey, conducted in 2004–2005 using two 24-h recall questionnaires to assess diet. The results were compared with the acceptable daily intake (ADI) proposed by the Joint Expert Committee on Food Additives (JECFA). The mean dietary exposure to sulphites was 0.08 mg kg^?1 bw day^?1, only 11% of the ADI in the overall group of children (4–18 years old), but the acceptable intake was exceeded by 4% of 4–6 year olds. For the adults (35–65 years old), the mean dietary exposure was 0.31 mg kg^?1 bw day^?1, 45% of the ADI, but the acceptable intake was exceeded in 14.6% of cases. The major contributing foods were minced meat and other meat products for children and wine for adults.