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.     

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.     

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.     

A conceptual framework for the collection of food products in a Total Diet Study

A total diet study (TDS) provides representative and realistic data for assessing the dietary intake of chemicals, such as contaminants and residues, and nutrients, at a population level. Reproducing the diet through collection of customarily consumed foods and their preparation as habitually eaten is crucial to ensure representativeness, i.e., all relevant foods are included and all potential dietary sources of the substances investigated are captured. Having this in mind, a conceptual framework for building a relevant food-shopping list was developed as a research task in the European Union’s 7th Framework Program project, ‘Total Diet Study Exposure’ (TDS-Exposure), aimed at standardising methods for food sampling, analyses, exposure assessment calculations and modelling, priority foods, and selection of chemical contaminants. A stepwise approach following the knowledge translation (KT) model for concept analysis is proposed to set up a general protocol for the collection of food products in a TDS in terms of steps (characterisation of the food list, development of the food-shopping list, food products collection) and pillars (background documentation, procedures, and tools). A simple model for structuring the information in a way to support the implementation of the process, by presenting relevant datasets, forms to store inherent information, and folders to record the results is also proposed. Reproducibility of the process and possibility to exploit the gathered information are two main features of such a system for future applications.     

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.     

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。     

Dietary exposure of Hong Kong adults to pesticide residues: results of the first Hong Kong total diet study

The use of pesticides and other chemicals has become a common practice in modern agriculture to enhance and stabilise crop yield, protect the nutritional integrity of food, facilitate food storage to assure year-round supplies, and provide attractive and appealing food products. With the adoption of strict good agricultural practice (GAP), only minimal amounts of pesticide residues should remain on the crops or in connected foods of animal origin up the food chain. To assess their associated health risk to local people, the dietary exposure of Hong Kong adults to residues of four groups of pesticides or their metabolites – organophosphorus pesticides (OPPs), carbamates, pyrethrins and pyrethroids, and dithiocarbamate (DTC) metabolites – is estimated in the first Hong Kong Total Diet Study (TDS). A total of 150 commonly consumed food items were collected and prepared “as consumed”. A total of 600 composite food samples were analysed for 85 pesticides or their metabolites by liquid chromatography-tandem mass spectrometry (LC-MS/MS). These pesticides were primarily found at low levels (highest mean = 350 μg kg^?1) in food samples of plant origin such as vegetables and fruits. Dietary exposures to pesticide residues were estimated based on the analytical results and the food consumption data of the local residents. The estimated dietary exposures of Hong Kong adults to all individual pesticides were well below their respective acceptable daily intakes (ADIs). The percentage contributions of the estimated mean and 95th percentile dietary exposures to the ADIs of individual pesticides were <6% and <24% for the OPPs, <1% for the carbamates and pyrethrins and pyrethroids, and <1% and <4% for the DTC metabolites, respectively. The findings indicate that dietary exposures to all the pesticide residues analysed in this study were unlikely to pose unacceptable health risks to the Hong Kong population.     

Pb,Hg, Cd,As, Sb and Al levels in foodstuffs from the 2nd French total diet study

In 2006, the French Food Safety Agency (AFSSA) conducted the second French total diet study (TDS) to estimate dietary exposures of main minerals and trace elements from 1319 samples of foods habitually consumed by the French population. The foodstuffs were analysed by ICP–MS after microwave-assisted digestion. Contamination data for lead, mercury, cadmium, arsenic, antimony and aluminium were reported and compared with results from the previous French total diet study. The results are comparable with those from the rest of Europe. “Fish and fish products” and “sweeteners, honey and confectionery” were the food groups showing the highest cumulated contents in Pb, Hg, Cd, As, Al and Sb. However, observed levels remained low and were generally well below the maximum levels set by the current European regulation for lead, cadmium and mercury.     

Li, Cr, Mn, Co, Ni, Cu, Zn, Se and Mo levels in foodstuffs from the Second French TDS

In 2006, the French Food Safety Agency (AFSSA) conducted the Second French Total Diet Study (TDS) to estimate dietary exposures to the main minerals and trace elements from 1319 samples of foods typically consumed by the French population. The foodstuffs were analysed by inductively coupled plasma-mass spectrometry (ICP-MS) after microwave-assisted digestion. Occurrence data for lithium, chromium, manganese, cobalt, nickel, copper, zinc, selenium and molybdenum were reported and compared with results from the previous French TDS. The results indicate that the food groups presenting the highest levels of these essential trace elements were “tofu” (for Li, Mn, Ni, Cu, Zn and Mo),“fish and fish products” particularly “shellfish” (for Li, Co, Cu, Zn, Se and Mo), “sweeteners, honey and confectionery” particularly dark chocolate (for Cr, Mn, Co, Ni and Cu), “cereals and cereal products” (for Mn, Ni and Mo) and “ice cream” (for Cr, Co and Ni).     

Are Canned Beverages Industries Progressively Switching to Bisphenol AF?

Seven bisphenols, endocrine‐disruptor chemicals, were analytically determined for risk assessment in 52 large‐consumption beverages collected from the Italian market. The analytes under examination were bisphenol A, bisphenol F, bisphenol E, bisphenol B, bisphenol AF, bisphenol A diglycidyl ether, and bisphenol M. The concentration levels of all bisphenols detected ranged from <LOQ to 1,358 ng/mL in beers and from <LOQ to 76 ng/mL in energy drinks. The results of this monitoring study demonstrate the high presence of some congeners in beers, such as bisphenol AF, for which a European regulation is not yet available. Although the concentrations of the investigated bisphenols and that are under European regulations for migration into the food (Bisphenol A and BADGE) resulted below the legal limits in all screened beverages, the importance of their presence in foods should not be underestimated. Indeed, the safety of these analogues has not entirely been demonstrated and they could contribute to the total daily intake of endocrine disruptors, with special regards to specific demographics.     

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.     

Estimation of the dietary intake of chemicals in food

Methods for estimating the exposure of individuals to chemical substances present in the diet require information to be obtained about the patterns of food consumption in a community as well as the concentration of these chemicals in the diet. Methods of estimating food intakes using food diaries/weighed intake studies, dietary recall studies, food frequency and food disappearance methods are described. Their use, together with calculations derived from the data they provide are described to estimate normal and atypical food consumption patterns. The methods which have been used to estimate the exposure to existing chemicals in food are briefly reviewed and include total diet studies, selective studies on individual foods and duplicate portion studies. These methods are inappropriate for estimating the prospective intake of a chemical in food and the ways in which this issue may be approached, both nationally and internationally, are described with particular reference to the intakes of pesticide residues and food additives.     

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.     

Determination of Some Endocrine-Disrupting Metals and Organochlorinated Pesticide Residues in Baby Food and Infant Formula in Turkish Markets

There is a paucity of data in respect of the nutritional quality of complementary foods for infants and young children aged between 6 and 12 months. In this study, we developed and validated an analytical method for determination of the endocrine-disrupting organochlorine pesticides (OCPs) and elements (As, Cd, and Pb) in infant formula and baby foods. Therefore, it found out the contamination level of the both OCPs and some trace metals (As, Cd, and Pb) in widely consumed infant formula and baby food in Turkey. Metal concentrations in baby foods and infant formula were determined by inductively coupled plasma mass spectrometry. Samples were digested with nitric acid and hydrogen peroxide in a microwave oven. Determination of 24 organochlorine pesticide residues in baby foods and infant formula was completed by using gas chromatography double mass spectrometry. QuEChERS extraction method was carried out in the sample preparation part. The analytical performance of the entire procedure, such as linearity, the detection of limit, limit of quantification, specificity/selectivity, recovery (%), and precision, were assessed. The recoveries ranged from 93% (As) to 100% (Pb) for elements 78–98% for organochlorine pesticide residues (OCPs) at 100 ng mL^?1. According to the results, lead, cadmium, and pesticides were not detected in any of the samples, while arsenic was detected in 16 samples.     

Total diet studies: the identification of core foods in the United States food supply.

Some total diet studies are based on the selection and analysis of core foods in a national or regional food supply. One way to select core foods is by computerized evaluation of the daily food intakes reported by subjects participating in national food consumption surveys. The foods consumed by the population groups of concern may be aggregated into core food groups. The foods within each group may be ranked according to daily intake and weight percentage of the total diet. The food that best represents each group may then be identified as a core food, and the daily consumption levels for each food group may then be assigned to the core food representing the group. Consumption levels may be determined for the specific age-sex categories of concern. To assess the representativeness of core foods identified in this manner, the food composition database of the national survey may be used to determine nutrient intakes based on the full range of foods in the database versus nutrient intakes based on the core foods.     

Dietary intake of four artificial sweeteners by Irish pre-school children

In spite of rigorous pre- and post-market reviews of safety, there remains a high level of debate regarding the use of artificial sweeteners in foods. Young children are of particular interest when assessing food chemical exposure as a result of their unique food consumption patterns and comparatively higher exposure to food chemicals on a body weight basis when compared with the general population. The present study examined the intakes of four intense sweeteners (acesulfame K, aspartame, saccharin, sucralose) in the diets of children aged 1–4 years using food consumption and sweetener presence data from the Irish National Pre-school Nutrition Survey (2010–11) and analytical data for sweetener concentration in foods obtained from a national testing programme. Four exposure assessment scenarios were conducted using the available data on sweetener occurrence and concentration. The results demonstrated that the mean daily intakes for all four sweeteners were below the acceptable daily intake (ADI) (17–31%), even considering the most conservative assumptions regarding sweetener presence and concentration. High consumer intakes (P95) were also below the ADI for the four sweeteners when more realistic estimates of exposure were considered. Both sweetener occurrence and concentration data had a considerable effect on reducing the estimated intake values, with a combined reduction in intakes of 95% when expressed as a proportion of the ADI. Flavoured drinks were deemed to be a key contributor to artificial sweetener intakes in this population cohort. It was concluded that there is no health risk to Irish pre-school children at current dietary intake levels of the sweeteners studied.     

Science-based decision matrix for the identification of endocrine disruptors for regulatory purposes

Recent EU legislation for chemical substances requires a particular assessment of endocrine disrupting properties that may cause adverse effects in humans. Especially for pesticidal active substances, measures concerning specific scientific criteria for the determination of endocrine disrupting properties should have been presented by the European Commission until December 2013. But presently, no specific science-based approach for the assessment of these substances has been agreed upon. This paper is discussing common scientific principles for the evaluation and grouping of substances with endocrine disrupting properties that may cause adverse effects in humans. A matrix-based approach is proposed to be applied in various fields of scientific evaluation of chemical substances, which is based on a scientific evaluation of all available data that may contribute to ensure a high level of protection of human health. This evaluation is expected to be proportionate, consistent and predictable to support administrative decisions in regulatory toxicology. However, a scientifically based categorisation in a decision matrix as a backbone for specific and legally binding rules should be performed according to the relevant EU regulations for the aforementioned groups of substances. Considering the complexity of the matter, it appears appropriate to base possible categorisation on considerations in a decision matrix, which take into account severity, reversibility, potency and consistency of an adverse effect. Based on this decision matrix it should be possible to allocate substances falling under the WHO/IPCS definition to categorise as endocrine disruptors (EDs) or even dispense such substances from categorisation.