Case study based on: EFSA (European Food Safety Authority), Arcella D., Gerlova, P., Innocenti, M.L., & Steinkellner, H. (2017). Scientific report on human and animal dietary exposure to T-2 and HT-2 toxin. EFSA Journal.
Food security is a multidimensional concept that includes food safety as one dimension (Coates, 2013). Food safety indicators are critical for surveillance throughout the value chain, from production, to trade and consumption (Chan, 2014). Dietary exposure assessment is a critical component of assessing risk of food contamination by microbiological or chemical agents (FAO/WHO, 2009; EFSA, 2011a).
The following case study, based on work by European Food Safety Authority (EFSA) et al. (2017), illustrates an example of combining food consumption with chemical occurrence data to calculate dietary exposure to mycotoxins in humans and livestock in European countries. According to the World Health Organization, mycotoxins are “toxic compounds naturally produced by certain types of molds (fungi)” (WHO, 2019). These molds can infect agricultural commodities in the field or during storage and can be found in cereals, dried fruits, nuts, and spices (WHO, 2019). Not only do mycotoxins pose a direct acute risk to human health, but chronic exposure has also been linked to poor growth and nutrition outcomes (Smith et al., 2015; Watson et al., 2017). The following paragraphs summarize the methods and findings from EFSA et al. (2017) and highlight the strengths and weaknesses of using chronic food consumption and acute food consumption, derived from 24-hour Dietary Recall (24HR)and food records, to assess dietary exposure to mycotoxins (T-2 and HT-2).
The authors drew on the EFSA Comprehensive European Food Consumption Database (“Comprehensive Database”) for their analyses of food consumption and chemical contaminant occurrence data (i.e. data on the presence of contaminants and chemical residues in different food products and feed). The food consumption data in the Comprehensive Database is a compilation of existing national dietary surveys of individual level food consumption, carried out in most European countries, covering 94,532 individuals (infants, toddlers, adolescents, adults, and elderly). Data for this database were collected using single or repeated 24HRs or 48HRs or food records covering from three to seven days per person. Food consumption data were categorized and matched to occurrence data according to the FoodEx classification system (EFSA, 2011b). FoodEx is a food classification system originally designed by EFSA to “facilitate the assessment of dietary exposure to hazardous chemicals by allowing accurate matching of the data sets on chemical occurrence and food consumption” (EFSA, 2011b). Now called FoodEx2, this classification approach has been adopted by several global initiatives with the aim of harmonizing food consumption data worldwide for a wide range of applications including, but not limited, to food safety [see the FAO-WHO Global Individual Food Consumption Tool (FAO/WHO GIFT), International Dietary Data Expansion Project (INDDEX), and the Global Dietary Database (GDD)]. The chemical contaminant occurrence data in the Comprehensive Database were available from 25 European countries.
The study assessed chronic dietary exposure and acute dietary exposure to individual T-2 and HT-2 and to the sum of T-2 and HT-2. To assess chronic dietary exposure, dietary surveys with at least two non-consecutive reporting days. These data, along with individual respondent body weights, were available through the database from 35 dietary surveys from 19 European countries. Occurrence data and food consumption data were linked using FoodEx coding, at the most granular possible level (i.e. either at Level 1, a broad FoodEx2 category such as “Grains and grain-based products”, or at Level 2, representing a more detailed set of food descriptors within the broad category, such as “Breakfast cereals”, “Pasta”, and “Bread and rolls”). Next, individual average exposures per day and body weight were obtained for all individuals in the data set and expressed as nanograms/kilogram body weight/day. These data were used to compute mean and 95th percentile exposures by survey and age group.
To estimate acute dietary exposure to T-2 and HT-2, the authors considered dietary surveys with only one reporting day, available from 41 dietary surveys from 23 European countries. Acute dietary exposure was expressed as the product of the total amount consumed by food category for each reporting day per kilogram of body weight and the occurrence level that was generated probabilistically from modeling the occurrence levels across the surveys.
The findings showed that both chronic and acute dietary exposure to T2 and HT2 was significantly higher among infants and toddlers than adults. Across all age categories, consumption of “grains and grain-based products” was responsible for the highest mean chronic dietary exposure to T-2 and HT-2 of any food group. More specifically, “cereal flakes” played the greatest role in overall exposure among infants (84%) and toddlers (79%), while “fine bakery wares” had the highest contribution in the elderly (53%). “Snack food” was found to be an important contributor for adolescents (45%). The food category that contributed most to acute dietary exposure was “Bread and rolls”. Other categories with important contributions to acute exposure were “fine bakery wares”, “cereal flakes” and “cereal-based food for infants and young children”.
This case study is an example of how food consumption and chemical occurrence data in food can be used to estimate acute and chronic dietary exposure when individual-level quantitative dietary data are available. The quantified individual-level data allow experts to assess the risk of dietary exposures of a range of contaminants in different population groups. This type of analysis was feasible due to the fact that EU member states regularly perform analyses of contaminants and chemicals residues in commodities destined for human consumption, following an EU mandate to EFSA to annually collect chemical contaminant occurrence data shared among a wide range of stakeholders. This type of assessment is more challenging in many low- and middle-income countries, where systematic data collection on food consumption and chemical occurrence data is, comparatively, lacking. The need for this type of assessment in LMICs is equally, if not more, important.
The surveys in the EFSA data set used a diversity of dietary assessment methods and recall periods, including 24HR and multi-day food records (also known as food diaries), though most countries in the study used food records. Although food records can provide quantitative information about individual food and nutrient intakes from many groups across multiple days to obtain a picture of usual intake, respondents need to be literate, numerate, and well-trained in order to ensure the accuracy of their recording. Also, there is an added risk of bias due to changes in participant behavior during their recording period.
The researchers took advantage of a comprehensive database of national level food consumption and chemical occurence data to study acute and chronic dietary exposure to mycotoxins in European countries. This analysis provides insight into the critical contribution of dietary data for food safety risk assessment. The findings underscore the significant chronic and acute exposures across the population, particularly the youngest, to strains of harmful mycotoxin.
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