The Canadian total diet study design: 1992–1999

Chloroform in food samples from 2014 Canadian total diet study: occurrence and dietary exposure

Chloroform or trichloromethane is one of the trihalomethanes formed during disinfection of water with chlorine, and residues of chloroform can be detected in foods and food products due to the use of chlorinated drinking water and disinfecting food processing equipment with chlorine-based disinfectants. In this study, chloroform was detected in 37 (or 23%) of the 159 composite food samples from the 2014 Canadian Total Diet Study, but was not detected in cereals, fruits, fast foods, and most of the meat samples. Chloroform was detected in almost all 14 composite samples of dairy products, with the highest level (58 ng/g) observed in butter, followed by cream (26 ng/g), and cheese (12-21 ng/g). Chloroform was detected in tap water (23 and 29 ng/g) and most of the beverage samples, but concentrations were lower than those reported in other studies possibly due to evaporation during the preparation of the composite samples. Dietary exposures to chloroform are higher for younger age groups (0.51-1.41 µg/kg body weight/day) than for adults (0.25-0.42 µg/kg body weight/day). Drinking water contributed most to daily intakes for all age groups, accounting for between 62% and 86% of the total chloroform dietary intakes.

Trends of bisphenol A occurrence in canned food products from 2008-2020

It is known that the industry already abandoned the use of bisphenol A (BPA)-based epoxy resins as internal coatings for some canned food products (e.g. infant formula, soups). The presence of bisphenol A (BPA) in foods has also been extensively investigated, especially since late 2000. However, information on temporal trends of BPA occurrence in foods is very limited. It is not clear if BPA-based epoxy resins are still being used in internal coating for many other canned foods and if the overall exposure to BPA through consumption of canned foods has significantly decreased. As part of the Canadian total diet study (TDS) program, we have been analysing food samples for BPA since 2008. In this study, results of BPA in samples of different composite canned foods from 2008-2020 TDS were reported. Clear temporal trends were observed for canned fish and soups, with BPA levels being significantly reduced since 2014 for canned fish products and 2017 for canned soups. Temporal trends were not observed for canned evaporated milk, luncheon meats, and vegetables, with even the highest levels of BPA being detected in recent samples for evaporated milk (57 ng/g), luncheon meats (56 ng/g), and baked beans (103 ng/g). This seems to indicate that BPA-based epoxy resins are still being used in the internal coatings for these canned foods products. Thus, analysis of canned food samples for BPA should be continued for exposure assessment.

Temporal trend of bisphenol S occurrence in meat samples from 2008-2020 Canadian total diet study

In our previous study, bisphenol S (BPS) was detected unexpectedly and at high levels in meat samples from 2016 and 2020 Canadian total diet study (TDS). In this study, samples of meat and meat products from 2008-2015 and 2017-2019 TDS were also analysed to investigate the consistency of BPS occurrence in meat and identify possible trends and provide some information on the potential sources for BPS in meat. BPS was detected again with the highest levels observed in samples of fresh pork (105 ng/g) and veal cutlets (140 ng/g) from the 2008 TDS. This indicates that the occurrence of BPS in meat is not a recent phenomenon but rather an existing one since 2008 or even earlier. BPS concentrations in meat samples from the 2008 to 2020 TDS varied significantly, e.g. 1.2-118 ng/g in roast beef, 1.8-140 ng/g in veal cutlets, but no trend was observed. The lack of trend for BPS over the period of 13 years (2008-2020) does not support the speculation that BPS is being used to replace BPA in food packaging, and sources other than food packaging may be possible and should be investigated for BPS.

Bisphenol S in individual and composite meat and meat products and implication for its sources

In this study, the occurrence of bisphenol S (BPS) in the meat and meat products from a recent Canadian Total Diet Study (TDS) was investigated in more detail. In addition to their composite samples, the individual raw meat and meat products were also analysed for BPS to investigate the variations of BPS levels and provide some information on the potential sources for BPS in meat. BPS was detected in all the 11 composite samples of different meat and meat products, with the highest level in roast beef (118.23 ng/g) and lowest in cured pork (0.14 ng/g) and cold cuts luncheon meats (0.18 ng/g). BPS was also detected in all the 84 individual raw meat and meat products, with the highest level of 257.61 ng/g in roast beef, followed by 190.41 ng/g in organ meats, 110.15 ng/g in beef steak, 27.91 ng/g in veal cutlets, 17.63 ng/g in wieners & sausages, and 15.27 ng/g in ground beef. However, significant variations of BPS levels were observed in the individual meat and meat product samples under the same category collected from different stores. This may indicate that packaging is unlikely the sources for BPS in meat otherwise BPS levels would have been more or less the same with the same type of packaging (Styrofoam and cling film) regardless where they were collected. Thus, sources other than food packaging, such as the contaminated feed and farming environment (e.g. grass) for animals (e.g. cow), may be possible and should be investigated in future studies.

BMI modifies the association between dietary intake and serum levels of PCBs

Polychlorinated biphenyls (PCBs) are a group of persistent organic pollutants that are carcinogenic, neurotoxic, and endocrine disrupting in humans. Although diet is the primary source of exposure, there is no consensus on the association between dietary intake and serum PCBs. Additionally, body mass index (BMI) - with its inverse association with serum PCBs - may play a role in the association, which has never been studied. Therefore, we aimed to examine the association between dietary intake and serum levels of PCBs, and whether the association was modified by BMI. We used data from the National Health and Nutrition Examination Survey (NHANES) 2003-2004, including 1531 participants. We estimated dietary intake of PCBs using the 24-hour diet recall, USDA Food Composition Intake Database, and PCB content in foods from the Canada Total Diet Study. Serum PCBs were measured by high-resolution gas chromatography-mass spectrometry (HRGC-HRMS). We used linear regression to examine the associations of dietary PCB intake with serum levels of seven PCB congeners and six PCB metrics. Further, we explored the role of BMI in the associations. We found that participants who were older and non-Hispanic tended to have a higher serum level of ∑37-PCB. In addition, we observed positive associations between dietary intake and serum PCBs for: PCB 105, 118, 126, 138 + 158, and 153 (P value ranges 0.005-0.03); seven PCB indicators (P value = 0.03) and the sum of 37 PCBs (P value = 0.04). Furthermore, we observed an effect modification by BMI (P for interaction = 0.01 for ∑37-PCBs), with stronger associations in underweight or normal-weight individuals, and no association in overweight and obese individuals. In conclusion, within a cross-sectional, nationally representative sample of the US population, dietary PCB intake was positively associated with serum PCBs and the association was modified by BMI. Additional studies are warranted to replicate and confirm this effect modification.

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in food and human dietary intake: An update of the scientific literature

It is well established that for non-occupationally exposed populations, dietary intake is, by far, the main way of human exposure to polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-p-furans (PCDD/Fs), a family of environmental POPs with a well-known potential toxicity -including carcinogenicity-in humans. We here summarize the results of recent studies (2010-2021) (databases: Scopus and PubMed), focused on determining the levels of PCDD/Fs in food samples of different origins, as well as the dietary intake of these pollutants. We have revised studies conducted in various Asian, American and European countries. However, information is rather limited, with no recent data for most countries over the world. Due to the enormous differences in the methodologies of the studies, to conduct a detailed comparison of the results for the different regions and countries has not been possible. Notwithstanding, where data over time are available, important reductions have been observed. These reductions have been linked to the decreases in the environmental emissions of PCDD/Fs noted in recent years. Interestingly, reductions in the levels of PCDD/Fs in biological tissues are also occurring in parallel. In general, the tolerable daily/weekly/monthly dietary intakes of PCDD/Fs are not being currently exceeded where data are available.

The First Nations Food, Nutrition and Environment Study (2008-2018)-rationale, design, methods and lessons learned

OBJECTIVE

To describe the rationale, the participatory nature of the methodology, and the lessons learned during the First Nations Food, Nutrition and Environment Study (FNFNES), a community-based participatory research project implemented in eight Assembly of First Nations regions, which includes the entirety of Canada south of the 60th parallel.

METHODS

FNFNES respected the First Nations principles of Ownership, Control, Access and Possession (OCAP®) ( https://fnigc.ca/ocap ). A random sampling strategy based on an ecosystem framework comprising 11 ecozones was adopted to collect representative nutritional and environmental health results for all First Nations adults living on-reserve south of the 60th parallel. Data collection occurred during the fall months from 2008 to 2016. Respective First Nations were involved in the planning and implementation of data collection for the five principal components: household interviews, tap water sampling for metals, surface water sampling for pharmaceuticals, hair sampling for mercury, and traditional food sampling for contaminants.

RESULTS

A total of 6487 adults from 92 First Nations participated in the Study (participation rate 78%). A higher percentage of females (66%) participated than males (34%). The average age of males and females was similar (44 and 45 years, respectively). This study offers a novel body of coherent and regionally representative evidence on the human dimension of the ongoing environmental degradation affecting First Nations.

CONCLUSION

FNFNES serves as a good example of participatory research. We encourage public health professionals to develop policy and programs building on the participatory dimension of the research as well as on its results. The information collected by the FNFNES is also important for community empowerment, environmental stewardship and the general promotion of good health by and for First Nations peoples in Canada.

Occurrence of 30 trace elements in foods from a multi-centre Sub-Saharan Africa Total Diet Study: Focus on Al, As, Cd, Hg, and Pb

This paper reports occurrence data related to 30 trace elements in food composite samples from a multi-regional Sub-Saharan Africa Total Diet Study. Herein, 2700 samples grouped in 225 food composite samples corresponding to 13 food groups: cereals, tubers, legumes, vegetables, fruits, nuts/seeds, meat, eggs, fish, milk/dairy, oil/fats, and beverages from eight locations in four countries, namely Benin (Littoral/Borgou), Cameroon (Duala/North), Mali (Bamako/Sikasso), and Nigeria (Lagos/Kano) were prepared as consumed, pooled, and analysed using a validated method based on inductively coupled plasma-mass spectrometry. The occurrence data for Al, As, Cd, Hg, and Pb as regulated by the Codex Alimentarius are discussed herein. Although the levels of As, Cd, Hg, and Pb were above the limit of quantification, they were below the maximum limits set by the Codex in most samples analysed. A distinct feature was observed for cereals and tubers, as they were mostly contaminated with Al and Pb. A pilot study regarding the impact of using artisanal cookware (made from recycled aluminium) on the contamination of food samples was performed. Relevant contamination with Al and Pb when cooking tomato samples from Cameroon and Nigeria using artisanal aluminium cookware was compared to that when cooked using stainless-steel.

p-Cymene, a natural antioxidant, in Canadian total diet foods: occurrence and dietary exposures

BACKGROUND

There is a lack of information on the presence of volatile organic compounds including p-cymene in foods for dietary exposure assessment. p-Cymene is a monoterpene found in many plant species, which has been used as a flavouring agent in foods and also exhibits antioxidant and antimicrobial properties. While the Joint FAO/WHO Expert Committee on Food Additives (JECFA) has no safety concerns at current levels of intake when used as a flavouring, the current study examines p-cymene levels in foods in general, not just from possible uses as a flavouring, as there could still be a potential health concern if there were high levels of exposure.

RESULTS

159 food composite samples from the 2014 Canadian Total Diet Study were analysed for p-cymene using a gas chromatographic-mass spectrometric method after headspace solid-phase microextraction. Concentrations of p-cymene in the composite samples of most food types were generally low, with a maximum level of 73.5 μg g^-1 , detected in the composite sample of herbs and spices. Dietary exposures to p-cymene were estimated for different age groups of Canadian populations.

CONCLUSIONS

Although p-cymene was detected in various foods, estimated dietary exposures to p-cymene for different age groups are well below the human intake threshold of toxicological concern established by JECFA of 1800 μg per person per day for structural class I flavours, which includes p-cymene. © 2019 Society of Chemical Industry.

Occurrence of 13 volatile organic compounds in foods from the Canadian total diet study

Volatile organic compounds (VOCs) are ubiquitous in the environment due to evaporation and incomplete combustion of fuels, use of consumer and personal care products, etc. and they can accumulate in foods. Some VOCs in foods can also be formed during food processing and preparation and migrate from food packaging. In this pilot study, a GC-MS method based on headspace solid-phase microextraction (SPME) was validated and used to analyse selected individual foods which can be consumed directly and 153 different total diet composite food samples for 13 VOCs. Vinyl chloride was not detected in any of the 153 composite food samples, while the other 12 VOCs were detected at various frequencies, with m-xylene being the most frequently detected (in 151 of the 153 samples), followed by toluene (145), 1,3,5-trimethylbenzene (140), ethylbenzene (139), styrene (133), 1,2,4-trimethylbenzene (122), benzene (96), p-dichlorobenzene (95), n-butylbenzene (55), chloroform (45), naphthalene (45) and trichloroethylene (31). Concentrations of the 12 VOCs in most of the food composite samples were low, with the 90th percentiles from 1.6 ng g(-1) for n-butylbenzene to 20 ng g(-1) for toluene. However, some VOCs were detected at higher levels with maxima, for example, of 948 ng g(-1) for m-xylene and 320 ng g(-1) for ethylbenzene in chewing gum, 207 ng g(-1) for styrene and 157 ng g(-1) for toluene in herbs and spices. VOCs were detected at higher levels in most of the individual food items than their corresponding composite samples, for example, the average chloroform concentration in the individual canned soft drinks was 20 ng g(-1) compared with 3.0 ng g(-1) in their composite, and the average toluene concentration in the individual canned citrus juice was 96 ng g(-1) compared with 0.68 ng g(-1) in their composite. Thus, for determination of VOCs in foods which can be consumed directly, their individual food items should be analysed whenever possible for accurate exposure assessment.

Levels and temporal trend of bisphenol A in composite food samples from Canadian Total Diet Study 2008-2012

Food composite samples from the Canadian Total Diet Study which was conducted each year from 2008 to 2012 rotating between different cities were analysed for bisphenol A (BPA). The overall levels of BPA in the composite food samples from each of the five years from 2008 to 2012 were similar in general with averages (range) of 7.7 ng/g (0.20-106 ng/g), 7.8 ng/g (0.26-110 ng/g), 6.9 ng/g (0.20-84 ng/g), 7.7 ng/g (0.20-105 ng/g) and 9.0 ng/g (0.15-90 ng/g) for 2008, 2009, 2010, 2011 and 2012, respectively. Levels of BPA in most of the non-canned food composite samples were low and no particular trends were observed. In contrast, the trend of BPA levels in canned food composite samples over the five years (2008-2012) varies. BPA levels in most of the canned food composite samples from 2008 to 2012 were consistent in general (e.g. canned luncheon meat: 10-18 ng/g, canned baked beans: 18-25 ng/g). While BPA levels over the five years were found to decrease for some canned food composite samples (e.g., canned fish: 109 ng/g in 2009 vs. 51 ng/g in 2012), they were also found to increase for some other canned food composite samples (e.g. canned meat soups: 90-104 ng/g in 2011-2012 vs. 29 ng/g in 2008). Thus, recent changes in can coating for food packaging to BPA-free alternatives may have not been fully reflected in all canned food products over the period from 2008 to 2012. Continued monitoring is necessary to more fully assess the potential impact on dietary exposure by the use of BPA alternatives in food contact materials.

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.