Food chemistry – Targeted surveys – Final report
Summary
Targeted surveys provide information on potential food hazards and enhance the Canadian Food Inspection Agency's (CFIA's) routine monitoring programs. These surveys provide evidence regarding the safety of the food supply, identify potential emerging hazards, and contribute new information and data to food categories where it may be limited or non-existent. They are often used by the agency to focus surveillance on potential areas of higher risk. Surveys can also help to identify trends and provide information about how industry complies with Canadian regulations.
Chemical hazards in foods can come from a variety of sources. Metals are naturally-occurring elements that may be present in very low amounts in rock, water, soil, or air. Finding these substances in food products is not unexpected as trace levels generally reflect normal accumulation from the environment. They may be present in finished foods due to their presence in the ingredients used to manufacture those foods, and/or may be unintentionally incorporated along the food production chain. Metals of highest concern to human health include arsenic, cadmium, lead, and mercury and these have been shown to have effects on human health following long term exposureFootnote 1.
The main objectives of this targeted survey were to generate additional baseline surveillance data on the level of metals in foods not routinely monitored under other CFIA programs, and to compare, the detection rate of metals in foods in this survey with that of previous targeted surveys.
A total of 422 samples of exotic meats, seafood and sugar/molasses were collected from retail locations in 11 cities across Canada and tested for metals/elements. Only the results of the metals of highest concern (arsenic, cadmium, lead, and mercury) are presented in this report. Lead and arsenic had the lowest and the highest detection rate, respectively. Most (85%) of the survey samples contained one or more metals, while 24% of the samples contained traces of all four toxic metals. The highest levels of these metals were found in seafood samples. Detectable levels of at least one metal were found in 99.6% of seafood products. The detection rates and the levels of metals reported in this targeted survey were comparable to those previously found in similar product types.
The levels of mercury detected in all fish samples met the existing tolerances of 0.5 parts per million (ppm) or 1.0 ppm, depending on the fish type (100% compliant). There are no regulations in Canada for metal levels in the other products tested. Health Canada determined that none of the samples analyzed for metals in this survey posed a concern to human health.
What are targeted surveys
Targeted surveys are used by the CFIA to focus its surveillance activities on areas of highest health risk. The information gained from these surveys provides support for the allocation and prioritization of the agency's activities to areas of greater concern. Originally started as a project under the Food Safety Action Plan (FSAP), targeted surveys have been embedded in our regular surveillance activities since 2013. Targeted surveys are a valuable tool for generating information on certain hazards in foods, identifying and characterizing new and emerging hazards, informing trend analysis, prompting and refining health risk assessments, highlighting potential contamination issues, as well as assessing and promoting compliance with Canadian regulations.
Food safety is a shared responsibility. We work with federal, provincial, territorial and municipal governments and provide regulatory oversight of the food industry to promote safe handling of foods throughout the food production chain. The food industry and retail sectors in Canada are responsible for the food they produce and sell, while individual consumers are responsible for the safe handling of the food they have in their possession.
Why did we conduct this survey
Chemical hazards in foods can come from a variety of sources. Metals are naturally-occurring elements that may be present in very low amounts in rock, water, soil, or air. Finding these substances in food products is not unexpected as trace levels generally reflect normal accumulation from the environment. They may be present in finished foods due to their presence in the ingredients used to manufacture those foods, and/or may be unintentionally incorporated along the food production chain.
Metals of highest concern to human health include arsenic, cadmium, lead, and mercury and these have been shown to have effects on human health following long term exposure. The human health effects depend on the metal, its concentration in the food, and other possible exposure effects/sourcesFootnote 1. Manufacturers are responsible for measures aimed at reducing accidental introduction of these elements in foods.
The main objectives of this targeted survey were to generate additional baseline surveillance data on the level of metal levels in foods not routinely monitored under other CFIA programs, and to compare the detection rate of metals in foods in this survey with that of previous targeted surveys. Only the results of the metals of highest concern (arsenic, cadmium, lead, and mercury) are presented in this report.
What did we sample
A variety of domestic and imported exotic meats (bison, frog, snail, etc.), seafood (fish, shellfish and crustaceans) and sugar/molasses were sampled between April 1, 2021 and March 31, 2022. Samples of products were collected from local/regional retail locations located in 11 major cities across Canada. These cities encompassed 4 Canadian geographical areas:
- Atlantic (Halifax and Moncton)
- Quebec (Montreal and Quebec City)
- Ontario (Toronto and Ottawa)
- West (Calgary, Saskatoon, Vancouver, Victoria and Winnipeg)
The number of samples collected from these cities was in proportion to the relative population of the respective areas. The shelf life, storage conditions, and the cost of food on the open market were not considered in this survey.
| Product type | Number of domestic samples | Number of imported samples | Number of samples of unspecified Table Note a origin | Total number of samples |
|---|---|---|---|---|
| Exotic meats | 43 | 43 | 8 | 94 |
| Seafood | 60 | 215 | 8 | 283 |
| Sugar/Molasses | 11 | 20 | 14 | 45 |
| Total | 114 | 278 | 30 | 422 |
How were samples analyzed and assessed
Samples were analyzed by an ISO/IEC 17025 accredited food testing laboratory under contract with the Government of Canada. The results are based on the food products as sold and not necessarily as they would be consumed, whether the product sampled is considered an ingredient or requires preparation prior to consumption (for example, mixing with liquid or other ingredients).
Contaminants and other adulterating substances in foods have regulatory maximum levels. In 2014, Health Canada updated regulatory tolerances for arsenic and lead in a variety of ready-to-serve beverages, and infant formula when ready-to-serveFootnote 2. A maximum limit has also been established for mercury in commercial fish that are sold at the retail levelFootnote 3. in the absence of a specific maximum level, the levels of arsenic, cadmium, mercury and lead may be assessed by Health Canada on a case-by-case basis using the most current scientific data available.
What were the survey results
A total of 422 samples of exotic meat, seafood and sugar/molasses were analysed for arsenic, cadmium, lead and mercury. Most (85%) of the survey samples contained one or more metals, whereas 13% of the samples contained traces of all four metals. While 99.6% of seafood products contained traces of at least one metal, only 47% of sugar/molasses samples contained one or more metals and none of those had detectable levels of all four toxic metals. At least one of the toxic metals was detected in 61% of the exotic meat samples.
| Product type | Number of samples | % positive for arsenic | Average level (range) of arsenic (ppm) | % positive for cadmium | Average level (range) of cadmium (ppm) | % positive for lead | Average level (range) of lead (ppm) | % positive for mercury | Average level (range) of mercury (ppm) |
|---|---|---|---|---|---|---|---|---|---|
| Exotic meats | 94 | 45 | 0.0683 (<LOD-0.390) | 17 | 0.0757 (<LOD-0.268) | 19 | 0.0277 (<LOD-0.0567) | 33 | 0.0028 (<LOD-0.0062) |
| Seafood | 283 | 99.6 | 1.364 (<LOD-12.7) | 41 | 0.111 (<LOD-1.58) | 23 | 0.0864 (<LOD-0.530) | 96 | 0.0362 (<LOD-0.252) |
| Sugar/Molasses | 45 | 38 | 0.0252 (<LOD-0.110) | 2 | 0.010 (<LOD-0.010) | 18 | 0.0801 (<LOD-0.490) | 18 | 0.0029 (<LOD-0.0063) |
<LOD = Below the limit of detection (0.001 – 0.01 ppm, depending on the analyte)
Note: Average values were calculated using only results for samples with quantifiable metal levels
Arsenic
Arsenic had the highest overall detection rate; it was detected in 81% of samples. Seafood products had the highest (99.6%) percentage of samples with detectable levels of arsenic, followed by exotic meats (45%) and sugar/molasses (38%). Seafood products had a much wider range of arsenic levels than other product types with highest level at 12.7 ppm. Maximum levels were observed in samples of haddock, a bottom dwelling fish.
Cadmium
Cadmium was detected in 31% of samples tested in this targeted survey. Seafood products had the highest average cadmium level and higher maximum level than other product types. Although seafood is a commodity known to contain elevated levels of cadmiumFootnote 3, higher levels of cadmium (0.237 versus 0.196 ppm) were observed in canned seafood products, suggesting that migration of cadmium from the packaging material could contribute to the levels observed in the finished product.
Lead
Lead had the lowest overall detection rate; it was detected in 22% of samples tested. The detection rate was similar for all product types. Exotic meats had lower lead levels compared to other product types tested in this survey. The highest level of lead in this survey (0.530 ppm) was detected in a sample of frozen seafood mix.
Mercury
Mercury was detected in 73% of samples tested in this survey. While mercury was detected in 96% of seafood samples, other product types had lower detection rates and much lower detected levels of mercury. The highest levels of mercury were observed in samples of canned tuna.
What do the survey results mean
The detection rates and the levels of metals reported in this targeted survey were comparable to those previously found in these product typesFootnote 4, Footnote 5, Footnote 6, Footnote 7, Footnote 8. The differences observed may be due to the sample size and the specific type of product tested. Some increases in the detection rates between the surveys years were also associated with a more sensitive method used in the current year.
The levels of toxic metals in exotic meats observed in this surveys year were higher than levels reported for the CFIA's 2019 National Chemical Residue Monitoring Program (NCRMP) survey in these meat typesFootnote 4. This difference was associated with high levels of metals in products included exclusively in this survey, namely snail and frog products that included canned commodities. Other product types tested in both surveys had comparable levels of toxic metals.
As previously observed in the CFIA surveys, seafood products were more likely to contain detectable levels of toxic metals than other commodities. High levels of metals in seafood products are consistent with the fact that seafood can rapidly accumulate elevated concentrations of metals from the contaminated aquatic environmentFootnote 9. As expected, the highest levels of metals were present in mollusks (bivalves in particular) due to their a sedentary lifestyle and feed by filtering water which results in bioaccumulation of heavy metals. High levels of arsenic were also observed in bottom dwelling fish known to be exposed to greater quantities of arsenic due to their proximity to arsenic-contaminated sedimentsFootnote 10.
One of the objectives of this targeted survey was to generate additional baseline surveillance data on the level of mercury in sugar/molasses, as elevated levels of mercury were observed in this product type in previous years. It was confirmed that although in the 2011-2013 mercury survey, one granulated sugar sample had elevated levels of mercury, other results (<0.0073 ppm) closely matched those reported in this survey.
| Product type | Year (survey) | Number of samples | % positive for arsenic | Average level (maximum) of arsenic (ppm) | % positive for cadmium | Average level (maximum) of cadmium (ppm) | % positive for lead | Average level (maximum) of lead (ppm) | % positive for mercury | Average level (maximum) of mercury (ppm) |
|---|---|---|---|---|---|---|---|---|---|---|
| Exotic meats | 2021 | 94 | 45 | 0.0683 (0.390) | 17 | 0.0757 (0.268) | 19 | 0.0277 (0.0567) | 33 | 0.0028 (0.0062) |
| Exotic meats | 2019 (NCRMP) | 343 | 33 | 0.0113 (0.029) | 34 | 0.0594 (0.416) | 0.3 | 0.0050 (0.0050) | 39 | 0.0002 (0.0006) |
| Seafood | 2021 | 283 | 99.6 | 1.364 (12.7) | 41 | 0.111 (1.58) | 23 | 0.0864 (0.530) | 96 | 0.0362 (0.252) |
| Seafood | 2019 | 196 | 100 | 2.885 (30.7) | N/A | N/A | N/A | N/A | N/A | N/A |
| Seafood | 2016 | 997 | 99.7 | 1.461 (51.8) | 56 | 0.083 (2.52) | 32 | 0.0458 (1.47) | 96 | 0.0375 (3.48) |
| Sugar/Molasses | 2021 | 45 | 38 | 0.0252 (0.110) | 2 | 0.010 (0.010) | 18 | 0.0801 (0.490) | 18 | 0.0029 (0.0063) |
| Corn syrup/Molasses | 2013 | 21 | 48 | 0.0653 (0.111) | 5 | 0.057 (0.057) | 62 | 0.0277 (0.272) | 0 | ND |
| Sugar/Corn syrup/Molasses | 2011 to 2013 | 126 | N/A | N/A | N/A | N/A | N/A | N/A | 31 | 0.0026 (0.0423) |
Note: Average values were calculated using only results for samples with quantifiable metal levels
N/A: not available; not reported in this survey
ND: not detected above LOD
The levels of mercury detected in fish samples met the existing tolerances of 0.5 parts per million (ppm) or 1.0 ppm depending on the fish type. There are no regulations in Canada for metal levels in the other products tested. Health Canada determined that none of the samples analyzed for metals in this survey posed a concern to human health.