Fumonisins in grain-based foods, soy products and teas - April 1, 2012 to March 31, 2018

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.

Fusarium moniliforme and Fusarium proliferatum are plant pathogens common in grain-growing regions throughout the world. These pathogens can infect grain crops either in the field (pre-harvest) or during storage (post-harvest). The pathogens proliferate if grains are grown in hot, dry weather followed by very humid conditions and/or by storage under wet conditions. The plant pathogens produce mycotoxins known as fumonisins. These toxins are associated mainly with corn production; in countries where corn is a staple food, negative health effects have been observed including esophageal cancer in South Africa and China^{Footnote 1},^{Footnote 2}, and neural tube defects in Central America and the southwestern US^{Footnote 3}.

Grain-based foods, soy products and tea are also susceptible to contamination by fumonisins, specifically fumonisin B1 (FB1) and fumonisin B2 (FB2). These products are consumed in varying degrees by some or all populations in Canada.

In consideration of the factors mentioned above and their relevance to Canadians, grain-based foods (including but not limited to flour/flakes/meal/grains to crackers and pasta), soy products, and tea were selected for this multi-year targeted survey. The purpose of targeted surveys is to gather baseline information of the occurrence and levels of chemical hazards in food.

Over the course of these surveys from 2012 to 2017, a total of 4261 samples were collected and tested for FB1 and FB2. One or both forms were detected in 1076 (25%) samples tested. There are currently no Canadian limits for fumonisins in foods and all results associated with these products are reviewed by Health Canada's Bureau of Chemical Safety to determine if the levels observed are harmful to consumers. Levels detected in samples included in these surveys did not pose a health risk to Canadian consumers and there were no product recalls resulting from this survey.

CFIA will continue to monitor fumonisin levels as part of the multi-mycotoxin surveys in a variety of foods to ensure the safety of the Canadian food supply.

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

Fusarium moniliforme and Fusarium proliferatum are 2 types of fungi (also known as moulds) that can contaminate grains and other crops in the field (pre-harvest) and/or in storage (post-harvest). These fungi proliferate if crops are grown in hot, dry weather followed by very humid conditions. Mould growth is also favoured by storage under wet conditions. These moulds can contaminate grain-based foods, soy products and tea. These food products are consumed to varying degrees by some or all populations in Canada.

Moulds release mycotoxins, specifically fumonisins. Corn is the grain most vulnerable to contamination^{Footnote 4}. The levels of fumonisins can be elevated, even in the absence of visible signs of mould proliferation^{Footnote 1}. There are several forms of fumonisin: fumonisins B1 (FB1) and fumonisin B2 (FB2) are the most prevalent. While studies have focused on FB1, the available data suggests that FB2 has a similar toxicological profile^{Footnote 3},^{Footnote 5},^{Footnote 6},^{Footnote 7}. These contaminants are heat-stable up to 150°C and are unaffected by mechanical forces (such as grinding), but can be reduced by alkaline treatment^{Footnote 8}.

Although fumonisin contamination is mainly observed in corn, some scientific studies have shown that red wine^{Footnote 9}, sorghum^{Footnote 5}, white beans, wheat^{Footnote 5}, barley^{Footnote 5}, soybeans^{Footnote 5}, figs^{Footnote 5}, rice^{Footnote 10}, black tea^{Footnote 5}, and medicinal herbs^{Footnote 5} can be affected as well.

The ingestion of foods containing fumonisin may be harmful to human health. Health effects have been observed in specific populations where corn is a major component of the diet and where the climate favors mould proliferation. These effects include esophageal cancer (South Africa and China)^{Footnote 1},^{Footnote 2} and neural tube defects (Central America and the southwestern US)^{Footnote 3}. The precise biological effects are complex and relate to interference with cell metabolism4. Experimental animal studies have revealed that fumonisins induce liver and kidney damage in many species^{Footnote 11}. FB1 has been classified by IARC as possibly carcinogenic to humans based on evidence in experimental animal studies^{Footnote 2}. This study included FB1 and FB2.

The main objectives of this targeted survey were to generate additional baseline surveillance data on the levels of fumonisins in foods not routinely monitored under other CFIA programs, to assess compliance with proposed Canadian regulations, and to compare the prevalence of FB in foods in this survey with that of previous targeted surveys.

What did we sample

A variety of domestic and imported grain-based products, milled grains, soy products and tea were sampled between April 1, 2012 and March 31, 2018. Samples of products were collected from local/regional retail locations located in 6 major cities across Canada. These cities encompassed 4 Canadian geographical areas:

• Atlantic (Halifax)
•  Quebec (Montreal)
•  Ontario (Toronto, Ottawa)
• West (Vancouver, and Calgary)

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 the food on the open market were not considered in this survey. The samples originated in at least 40 countries.

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. In this report, the FB level refers to the sum of FB1 and FB2 levels.

There are no Canadian regulatory limits for fumonisins in foods. In the absence of established tolerances or standards, elevated levels in specific foods may be assessed by Health Canada on a case-by-case basis using the most current scientific data available.

What were the survey results

Of the 4261 samples that were tested, 75% were free from contamination by fumonisins. Of the 25% of samples where fumonisins was detected, there were various ranges of contamination as seen in Table 2. Average levels were highest in grain-based foods, and lowest in soy products.

There are 16 different grains associated with the grain-based foods; 5 of the grains were not associated with detectable fumonisin levels (arrowroot, kamut, rye, triticale and mixed grains). The detection rates of the remaining 11 types of grains range from 0.7% detection (millet, quinoa) to 61% (corn). See Table 3 below for a more detailed breakdown of the detection rates and fumonisin levels by grain type.

The 185 soy-based products tested included 26 tofu samples, 24 soybean samples, 16 soy-based infant formula samples, 13 soy flours, 9 meat alternatives, 9 soy beverages, 4 samples of tempeh, 3 soy-based infant cereals, 3 soybean paste samples, 2 samples of miso, 1 sample of soy protein, and 1 sample of soy nuts. Only 2 samples of tofu contained detectable levels of fumonisins.

The tea samples included both 377 samples of dried teas and 49 samples of ready-to-drink tea beverages. The dried teas included 101 green teas, 100 black teas, 100 herbal teas, 26 other teas (containing rice or other grains), 25 oolong teas and 25 white teas. Only one sample of black tea contained detectable levels of fumonisins (43 ppb).

Of the 4261 samples tested, 2939 samples were conventionally grown and 1322 samples were labelled as "organic". The detection rate was 28% for conventionally grown products and 18% in organic products. For conventionally grown products, the levels ranged from 20 ppb to 7710 ppb, with an average concentration of 382 ppb. For organic products, the levels ranged from 21 ppb to 7790 ppb, with an average concentration of 303 ppb. For a detailed breakdown of the results, see Appendix A, Tables A-1A-2 and A-3. As mentioned earlier, fumonisins are naturally occurring – expected to be seen in both conventionally grown or organic products. As samples were collected at retail, no information on is available conditions in the field and/or during storage of the raw commodities or whether the samples were treated with fungicides (may reduce mold formation and release of mycotoxins).

The results for the entire dataset, were forwarded to Health Canada's for a safety assessment. Health Canada is of the opinion that the levels of fumonisins in the products analyzed in this survey were unlikely to pose a health risk. No product recalls were warranted given the lack of a risk to human health.

What do the survey results mean

In this survey, 75% of samples of selected foods analyzed were free of detectable levels of fumonisins. Tables 4 through 16 present a comparison of the maximum, minimum and average fumonisin levels in specific food grains/food types observed in this study, which were comparable to previous targeted surveys^{Footnote 12},^{Footnote 13} and scientific literature^{Footnote 14},^{Footnote 15},^{Footnote 16},^{Footnote 17},^{Footnote 18},^{Footnote 19},^{Footnote 20},^{Footnote 21},^{Footnote 22},^{Footnote 23},^{Footnote 24},^{Footnote 25}.

* For a more detailed breakdown of corn products, see Appendix B

Appendix A

Appendix B