Under the microscope: World Metrology Day - A safe food system using the science of metrology

A blog post by Kelly LeBlanc and Patricia Grinberg, Research Officers at the National Research Council of Canada’s Metrology Research Centre

When we talk about food safety, we often think about various undesirable contaminants, such as pesticides and toxic heavy metals, and the desire to keep levels of these contaminants in our foods as low as possible.

Governments or intergovernmental agencies often set target guidelines for maximum allowable limits of specific contaminants in different types of foods. This means that food producers need to regularly test their products before releasing them to market to ensure these guidelines are met. However, as we learn more about the risks associated with the intake of certain contaminants, these allowable limits become lower and lower, making it increasingly difficult to measure these contaminants in food products.

Some of the tools used to help testing laboratories demonstrate the reliability of their measurements are Certified Reference Materials (CRMs). CRMs are used as control samples because they mimic the samples being analyzed and the concentrations of the components of interest have been established with a high degree of confidence. Therefore, testing labs will measure CRMs alongside their samples – when the results for the CRMs match those provided on their associated documentation (known as their “Certificate of Analysis”), the lab can be confident that their analysis method is performing properly and provide accurate results for their samples. Some of the ways NRC CRMs can be used to ensure a safe global food system are highlighted below.

As we become more aware of the negative environmental impacts of conventional livestock production, larger proportions of the population are choosing to substitute their meat intake with alternative sources of protein. Along with more traditional high-protein foods, such as beans and lentils, Western cultures are also beginning to turn towards insects as a food source. We know that farming insects has significantly reduced environmental impacts compared to conventional farming (beef production requires 22,000 times more water and emits 20 times more greenhouse gasses than cricket farming). However, we are still learning about the uptake and metabolism of toxic metals in insects, so testing these products is extremely important.

The NRC has prepared three new CRMs of high-protein foods from insects: BFLY-1 (black soldier fly larvae powder), KRIK-1 (cricket powder), and VORM-1 (mealworm powder). Along with their crude protein, fibre and carbohydrate contents, the Certificates of Analysis for these materials contain data relating to their contents of several elements of potential concern, including lead, arsenic and cadmium, as well as a number of other essential elements, such as selenium and zinc. As a new type of food product which has a higher protein content than conventional meat, the accurate analysis of metals in insect materials can be complicated and these CRMs will provide a useful tool to food producers as this industry continues to grow.

Over the past few years, concern about the arsenic content of rice, particularly in baby food, has risen significantly. This has caused regulators to lower the allowable limits in these products and to base these limits on the chemical forms of arsenic which are the most toxic (inorganic arsenic). When also considering factors such at the United States Food and Drug Administration’s new “Closer to Zero” initiative, which aims to keep levels of unavoidable contaminants as low as possible in foods intended for babies and young children, robust analysis methods are required to keep pace with policy. The NRC CRM BARI-1 (baby cereal coarse rice flour) has an inorganic arsenic content right which matches Health Canada’s current regulatory limit, making it an ideal material for quality control during analysis. Additionally, the Certificate of Analysis for BARI-1 contains values for all of the “toxic four” elements of interest in food analysis: arsenic, cadmium, lead and mercury.

The Inorganic Chemical Metrology team has a number of other food CRMs, one of them being SPIN-1 (spinach powder) certified for its nitrate concentration. The benefits and risks of the consumption of large amounts of nitrates are widely debated due to the potential for increasing both cardiovascular health and the risk of gastrointestinal cancers. Depending on the employed agricultural practices, spinach can be very high in nitrate; these concentrations significantly increase upon drying to produce the spinach powders frequently used as nutritional supplements.

Learn more about CRMs here: Certified reference materials

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