More people than ever are entering the conversation about food safety and are showing interest in the quality of food they are consuming. Urbanization and increased incomes, along with globalization, contributes to countless varieties of foods and increased consumption habits worldwide. Many factors can contribute to contaminants in our food through accumulation in soil and water resources. Mining and metallurgical processes can cause heavy metals to appear; the use of pesticides, fungicides and fertilizers in agricultural practices also leach into our food supply. Food preservatives, coloring agents, and emulsifiers can be used in manufacturing and packaging sectors, making our food items unsafe to consume. Whether it is agricultural products or processed foods it should be confirmed that they are safe to consumed.
Global organizations like World Health Organization (WHO), United States Food and Drug Administration (USFDA), European Commission (EC), China Food and Drug Administration (CFDA), and Food Safety and Standards Authority of India (FSSAI) are all dedicated to ensuring food safety. These agencies are continuously updating and implementing regulations to include current food safety requirements. They regulate food manufacturers and testing laboratories to reduce the risk of contaminations and improve the testing capabilities to ensure the food safety. In this blog post, we will discuss how heavy metals play a role in food safety and how sophisticated techniques like ICP-MS are used to ensure that are foods are safe from harmful metals.
Heavy Metals and Toxicities
Metals can be classified as lighter metals and heavy metals. Based on density, lighter metals are within the range of 0.5-3.7 g/cm3 whereas heavy metals have a density greater than 3.7g/ cm3. 100+ years of deposition of heavy metals into soil and water by industrial pollution leads to contaminants showing up on our plates via the food chain. Here are two examples of heavy metals that affected large populations:
In 1956, Minamata disease – caused by methyl mercury, an industrial waste deposited in water resources was discovered in Japan. Methyl mercury had bio accumulated in the shell fishes inhabiting local water resources from 1932 to 1968, resulting in the spread of the disease to humans via the food chain. Damage to hearing, vision, paralysis, coma and even death in severe cases were observed due to this disease.
In 1950, Itali-itai disease emerged from cadmium accumulation in rice by way of industrially polluted water supplied to paddy fields. The disease caused calcium loss in bones, renal failure, and severe muscle and bone pain.
These are only two examples. There are many other major evidences like Niigata disease, which convey the seriousness of heavy metal contamination and the effects of toxicities even at trace levels.
Role of ICP-MS in Ensuring Food Safety
We understand the importance of monitoring and quantifying heavy metals such as mercury, cadmium, arsenic, lead, chromium, nickel, etc. considering the high risk they pose to living beings even at trace levels. Continuous monitoring and quantification of these elements is necessary to prevent foodborne diseases.
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ICP-MS is an efficient analytical tool in the analysis of heavy metals in food sources. As an example, let’s take the challenging case of lead appearing in highly-consumed food and milk products:
European Commission regulation (EC) No 1881/2006 and Food Safety and Standards (Contaminants, Toxins) has determined the maximum level of lead in milk is 0.02mg/kg. Consider a milk sample containing 20µg/kg. If the milk sample is diluted to 10-fold after the digestion process, the sample solution will contain 2µg/kg. This requires us to plot a calibration curve with 2µg/kg. If the milk product contains high fat and/or salt, it may require more dilutions. If the dilution is increased to 50-fold, the solution will contain 0.4µg/kg. Then the linearity should contain 0.4µg/kg as one of the calibration point. But the methodology requires a quantification level which should be lower than the maximum limit with confidence level. So, there is a need of higher sensitivity at lower concentration levels, in this case minimum 0.2µg/kg. For food sample analysis; sensitivity, high dynamic range, repeatability in the presence of matrix interferences, reduced background noise with high robustness are very important elements. There are other techniques to quantify metals like atomic absorption and optical emission, but in the above scenario, all the requirements are fulfilled by ICP-MS. There are many food commodities which require a low-level detection at high accuracy with fast analysis, like the detection of cadmium in seafood and infant food, or chromium in refined sugar, etc. From a food safety perspective, we need to ensure that food commodities are safe to import and supply for consumption.
ICP-MS is capable of quantifying almost all elements of periodic table, at trace levels, in one go. The speed and accuracy of ICP-MS analysis helps the testing laboratories, scientists and chemists to qualify and/or quantify the contaminants with high accuracy, quality data and throughput. This automated technique not only quantifies the elements at trace levels, it also provides robust in-field research options. For example, the easy hyphenation of Thermo Scientific™ iCAP RQ ICP-MS to chromatographic systems like GC, LC and IC with single Qtegra™ Intelligent Scientific Data Solution (ISDS) Software makes the Speciation studies simple. Highly toxic inorganic arsenic can be quantified by this technique very accurately.
By providing high sensitivity, reliability, accuracy, ICP-MS helps to quantify toxic heavy metals to help ensure food safety. For more information, please refer to the additional resources below.
View this blog post: How to Improve Your ICP-MS Analysis, Part 1: Contamination by Dr. Simon Nelms
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