Metals such as arsenic, cadmium, lead and mercury are natural occurring chemical compounds. They can be present at various levels in the environment, e.g. soil, water and atmosphere. Metals can also occur as residues in food because of their presence in the environment, as a result of human activities such as farming, industry or car exhausts or from contamination during food processing and storage. People can be exposed to these metals from the environment or by ingesting contaminated food or water. Their accumulation in the body can lead to harmful effects over time.

 FSSAI Safety Limits for Heavy MetalsTo protect consumers, regulatory bodies across the world have established regulations with stringent limits on the permitted levels of heavy metals in different items of food. The Food Safety and Standards Authority of India (FSSAI), the apex regulatory body on food in India, has recommended safety limits for metal contaminants in F&B, which should not be exceeded. For example, there is a specified upper limit for lead in beverages such as soft drinks, juices and tea; and food items like ice creams, canned fish & meat, sugar, edible oils, etc.

Similarly, the limits for other metal contaminants have also been specified for F&B.

In the light of the recent lead contamination controversy, the FSSAI has issued a new notification that has fixed, among other parameters, the maximum limits for the metals Lead, Copper, Arsenic, Mercury, Tin, Cadmium & Zinc in food items like Noodles, Pastas & Macaroni and other such food items, which had previously been classified by FSSAI under ‘Foods Not Specified’.

How Are Metals Tested in F&B?

The presence of heavy metal contaminants in F&B makes it important for the food industry to ensure that their products are free from these toxic elements by regularly testing their ingredients and products for compliance with the regulatory requirements.

Testing for metals in foodstuff essentially involves following four steps:

• Sampling: The objective of this step is to obtain a small and representative portion from the large sample in such a way that any subsequent test on the sample will give reproducible results.

• Destruction of organic matter: Th e commonly used methods of destruction of organic matter can be broadly grouped into wet oxidation, dry ashing and microwave digestion.

• Separation and concentration of the metal: Once the organic component is destroyed, the element of interest may be concentrated by applying physico-chemical methods.

• Measurement and determination of the metal: The concentrated element is then subjected to analytical methods to determine its actual level in the original sample of food.

The FSSAI has recommended a number of methods for testing metal contamination in foodstuff , which have been approved and validated internationally by leading agencies like the USFDA and the European Food Safety Authority (EFSA) of the EU.

It is important to note that approval by international agencies in various countries means that the methods have been standardised and harmonised as per global standards. Therefore, when Indian food products are exported to these countries and retested before distribution, they will pass the quality and safety checks easily.

Some of the approved methods include Atomic Absorption Spectrometry (AAS) for testing lead, cadmium, copper and zinc. Besides mercury and arsenic, the other four metals can also
be estimated by colorimetric methods. The most advanced method for testing metals, which is considered the “Gold Standard” is a combination of Microwave Digestion for sample preparation, followed by Inductively Coupled Plasma Mass Spectrometry (ICP MS) for sample analysis. ICP MS gives the advantage of analyzing
all the metals at the same time with minimum manual intervention.