Explainer: How does lead get in food?

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The news scare about excessive lead levels in noodles will one day pass, whether that takes a week or a month. Products that have been banned may sooner or later be allowed back on the shelves if they pass inspection. However, what we the consumers need to understand is how lead can get into food, and what can or cannot be done about it.

According to a World Health Organisation, there is no known level of lead exposure that is considered safe, and exposure to lead is estimated to account for 1,43,000 deaths a year, with the highest burden in developing regions. As we explain below, it is not possible to completely eliminate lead from food, so government authorities instead set limits on how much lead is acceptable.

The amount of lead that is allowed in food varies from one food item to the other. For example, according to regulations set in 2011 by Food Safety and Standards Authority of India (FSSAI), fruit and vegetable juices are allowed to contain up to 1 part per million (ppm) by weight in lead (1 ppm means that in a thousand kilograms of food, up to one gram be lead), whereas dry tea may have up to 10 ppm. Sugar is allowed to contain 5 ppm but hard-boiled sugar sweets may only have up to 2 ppm.

Government food regulators allow for some amount of lead in food because it is part of the environment. Some of it is present naturally, but human activity has also added lead to the environment. One of the largest contributors around the world was petrol fuel containing lead. In 2000 India mandated that all petrol fuel be lead free, and in 2011 the UN declared India to be a lead-free petrol country. However, some of that lead that was emitted into the air could still linger in the soil. Other sources include industrial processes, the manufacture of lead-acid based car batteries, and house paint.

How does lead get into food?

One way, according to the US government’s Food and Drug Administration (FDA), is through the soil. “Lead in soil can be deposited on or absorbed by plants, including plants grown for food. Lead that gets in or on the plant cannot always be completely removed by washing or other steps in the processing of the food.”

Lead can also get into food during processing. For example, if any of the water pipes or the paint in the factory contains lead, that could get into the food. Contamination during processing could raise lead levels above government established limits. If that is the case, then the food manufacturers can and need to take steps to prevent it from happening.

Uday Annapure, an associate professor in the department of Food Engineering and Technology at the Institute of Chemical Technology in Mumbai, told The Wall Street Journal that one possible source of contamination was the water used to manufacture the noodles. He added that some components of the soup-flavoring packet, such as onion powder and wheat flour, “come from agricultural sources, all vulnerable to lead contamination.”

Another possible contaminant could be the packaging itself, and not the edible content inside. The US government once asked candy manufacturers in Mexico to halt shipments because it found that the paper and ink on the wrapper contained harmful amounts of lead.

What harm does lead do?

Y K Amdekar, medical director, Wadia Hospital, told DNA, “Lead intervenes with a variety of body processes. It also interferes with the development of the nervous system and is therefore particularly toxic to children. Ingesting it on regular basis and for a longer period of time can also cause permanent learning and behaviour disorders. Large amount of lead ingestion can cause symptoms include stomach pain, confusion, headache, mental retardation, anaemia, irritability, and in severe cases seizures. If the problems aggravate, some time children need surgery.”

Other sources of lead

House paint is a big source of lead paint contamination, not just in food but directly in the home. India has not yet banned lead from paints. Although some of the big brands say that their paints are lead-free, a large number still have very high levels of lead, according to a June 2015 report by Toxics Link, an environmental NGO. Toxics Link states that in 2013 the Bureau of Indian Standards (BIS) lowered the permissible amount of lead in paints from 1000 ppm to 90 ppm. This limit is the same as in the US and other countries. However, the BIS’s standards are entirely voluntary. So, for example, 32 of 101 paints that were tested had lead levels of 10,000 ppm or more, but they are sold legally.

How can you protect your children and yourself?

One way may be to have a varied diet and not serve the same food too frequently. Nitin Shah, paediatrician at PD Hinduja Hospital told DNA, “We advise parents not to give instant food like Maggi to their children on a daily basis. It can be a snack item but can’t replace the main meal.”

Another step parents can take is to watch out for lead exposure in the house. If you are about to paint your wall or if you buy wooden toys, check whether the paint is lead free. Parents who are concerned about the existing paint can start by getting their children’s blood tested for lead levels. Speak to a paediatrician about this. There are lead test kits for home use available in other countries, but so far they do not seem to be for sale in India.

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