Introduction
The definition of radiation in science refers to the energy carried by waves or particles. In common conversations, radiation refers to the harmful ionising radiation, which are particles with enough energy to break chemical bonds, cause mutations to DNA and increase your risk of cancer.
Radioactive materials are high energy, unstable materials that spontaneously decay to more stable forms with emission of radiation. Humans are constantly exposed to radiation from outer space (cosmic radiation), the environment, medical imaging scans, and food. For example, in the environment, radon – a radioactive gas – is naturally found in the air we inhale. Some gemstones, such as zircon, are also naturally radioactive. Other radioactive elements such as uranium, thorium, and actinium are naturally present in the Earth’s minerals.
This article provides more information on the occurrence and safety of radioactive materials found in food.
What is natural radiation in food?
Did you know we are exposed to natural radiation in food all the time? All food naturally contains radioactive materials. Potassium – an essential nutrient for health – has a small percentage in the radioactive form (potassium-40). Radium – another radioactive element – is also commonly found in food containing potassium. Hence, all food, particularly food high in potassium like bananas, carrots, potatoes, leafy vegetables, salt, peanuts and red meat, are "radioactive".
Although radiation can damage our DNA, our bodies can repair the damage. The natural radiation from our food and environment, together with the cosmic radiation from outer space is well within the levels that the human body can tolerate. Chart 1 illustrates the levels of radiation that a typical human is exposed to.
As part of SFA's food safety monitoring regime, SFA's National Centre for Food Science (NCFS) regularly monitors the background radioactivity levels for common food items such as eggs, vegetables, milk and fish. The radiation levels in the surveyed food were found to be consistent with naturally occurring levels.
Chart 1 – A comparison of radiation doses from various sources (pictures from freepik.com)
Artificial radiation in food – Is it a food safety concern?
Artificial radiation in food is largely due to fallout from nuclear power plant accidents. During such events, large amounts of artificial radioactive materials are released into the atmosphere as gas and dust. Notable nuclear accidents include the Three Mile Island (USA) accident in 1979, Chernobyl (Ukraine) disaster in 1986 and Fukushima (Japan) accident in 2011. These artificial radioactive materials are deposited on vegetation, soil and water, which are then taken in by the plants and animals that we eat. Compared to its natural occurrence, these radioactive materials released from nuclear power plants are significantly enriched and therefore, can lead to serious health problems.
What is SFA doing to ensure food from nuclear-affected areas/countries is safe for consumption?
SFA's food safety monitoring programme is guided by a science-based risk assessment and management approach that is consistent with international standards. Under this programme, SFA has a system in place to ensure that both imported and locally produced food is safe for consumption. In the event of a nuclear fallout in a source exporting food to Singapore, SFA will assess the situation before taking the necessary action such as suspension of imports. These food imports are also subjected to SFA’s inspection and testing. Food products that do not meet our food safety requirements will not be allowed for sale.
Today, most of the radiation from these artificial radioactive materials have reduced over time due to the natural decay process. Through close monitoring and surveillance, SFA will ease restrictions or lift the suspension of food imports from affected areas/countries when they comply with our food safety requirements. Therefore, while food from affected areas/countries can still be expected to contain some levels of artificial radiation, these would be well within safe levels.