1. Where Nitrates Come From

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     Nitrates occur naturally in the environment and are produced by living organisms. It aids in the growth of fruits and vegetables. Nitrates are also added to some foods to help preserve them and maintain color. They are also found in water, although in varying amounts. Certain vegetables contain different amounts of nitrates, especially green leafy ones. The amount present is determined by many factors, like the environment the plant is grown in, how it is stored and how it is processed. All of these things affect the metabolic processes of the plant.

   Effects of Nitrates

   • Although nitrates help plants to grow, there are some negative effects when ingested by humans. It is not the nitrates that cause damage; your body metabolizes and converts them into nitrites. In adults, the conversion takes place in the saliva. In infants, it takes place in the gastrointestinal tract. Nitrites have been linked to cancer and other health complications. Most adults are not affected by the amounts of nitrates that are in the food we eat. The Expert Committee on Food Additives has assigned a system of values to determine the safety of certain foods. It is deemed safe to have an intake of up to 5 mg of sodium nitrate per kg of body weight or up to 3.7 mg of nitrate ion per kg of body weight.

Three children have died and 35 people have become ill from drinking nitrite-tainted milk in China's north-western Gansu province, Xinhua news agency has reported in the latest food safety scandal to hit the dairy industry.

Most of the 35 were children under 14 now being treated at two hospitals in Pingliang city, Xinhua said, citing the local government and health bureau.