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Food Safety Focus (192nd Issue, July 2022) – Article 4

Proper Storage – Key to Minimising Nitrite Level Increase in Cooked Vegetables

Vegetables are an important part of a healthy diet. However, some people prefer not to take cooked vegetables left out overnight to work for lunch because of the concern that they might contain high levels of nitrite which could be bad for health. To this end, the Centre for Food Safety conducted a risk assessment study on the nitrite levels in cooked vegetables.

The study found no nitrite in any of the vegetable samples before or shortly after cooking. When stored at refrigerated temperature (0 to 4°C ) overnight, nitrite was not detected in all cooked vegetable samples. However, when stored at room temperature, the nitrite levels started to increase in some samples after storing for 12 hours. The study results revealed that storage temperature has a significant role in the nitrite levels in cooked vegetables.

Members of the public are advised to store cooked vegetables properly to delay nitrite formation. Leftovers should be refrigerated within two hours after cooking and consumed as soon as possible. Home-packed meals or lunchboxes should be stored in a fridge immediately once arriving at the workplace. Reheat food thoroughly until its core temperature reaches 75°C before consumption. A diverse diet including a variety of vegetables is essential for better health.