Nitrite accumulation in preserved and leftover vegetables: The role of storage conditions in food safety

Nitrite accumulation in processed and leftover vegetables has raised public health concerns due to its potential toxicity and role in forming carcinogenic compounds. This study assessed nitrite content in two nitrate-rich vegetables: cabbage and white radish, following cooking or salt preservation and storage at 4 °C, 21 °C, 37 °C, and 60 °C. Initial processing did not increase nitrite levels, but storage conditions had a significant impact. Nitrite remained undetectable at 4 °C and 60 °C, while samples stored at 21 °C and 37 °C exhibited rapid increases. Cooked vegetables at 21 °C, nitrite peaked after 24 h at 84.3 ± 8.28 mg/kg in cabbage and 94.64 ± 6.31 mg/kg in white radish. At 37 °C, nitrite occurred earlier (8 h), reaching 110.6 ± 8.21 mg/kg in cabbage and 96.53±5.34 mg/kg in radish within 12 h. Salt-preserved samples followed a similar trend but with lower peak levels, 36.29±4.27 mg/kg in cabbage and 20.32±0.21 mg/kg in radish at day 2 of storage. These findings emphasize the importance of storage temperature in controlling microbial driven nitrite formation. Maintaining vegetables below 4 °C or ≥60 °C can effectively limit nitrite accumulation. This study offers valuable guidance for safe food storage, supports evidence-based public health recommendations, and contributes to efforts to reduce food waste through informed leftover consumption.