Interactive Effects of Temperature and Packaging on NDMA, DMA, and TMAO in Roasted Alaska Pollock Fillets and Pathway...

To elucidate the synergistic effects of storage temperature and packaging on N-nitrosodimethylamine (NDMA) and its precursors dimethylamine (DMA) and trimethylamine N-oxide (TMAO) in roasted Alaska pollock fillets, two storage experiments were conducted. In Experiment I, commercially packaged fillets were stored at -20, 4, 10, 20, and 30 °C for 310 d. A two-way factorial ANOVA revealed a significant temperature × time interaction (F(24, 70) = 39.386, p < 0.001, partial η² = 0.931). NDMA formation was delayed until day 172 at -20 °C; however, the 4, 10, and 20 °C groups exceeded the 4 μg/kg limit by day 263, with the 20 °C group peaking at day 263 (4.26 μg/kg) before declining to 3.73 μg/kg by day 310. In Experiment II, a three-way factorial ANOVA was applied to samples stored under oxygen-absorber or vacuum packaging at refrigerated (4 °C) or ambient (22 °C) temperature for 270 days. The temperature × packaging × time interaction was significant for NDMA, DMA, and TMAO (p < 0.001). The partial η² for NDMA (0.933) was markedly larger than for DMA (0.540) and TMAO (0.607), indicating stronger combined effects on NDMA. The main effect of temperature on DMA was dominant (partial η² = 0.994), whereas NDMA formation depended strongly on both temperature and packaging. During the 270-day storage, all refrigerated groups remained below the 4 μg/kg limit throughout; however, the ambient vacuum-packaged (BCZ) group transiently exceeded the limit (reaching 4.21 μg/kg on day 60) and subsequently fluctuated near the limit. These findings provide a scientific basis for designing safer storage and packaging strategies for such dried aquatic products.