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

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.