Comparison of N-nitrosamine formation mechanisms in vacuum and modified atmosphere packaged sausages using mathematical modelling

Abstract

This study investigated the comparative effects of vacuum and modified atmosphere packaging (MAP; 70% CO2 + 30% N2) on the formation dynamics of seven volatile N-nitrosamines (N-nitrosodimethylamine (NDMA), N-nitrosomethylethylamine (NMEA), N-nitrosodiethylamine (NDEA), N-nitrosodipropylamine (NDPA), N-nitrosopyrrolidine (NPYR), N-nitrosopiperidine (NPIP), and N-nitrosodibutylamine (NDBA)) in sausages during 12 weeks of refrigerated storage (4 °C). Weekly Gas Chromatography-Mass Spectrometry (GC-MS) analysis combined with two-way variance analysis (ANOVA) revealed that storage duration significantly increased all target nitrosamine concentrations (p <.005). Beyond standard statistical evaluation, a kinetic modelling approach was employed to elucidate the distinct reaction mechanisms driven by packaging atmospheres. The results demonstrated that the packaging type fundamentally dictated the formation kinetics. Notably, NDMA followed an “Acidity Controlled Delayed Growth” model under MAP, exhibiting a critical lag phase of 2.1 weeks (tlag) before accumulation commenced, whereas it remained below detection limits in vacuum packages. Furthermore, NPYR exhibited “Exponential Acceleration” kinetics in MAP, contrasting with the “Rapid Equilibrium” behaviour observed for NDBA and NDEA under vacuum conditions. These models achieved high determination coefficients (R2 > 0.90), mathematically demonstrating that packaging atmospheres shift underlying reaction pathways—from rapid saturation in vacuum to acid-catalyzed exponential growth in MAP. These findings underscore the necessity of evaluating nitrosamine dynamics within specific packaging contexts to ensure the chemical safety of processed meat products.