Controlling nitrosamine accumulation in dry fermented sausages using Lacticaseibacillus rhamnosus H7: The role of physicochemical drivers and precursor depletion

Lacticaseibacillus rhamnosus H7, selected for its superior nitrite degradation capacity (94.60%) in nitrite-supplemented MRS broth, was evaluated as a starter culture in dry fermented sausages at different inoculation levels. Inoculation significantly enhanced product safety, achieving up to 44.82% reduction in total nitrosamines. Simultaneously, total biogenic amines were reduced by up to 33.17%, particularly putrescine, cadaverine, tyramine, and histamine. Regarding product quality, the strain promoted acidification, maintained low water activity, and effectively reduced nitrite levels. Both inoculation levels induced moderate lipid oxidation while preserving the characteristic red color typically associated with nitrite curing. Notably, the lower inoculation level (10 6  CFU/g) achieved an optimal balance between safety enhancement and sensory preservation, while also promoting the release of free amino acids. Statistical modeling identified acidification and precursor depletion as key drivers suppressing nitrosamine formation. Overall, an appropriate inoculation level of L. rhamnosus H7 effectively improved the safety and maintained the quality of dry fermented sausages, demonstrating its potential as a functional starter culture.