Microbial community succession and functional potential during processing and storage of cooked ham assessed by shotgun metagenomics.

Abstract

Wet-cured ham is a ready-to-eat meat product in which microbial communities contribute to desired product characteristics related to product quality, while also presenting as a spoilage risk. Microorganisms are introduced early during the live brining of raw meat, with the brine representing a long-standing, complex and active culture that influences nitrate generation, preservation, and flavour development. To support quality control and identify early indicators of spoilage, this study investigated taxonomic and functional microbiome changes across production stages, from brining and cooking to cold storage, slicing, and packaging under modified atmosphere. Using metagenomics, we characterised microbial community composition and functional profiles across 67 samples from raw ingredients, intermediate production steps, and final products. Microbial communities differed significantly between stages, despite sharing a related taxonomic structure. Brining markedly reduced diversity, and cooking further decreased richness and evenness. A set of 28 taxa was consistently detected across stages, though their relative abundance varied. Latilactobacillus curvatus was abundant prior to cooking but declined sharply afterwards, while Arthrobacter rhombi, initially rare, became dominant in the cooked product. During chilled storage, microbial succession continued, with some taxa re-emerging after being nearly eliminated by cooking. Functional gene profiling revealed distinct metabolic pathway shifts across stages, particularly involving respiration, amino acid metabolism, and fermentation. These findings provide a detailed baseline of microbial and functional dynamics in the production and storage of wet-cured ham. The results offer a foundation for spoilage risk assessment and contribute to the development of microbiological monitoring strategies to support product safety and shelf-life management.