Temperature Drives Microbial Dynamics during the ripening of Serrano Artisanal Cheese

Abstract

This study investigated the impact of ripening temperature on the microbial diversity of Serrano artisanal cheese (SAC), a raw milk specialty from southern Brazil. Despite its cultural and economic significance, the effects of ripening conditions on SAC microbiota remain underexplored, particularly in unpasteurized dairy products. Cheese maturation was conducted at 5°C, 12.5°C, and 20°C for 60 days, with microbial assessments every 15 days using metabarcoding (16S rDNA and ITS sequencing). The results revealed temperature-dependent shifts in bacterial and fungal communities. Maturation at 5°C favored the proliferation of pathogens associated with raw milk contamination, while higher temperatures reduced pathogenic bacteria and promoted lactic acid bacteria (LAB) (Enterococcus, Lactococcus, Lactobacillus, Leuconostoc, and Streptococcus), which contribute to pathogen inhibition and sensory quality preservation. Physicochemical analyses demonstrated correlations between temperature, humidity, pH, fat, NaCl, and microbial composition. A review of ripening criteria is recommended, including a reduction in the minimum legally required maturation period (from 60 to 30 days) under controlled temperature conditions, as demonstrated in this study, alongside the implementation of technical regulations and knowledge dissemination to ensure product quality and safety.