Effects of Cold Smoking on the Microbiological Characteristics and Volatile Compounds of a Formaella-Type Hard Ewe’s Milk Cheese

The effect of cold smoking on the physicochemical, microbiological, and aromatic properties of Formaella-type cheese has not been previously investigated. In this study, experimental Formaella-type hard cheeses (≤38% moisture) were produced using a multistep high-temperature cooking process and subjected to weak (20 min) and intense (60 min) cold smoking, alongside an unsmoked control. Cheeses were analyzed before and after smoking and during refrigerated storage (up to 90 days). Smoking significantly influenced pH, water activity, and colour parameters, with intensively smoked cheeses exhibiting lower pH, reduced lightness (L*), and increased redness (a*) and yellowness (b*). Microbiological analyses revealed low viable counts across all samples, attributed to severe cooking steps and vacuum storage. Smoking, particularly at high intensity, significantly reduced total mesophilic counts and enterococci, while Enterobacteriaceae, staphylococci, yeasts, and moulds were not detected after manufacture. The dominant microbiota consisted mainly of lactic acid bacteria, identified by MALDI-TOF MS, including Enterococcus durans, Ent. faecium, Leuconostoc lactis, Leuconostoc mesenteroides, Streptococcus thermophilus, Lacticaseibacillus rhamnosus, and Lactobacillus curvatus. Headspace-SPME-GC-MS analysis identified 75 volatile compounds, with free fatty acids, ketones, aldehydes, and lactones as the predominant groups. Smoking introduced characteristic phenolic and furan derivatives associated with smoky aroma. Overall, smoking intensity modulated microbial dynamics and aroma development without compromising microbiological quality.