To guide or not to guide? Comparison between guided and spontaneous fermentation of Boletus edulis in laboratory and culinary conditions: impact on microbial population and aromatic compounds

Le résumé fourni par la source

Fermentation is increasingly used in culinary practice to create novel flavors and sensory experiences; however, spontaneous processes performed under poorly controlled conditions may raise concerns regarding microbiological safety and the reproducible development of desirable sensory traits. In this study, spontaneous and guided fermentations of Boletus edulis were carried out in parallel in two production settings: a research laboratory and a professional kitchen in Andalo (Trento, Italy), where the process was performed by an experienced chef. The aim was to assess microbial dynamics, safety-related aspects, and changes in the volatile profile. Mushrooms were fermented with 2.5% NaCl for 6 days, either spontaneously or after inoculation with Lactiplantibacillus plantarum UPCCO 4932. Fermentations were monitored by viable counts, pH measurements, shotgun metagenomics, and volatile compound analysis by HS-SPME/GC-MS. Guided fermentation reduced pH below 4.5 within 48 h in both settings, whereas spontaneous fermentation showed slower acidification. At the end of fermentation, LAB counts reached approximately 8–9 Log CFU/g in all conditions. Shotgun metagenomics confirmed the dominance of the inoculated L. plantarum strain in guided fermentations, while spontaneous samples showed higher taxonomic variability and the presence of undesirable or potentially pathogenic bacteria. These results should be considered safety-related indicators rather than direct evidence of viable pathogens or toxin production. Volatile analysis identified 27 compounds. No significant differences were observed for 1-octen-3-ol and 3-octanone, whereas 3-octanol was higher (p = 0.0282) in guided fermentations. Overall, guided fermentation supported more reproducible microbial and volatile profiles, although further validation is needed before definitive safety conclusions can be drawn.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.