Impact of Probiotic Fermentation with Indigenous Lactococcus lactic LL16 on the Safety of Lithuanian Dried Chanterelles

The study evaluated the impact of Lactococcus lactis LL16 fermentation on the safety parameters of Lithuanian dried chanterelle mushrooms. The chanterelles were handpicked, dried, homogenized, and sterilized before use. For solid-state fermentation, the chanterelle powder was mixed with sterilized water (ratio 1:2 w/w), inoculated with a 9.0 log10CFU/mL bacterial concentration of revitalized L. lactis LL16 (previously isolated from locally sourced raw bovine milk, GenBank: JARHUB000000000). Non-fermented chanterelle mushroom powder served as the control. LAB counts were determined by plating and counting, and were significantly increased in the fermented samples (7.42 ± 0.00 Log CFU/g) in contrast to being undetectable in the non-fermented control. These results correlated with a significant pH decrease in the fermented sample (from 6.03 ± 0.02 to 5.64 ± 0.20). Antimicrobial activity was assessed by agar diffusion against 8 common foodborne pathogens. The zones of inhibition were scaled from - to +++. Brochothrix thermosphacta, Pseudomonas aeruginosa, and Pseudomonas fibrescens showed strong inhibition (+++), while Listeria monocytogenes showed mild inhibition (+), Staphylococcus aureus and Bacillus cereus showed very weak inhibition (+/-), and no visible inhibition occurred against E. coll, and Salmonella typhimurium. These findings demonstrate that fermentation with L. lactis LL16, compared to the non-fermented control, effectively improves the microbial safety of dried chanterelles.