Tricholoma matsutake polysaccharides promote physiological germination and metabolic reactivation of Bacillus cereus spores: Mechanisms and application in milk preservation.

Spore-forming bacteria threaten food safety due to their extreme thermal resistance. Here, Tricholoma matsutake polysaccharides (TMP, 1% w/v) were identified as potent germination inducers for Bacillus cereus spores, enabling an effective germination-inactivation strategy. Across tested strains, TMP showed broad but strain-specific germination-inducing activity. TMP treatment reduced OD600 by more than 34% within 2 h, outperforming classical germinants (e.g., L-alanine, inosine). Physiologically, TMP reduced refractility and induced controlled ion release, with conductivity approximately twofold higher than the control, while triggering typical structural remodeling. Flow cytometry indicated no severe propidium iod(PI)-detectable membrane damage, and SEM confirmed germination-associated structural changes. Transcriptomic analysis revealed 479 differentially expressed genes (206 upregulated), with significant enrichment in germination machinery (e.g., gerQ, cwlJ, and sleB), nutrient transport systems, and energy metabolism (e.g., TCA cycle and oxidative phosphorylation). Notably, TMP-assisted mild pasteurization showed the strongest suppression of B. cereus outgrowth during 5-day milk storage, maintaining lower viable counts than the control, fructose, and L-alanine/inosine groups. Unlike nutrient germinants, TMP did not support post-germination proliferation. These findings establish TMP as a promising natural agent for enhancing microbial safety in dairy products.