Seasonal dynamics of microbiota and physicochemical indices in the industrial-scale fermentation of Sichuan Baoning vinegar

• Differences between the microbiomes in every two seasons were observed. • The increase in total acidity of vinegar Pei was lowest in the summer (3.40 g/100g). • Lactic acid and acetic acid contents in raw vinegar from each season were different. We investigated the impact of seasons of the year on microbiota and physicochemical indices of industrial-scale fermentation of Sichuan Baoning vinegar. Illumina HiSeq sequencing results showed significant differences ( P < 0.05) between the microbiomes of vinegar Pei in every two seasons, except for bacterial communities between summer and autumn. Total acid, reducing sugar, starch, and alcohol contents of vinegar Pei from the same sampling day of each season were measurably different. Although total acid content in vinegar Pei was similar at the end of fermentation ( P > 0.05), the increase in total acidity was highest in the autumn. Acetic acid content in raw vinegar was highest in the autumn (3472.42 mg/100 mL), and lowest in the summer (2304.01 mg/100mL). This study provides a theoretical basis for the production of Sichuan bran vinegar with consistent quality and provides insights into the quality control of traditional fermented foods.