Microbial profile and biogenic amines content in Italian craft beers

This study evaluated the occurrence of biogenic amines (BAs) in 80 Italian craft beers from eight different styles, using high-performance liquid chromatography (HPLC). Microbiological and physicochemical analyses were performed to assess potential correlations with BAs accumulation. Yeasts were present in all samples with a concentration ranging from 2.12 to 5.29 log CFU/mL, lactic acid bacteria (LAB) and acetic acid bacteria were detected exclusively in spontaneously fermented beers, with values of 3.44 ± 0.96 log CFU/mL and 3.26±0.07 log CFU/mL, respectively. Spontaneously fermented beers exhibited the highest total BAs content, due to elevated levels of histamine (up to 25.8 mg/L). Agmatine and putrescine were detected in all beers, with median concentrations of 4.88 mg/L and 4.06 mg/L, respectively. Tyramine was present in 92.5% of the samples, while histamine and cadaverine were found in over 60% of beers, although generally at lower concentrations. The obtained results revealed positive correlations between LAB counts and BAs levels, while pH showed a negative correlation. These results highlighted the influence of fermentation type, microbial populations, and brewing parameters on BAs formation. Although all samples were below the general safety threshold of 100 mg/L total BAs, ongoing monitoring is recommended, especially for sensitive consumers. • Agmatine was the main BAs detected • The pH showed a negative correlation with TYR, HIS and PUT concentrations • A positive correlation was found between TYR, HIS, and PUT and the total acidity