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Quantitative Analysis of Histidine Decarboxylase Gene (hdcA) Transcription and Histamine Production by Streptococcus thermophilus PRI60 under Conditions Relevant to Cheese Making

2011; American Society for Microbiology; Volume: 77; Issue: 8 Linguagem: Inglês

10.1128/aem.02531-10

1098-5336

Franca Rossi, Fausto Gardini, Lucia Rizzotti, Federica La Gioia, Giulia Tabanelli, Sandra Torriani,

Probiotics and Fermented Foods

This study evaluated the influence of parameters relevant for cheese making on histamine formation by Streptococcus thermophilus. Strains possessing a histidine decarboxylase (hdcA) gene represented 6% of the dairy isolates screened. The most histaminogenic, S. thermophilus PRI60, exhibited in skim milk a high basal level of expression of hdcA, upregulation in the presence of free histidine and salt, and repression after thermization. HdcA activity persisted in cell extracts, indicating that histamine might accumulate after cell lysis in cheese.