resumo
A thorough microbiological study of maize and rye flours, and sourdoughs obtained therefrom for eventual manufacture of broa - a dark sour bread typical in Northern Portugal, following artisanal practices, was carried out. Towards this purpose, samples were supplied by 14 artisanal producers, selected from 4 sub-regions, during two periods of the year. Total viable counts, as well as viable mesophilic and thermophilic microorganisms, yeasts and molds, Gram(-) rods, endospore-forming and non-sporing Gram(+) rods, and catalase(+) and catalase(-) Gram(+) cocci were assayed for. The comprehensive experimental dataset unfolded a unique and rather complex wild microflora in flours and sourdoughs throughout the whole region, which did not discriminate among sub-regions or seasons, or flour source for that matter. However, fermentation played a major role upon the numbers of the various microbial groups: the viable counts of yeasts, lactobacilli, streptococci, lactococci, enterococci and leuconostocs increased, whereas those of molds, Enterobacteriaceae, Pseudomonadaceae, staphylococci and micrococci decreased. (C) 2012 Elsevier Ltd. All rights reserved.
palavras-chave
STREPTOCOCCI; ENUMERATION; IDENTIFICATION; DOUGHS; AGAR; CORN
categoria
Biotechnology & Applied Microbiology; Food Science & Technology; Microbiology
autores
Rocha, JM; Malcata, FX
Grupos
agradecimentos
Several members of the Regional Directorate of Agriculture of Entre-Douro-e-Minho (DRAEDM, Portugal) and several local farmers are hereby gratefully acknowledged for their cooperation in supplying samples for analysis. Financial support for author J. M. R. was provided by a Ph.D. fellowship within program PRAXIS XXI - ref. PRAXIS XXI/BD/16060/98, administered by Fundacao para a Ciencia e a Tecnologia (Portugal) and supervised by author F. X. M. Partial financial support was received within program PAMAF - IED, through research grant