Behavior of the complex micro-ecology in maize and rye flour and mother-dough for broa throughout storage

Besides water, maize and rye flour are the main constituents of broa a unique sourdough bread, manufactured following traditional protocols at the farm level in Portugal. Mother-dough, i.e., a piece of leavened dough kept aside from batch to batch under refrigeration conditions, constitutes the only starter culture used throughout breadmaking. Maize and rye flour, as well as mother-dough, were accordingly assayed for their microbiological profiles throughout storage time, to characterize the evolution in viability of the adventitious microorganisms: total viable counts, as well as viable yeasts, molds, gram-negative rods, gram-positive rods (endospore-forming and nonsporing) and gram-positive cocci (catalase+ and catalase). In general, all microbial groups exhibited an outstanding resistance to storage, so use of mother-dough appears technologically effective in this form of breadmaking, and an appropriate storage of flour does not convey any important changes to their microbiological profile.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, on a volunteer basis, in supplying samples for analysis. Financial support for author J. M. R. was provided by a Ph.D. fellowship within the program PRAXIS XXI – ref. PRAXIS XXI/BD/16060/98, administered by Fundação para a Ciência e a Tecnologia (Portugal) and supervised by author F. X. M. Partial financial support was received within program PAMAF – IED, through research grant “Pão de milho: caracterização do processo tradicional de produção e melhoramento tecnológico” – ref. PAMAF 1022, administered by Ministério da Agricultura, Desenvolvimento Rural e Pescas (Portugal) and coordinated by author F. X. M