Quantitative and qualitative studies of the microflora of barley malt production

摘要

Populations of aerobic heterotrophic bacteria, mycelial fungi and yeasts occurring in malting barley were estimated by a plate technique and scanning electron microscopy. There was an increase in the total number of micro‐organisms during germination, although populations declined after kilning. Bacteria dominated on all samples, with progressively lower populations of yeasts and filamentous fungi. There was no obvious spatial distribution of micro‐organisms on the samples although there appeared to be high populations of bacteria and fungal hyphae on the inner surface of the kernels. The dominant groups of aerobic heterotrophic bacteria were presumptively identified asAlcaligenessp.,Arthrobacter globiformis, Clavibacter iranicum, Erwinia herbicola, Lactobacillusspp. andPseudomonas fluorescens.The principal filamentous fungi were identified asAiternaria alternata, Aspergillus glaucus(group),Cladosporium macrocarpum, Epicoccum purpurascens, Fusarium avenaceum, Geotrichum candidumandPenicilliumspp. The yeasts isolated most frequently wereCandida catenulata, C. vini, Debaryomyces hansenii, Hansenula polymorpha, Kloeckera apiculata, Rhodotorula mucilaginosa, Sporobolomyces roseusandTrichosporon beige