ENUMERATION OF FUNGI IN BARLEY

Estimation of fungal contamination of barley grain is important as cer tain fungi can proliferate during the malting process. The following f actors which may affect the enumeration of fungi were evaluated: dilut ion versus direct plating, presoaked versus unsoaked grain, five cultu re media: potato dextrose agar (PDA), acidified Czapek-Dox agar (ACA), pentachloronitrobenzene agar; (PCNB) dichloran rose bengal chloramphe nicol agar (DRBC) and malt salt agar; two disinfectants' ethanol/water (80:20 v/v) and sodium hypochlorite (3.5% w/v in H2O). Two barley sam ples, one having a high incidence of storage fungi and one with a high incidence of field fungi were used and most fungi were identified to species level. Results showed that direct plating was superior to dilu tion plating for assessing the mycoflora of barley. Unsoaked grain gav e significantly higher counts than presoaked grain in the case of Alte rnaria alternata, Rhizopus oryzae, Epicoccum nigrum and Mucor spp. Pre soaked grain resulted in higher counts of Penicillium spp. Chlorine di sinfection resulted in significantly higher counts of Aspergillus flav us, Eurotium spp. and Penicillium spp. Ethanol disinfection resulted i n higher counts of Mucor spp., Phoma sorghina, Rhizopus oryzae and Asp ergillus restrictus. PDA and ACA, in general gave some what better res ults than DRBC for both field and storage fungi. PCNB consistently gav e the highest Fusarium counts. More than thirty fungal genera were fou nd in the two samples. (C) 1997 Elsevier Science B.V.