Some microbiological and biochemical studies on the fermentation of 'awaze' and 'datta', traditional Ethiopian...

The microbial and some biochemical changes during the fermentation of two Ethiopian condiments were studied. The aerobic mesophilic microflora of the ingredients of 'awaze' were dominated by Bacillus species (1.1 x 10(6) cfu/g) and lactic acid bacteria (4.5 x 10(4) cfu/g). The counts of aerobic mesophilic bacteria declined during the fermentation period. Lactic acid bacteria (LAB) reached the maximum count of 5.9 x 10(9) cfu/g at day 4 and the count remained > 10(8) cfu/g throughout the fermentation. The heterofermentative LAB dominated until day 3; thereafter the homolactics dominated the fermentation. Yeasts appeared at day 6 and increased to 2.5 x 10(6) cfu/g. In 'datta' fermentation, the count of aerobic mesophilic bacteria remained unchanged during the fermentation. LAB initiated the fermentation at a level of 7.1 x 10(4) cfu/g and reached 1.2 x 10(9) cfu/g at day 7. The homolactic LAB initiated and dominated the fermentation for the first 2 days and the heterolactics took over thereafter. Both fermentations were accompanied by declining pH and increasing titratable acidity. Salmonella typhimurium was inhibited during both fermentations within 48 h. Both 'awaze' and 'datta' had low initial contents of available protein and reducing sugars and these did not show marked differences throughout the fermentation.