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

The microbial and some biochemical changes during the fermentation of two E thiopian 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 meso philic bacteria declined during the fermentation period. Lactic acid bacter ia (LAB) reached the maximum count of 5.9 x 10(9) cfu/g at day 4 and the co unt remained >10(8) cfu/g throughout the fermentation. The heterofermentati ve LAB dominated until day 3; thereafter the homolactics dominated the ferm entation. 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 unch anged 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 L AB initiated and dominated the fermentation for the first 2 days and the he terolactics took over thereafter. Both fermentations were accompanied by de clining pH and increasing titratable acidity. Salmonella typhimurium was in hibited during both fermentations within 48 h. Both 'awaze' and 'datta' had low initial contents of available protein and reducing sugars and these di d not show marked differences throughout the fermentation.