Microbiological aspects of ergo ( ititu) fermentation

Abstract

Ergo is a traditionally cultured milk product which has some resemblance to yoghurt in its curd formation and acidity. Raw milk is allowed to ferment in to ergo for about 24 h at ambient temperature before it is consumed. Time course studies on growth of the microorganisms involved in the culturing of ergo were made. Culturing is carried out by lactic acid bacteria belonging to the genera Lactococcus, Streptococcus, Leuconostoc and Lactobacillus. However, micrococci, sporeformers and coliforms were present in fairly high numbers during the first 14-16 h of fermentation. The lactococci were the most dominant group throughout the fermentation (1 × 105 c.f.u./ml at 0 h and 4 × 109 c.f.u./ml at the end of fermentation (24 h)), followed by streptococci. The yeast population which was about 1 × 101 c.f.u./ml just after milking increased to about 1 × 105 c.f.u./ml at the end of 24 h of fermentation. The total aerobic mesophilic count increased from about 1 × 105 to 4 × 109 c.f.u./ml and at the same time titratable acidity increased from 0.16 to 0.75% with a concomitant decrease in pH.