Abstract: Technology for the separation of bifidobactreial cells is an important intermediate step to obtain the preparation of bifidobacterial products lyophilized. This paper describe a correlation between the harvesting or loss rate of live cells and the survival rate of B.bifidum during centrifugation. Nodified MRS medium as centrifugation vehicle was used to study the effects of centrifuglng force, time and pH in medium on the loss and survival rates of B.bifidum. The optimum conditions for harvesting the highest biomass of the bifidobacteria were also deternined throughout centrifugation. It was shown that once when both centrifugation force and time was increased, the ntalers of living cells lost in supernatant were reduced but at the sane time the survival rate of B. bifidium decreased markedly (P<0. 01). Therefore, the optimim conditions for centrifugation were 3438g (4000r/min) for 10min or 6446g (7500r/min) for 5min. In this case) the highest harvestinq rate of livinq cells was 98 .92% or 98.81%. If given the centrifugation with 3438g for 10min, pH value in media had no siqnificant influence on the harvesting rate of living cells (P>0. 05).

Key words: Bifidobacterium bifidum centrifugation Harvesting rate Loss rate Survival rate,