POPULATIONS OF LACTOBACILLUS-DELBRUECKII SSP BULGARICUS, STREPTOCOCCUS-THERMOPHILUS, LACTOBACILLUS-ACIDOPHILUS AND BIFIDOBACTERIUM SPECIES IN AUSTRALIAN YOGURTS

Fifty commercial yoghurts, representing 16 Australian manufacturers, a nd claiming to contain the probiotic bacteria, Lactobacillus acidophil us and Bifidobacterium species, were examined for the viable populatio n of these species as well as the yoghurt culture species, Lactobacill us delbrueckii ssp. bulgaricus and Streptococcus thermophilus. The via ble populations of L. delbrueckii ssp bulgaricus and S. thermophilus e xceeded 10(7) cfu/g in 54% and 68% of the samples, respectively. The v iable populations of L. acidophilus and Bifidobacterium species exceed ed 10(6) cfu/g Only in 24% and 14% of the samples, respectively.Yoghur ts possessing high populations of L. delbrueckii ssp bulgaricus tended to be more acid (pH < 4) and contained L. acidophilus and/or Bifidoba cterium species at populations less than 10(6) cfu/g.