Comparative analysis of the effect of herbs on diverse microbiological properties of yoghurt at different storage periods

Yoghurt is rich in nutrients like potassium, calcium, protein and vitamin B and has beneficial effects on human health by supplying prebiotic and probiotic bacteria. It helps to strengthen the immune system, improves lactose digestion and gastrointestinal conditions including lactose intolerance, constipation, diarrhoea, colon cancer, inflammatory bowel disease and allergies. Six batches of different herbal probiotic yoghurt were prepared using fresh milk by inoculated with 4 per cent of yoghurt cultures containing Lactobacillus delbrueckii subsp. bulgaricus, and Streptococcus salivarius subsp. thermophilus. In the viability study of probiotics organisms, it was revealed that there was significant (P˂0.05) reduction in the viability of Streptococcus salivarius subsp. thermophilus and Lactobacillus delbrueckii subsp. bulgaricus (log10cfu/ml) were noticed in all the herbal yoghurt including plain yoghurt during storage period of 21days and wherein the reduction was high in AGY, CIY and HSY compared with PY and ABY and this may be attributed to slight acidic nature of herb. However the count of probiotic strains was maintained at 7 log units for all herb treated yoghurts throughout storage period of 21 days.