Śrī Caitanya Caritamrta · Text Madhya 20.309
দুগ্ধ যেন অম্লযোগে দধিরূপ ধরে ।
দুগ্ধান্তর বস্তু নহে, দুগ্ধ হৈতে নারে ॥ ৩০৯ ॥
dugdha yena amla-yoge dadhi-rūpa dhare
dugdhāntara vastu nahe, dugdha haite nāre
“Milk is transformed into yogurt when it associates with a yogurt culture. Thus yogurt is nothing but milk, but still it is not milk.
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