Hi srijoy Mukherjee

So being a pcmb student is a positive point for you . You get a credit for that . Dairy technology is an under graduate course of B.tech. so your UG in biology degree would be different and this would be different .
Dairy technology is a 4 yr long undergraduate technology engineering course. During each semester, you will  have to face different sets of theoretical subjects as well as practical workshops and lab sessions.
This is  surely an interesting course that you chose .
The eligibility criteria for this course is :

12th science stream students who have passed their 12th board exams from a recognized board are eligible to pursue this course. Only mathematics group students are eligible. This makes you eligible for applying for this course .
But a Minimum marks criteria exists as well . Generally, it is between 40-50% marks in PCM subjects.

I hope I was helpful thank you