Thank you for your important question.
May Allah, Most High, reward you for your desire to increase in knowledge.
It is permissible to consume food purchased by someone whose majority of their wealth is made up of permissible funds, even if some of it is interest-bearing wealth.
If the majority of their wealth is interest-based, then it is not permissible to eat this food.
(Ibn Abidin; al-Radd al-Muhtar)
Keep in mind the words of the Prophet Muhammad (Allah bless him and give him peace), “A body nourished with haram will not enter Paradise.”
And Allah alone knows best,
[Ustadh] Omar Popal
Checked and Approved by Shaykh Faraz Rabbani