The zarIra avidya-jal is technically a pada, a piece of Bengali poetry. I can assure everyone it most certainly is not in Sanskrit, and the word mantra is not customarily used for the such, regardless of how one might explain the meaning of the word mantra.

In Vrindavan at festivals, Gaudiya Vaisnavas commonly chant a rather lengthy Jaya-dhvani before taking prasad. Then, there's another cute chant:

rAma kaha sukhe bhaje, kRSNa kaha duHkha yAYa |
mahA-prasAda pAo sAdhu, prema prIti lAgAi ||

“Say Rama and worship with joy, say Krishna and miseries flee.
O saints, take the most glorious prasad – prema and priti are available!”

That is in Bengali, too. One may also chant or remember any other songs or verses, such as the descriptions of Sri Caitanya Mahaprabhu's praising Jagannatha's maha-prasada in Caitanya-caritamrita, Antya-lila, chapter 16.