I always recite the mantra to purify our fault of eating meat (the non-virtous action, killing) this mantra blesses the sentient beings which we are eating and provide them a good rebirth
Om Abira Khe Tsara Hung (× 7)
before reciting any prayer because no matter what we eat, sentient beings are going to be sacrifice , intentionally or unintentionally, such as eating veggie, the farmers are going plough the land, spray pesticide and more.
As a Buddhist we should always set priorities for our Guru, Buddha, Dharma, and Sangha before us because they are the ones that are going to pull us out from the hell of samsara. When we take our meals, we should always think of offering them to our Guru and Buddhas, no matter what type of food we are taking, good or bad, we should offer them before eating, because a guru and Buddhas will not choose what to accept when a student offer the offering with a sincere heart without any sense of ego. The guru and Buddhas will only bless us.