When is tripe safe to eat?

I've recently got my hands on a few tripe rations. I've been told by a few friends that it's a good food source in the early game. Of course, I eat some and promptly begin vomiting. I know that you can polymorph the ration or yourself to make it safe to eat, but I don't really want to waste charges on such a menial thing. So, my question is, when is tripe safe to eat, and/or how can you make it safe without polymorphing?

Solution 1:

Tripe rations, like food rations and several other types of food items, is generally safe to eat. More specifically, when you eat it the game rolls to see if the food is rotten. Cursed food is generally more likely to be rotten.

Unless you are an orc or canine, tripe has a higher than normal chance of causing nausea, at 50%.

Basically, there is no specific time or time frame when tripe rations are more or less safe to eat.

More information can be found on the wiki pages for food and tripe.