I realize that we can prefix the names of some food items such as "sushi", "sashimi", "mizu", and others with "o".
However, there are other food items, such as "tamago", for example, whose names cannot be prefixed with "o".
How can we foreigners decide when it's proper and when it's not proper to prefix the name of a food item with "o"?
Also, when prefixing food item names, is it お or を ?
Actually, I think it's probably the honorific お , but I just want to make sure.
ありがとうございます