Apparently this is so common, there is a term for it: simulacra, or more specifically, pareidolia. I had no idea this was an actual thing, I just got curious and googled "religious images in food". I suppose since I am totally areligious, I see this type of phenomena as completley ludicrous and I would probably not notice the appearance of Jesus' visage in my cuisine. But apparently, the human mind easily percieves familiar patterns or images, and devout people probably look a lot at depictions of Mary, et. al. and therefore recognise these patters in everyday places like scorch marks on a tortilla. And since these people are more devout, they ascribe meaning to such imagery and it becomes "a sign". And I was wrong about it only being Christian imagery; the word in arabic for "Allah" is seen so often in food that is has become fairly commonplace.
This made me wonder, have non-secular images also appeared in food? Perhaps discovered by someone with some other type of visual fixation? And lo and behold, turns out that the image of Elvis has been seen quite a bit in food, as well as various US presidents. A knot in a tree trunk that looked like a monkey nearly caused a riot in Singapore in 2007.
This investigation has led me to beleive that the reason I have never percieved any images in my food is because I am not fixated on any particular imagery...I don't have any strong beleifs about a particular person or idea and I don't frequently view any kind of imagery, except maybe South Park. I'm probaly more likely to see Stan Marsh on a marshmallow...if I ate marshmallows. Which is kind of a releif, actually.
I'll leave you with my favourite image of Jesus, though I hope it's not something you would eat:
