My friend (he's in his mid twenties and is currently writing his thesis for his PhD) told us that tortilla chips contain sand. After checking a pack of Doritos he changed it to "all tortila chips apart from Doritos contain sand."
A few weeks ago he told me this amazing fact again, but it had changed to "all Mexican food contains sand".
A childhood belief about nasty food

others believed things like this
- i used to think salt was made of sand— hibiscus
- When my daughter was 3, she saw a cat using a litter box. She thought it was building a sand castle.— Debbie the Bad Swimmer
- When i was 6 years old i had a dog named Sandy. And i thought she was made of Sand.— Billy Bob Joe
- in sting's / the police's song ''roxanne''. I thaught that it was ''rock sand''— wacko zacho
- I believed one of the greatest dangers you could face was quick sand. I was scared to death of it.Anon
- I used to think that if you ate the black bits on chips you would instantly die of cancer.— jayne