In a word, no. Many elements of the periodic table (the heavy ones near the bottom) are so unstable that they only exist for a fraction of a second before they decay into other elements/particles. These elements have only existed for a small amount of time in high energy collision experiments. Therefore I don't think you're fish and chips has any ununoctium in it because you'd have to eat it within 0.89 milliseconds. 

What Rob says s true, but I suppose you really meant the first 92 elements. I reckon that the reply still is no, but most of them certainly would be present in near-homeopathic concentrations (which is one reason to sniff at homeopathy on logical grounds).

However, there are some elements that hardly occur in nature, such as Promethium, Francium, astartine and so on. They are so unstable that they occur so rarely that it is quite likely that you might miss picking up a single atom, even of they are less unstable than unununium.