Food Trivia

Food that is the symbol of hospitality
The pineapple I think (from a quiz I did some time ago
Additionally (and conversely), serving shoulder of beef (especially cold) is a sign of inhospitality and is the derivation of the phrase 'Giving someone the cold shoulder'

Food that last the longest
"The ancient Egyptians loved sweets. Archeologists once found a 3,300-year-old jar of honey in a tomb.
"…the Tomb of Tutankhamun…honey that was almost liquid but still preserved it scent after thousands of years."Honey never goes bad, so the honey found in King Tutankhamen's tomb was still edible after thousands of years.

Most radioactive food
I'm not sure how it compares but I'm sure that cooking food makes a significant difference. Not sure why you would cook a brazil nut though. The reason I say this is that several years ago I remember seeing it on TV. A geiger counter scanned some potatoes, hot oil and chip pan etc.... There was either very little reading or none at all from everything it was pointed at. The potatoes were turned into chips and suddenly they were significantly more radioactive than before. The more and more they were cooked, and the browner and then blacker they became, the higher the geiger counter registered. I understood it was down to the formation of carbon ( the pure element - maybe a specific isotope ) out of the carbon compounds found in all living things. I'm sure some comments were made at the end of the programme suggesting that consuming very large quantites of very burnt toast could probably be detrimental to health because of the radiation levels. I've also seen (heard) a geiger counter click loud and frequent when pointed at a burning cigarette

World's most expensive food
Truffles and Beluga caviar are way out of most people's reach, but the most expensive food item in the world, ounce for ounce, is the spice Saffron.