There will be challengers to the title of the world's oldest Jew. But leave aside disputes over the provenance of birth certificates. There is one lesson from Mary Rothstein's story.
The secret of her longevity is not, as her daughter put it, that: "She's never drunk, never smoked and worked very hard." It is, surely, that: "She's never eaten in an ordinary restaurant, only a Jewish restaurant. She's very, very kosher."

A diet of chicken soup, lokshen and kneidlach, followed by salt beef and latkes, is the recipe for good health. As Eubie Blake put it on his 90th birthday: "If I'd known I was going to live this long, I'd have taken better care of myself".