Hi,
Its is possible that your grandmother was a Beta Sigma Phi sister, however, sisters sold the cookbooks as fundraisers too. Try e-mailing
membership@betasigmaphi.org, give them her name and ask them to look to see if she was a BSP sister.
Sounds like you have enjoyed the cookbook over the years! BSP sisters across the country could always cook and we always enjoy good refreshments & meals at our meetings!
Let us know what you find.
JudyK