Manufacturers: Syracuse China and Unknown (Albert Pick & Co. distributor)
User: Kellogg Company
Date of Syracuse plate: 1925
Date of Albert Pick & Co. celery: Circa 1920
Notes: Kellogg corporate web site
From the Wikipedia: "Kellogg's was founded as the Battle Creek Toasted Corn Flake Company on Feb. 19, 1906, by Will Keith Kellogg as an outgrowth of his work with his brother John Harvey Kellogg at the Battle Creek Sanitarium following practices based on the Seventh-day Adventist Christian denomination."
From the Kellogg Company's timeline/history page, "W.K. Kellogg opened the 'Battle Creek Toasted Corn Flake Company' and used an advertising image that matches that on this celery tray except for the word "Sanitas" preceding Toasted Corn Flakes. By 1914, when their corn flakes were marketed in Canada, the "Sanitas" had disappeared from their branding.
The company produced and marketed the hugely successful Kellogg's Toasted Corn Flakes and was renamed the Kellogg Company in 1922.
The plate and celery dish both have dark green curlicue lines on the rim (with an orange or light red line in between) that are interrupted by the image of a box of Kellogg's Toasted Corn Flakes (on the celery) and Kellogg's Corn Flakes (on the plate).
For more info:
Kellogg Company, by Syracuse China