Joan Corbett was named 'Miss Mayonnaise' while her twin sister, Jean, was given the title of 'Miss Salad Dressing'.
Los Angeles Times - June 11, 1952
Pasadena Independent Sun - June 8, 1952
Here's a better picture of the twins.
And here they are in a 1954 ad for Chesterfield Cigarettes.
The Burbank High School 'In Memoriam' blog
has some biographical info about them:
Jean Corbett, 68, died April 29, 1999, in Kauai, Hawaii. Mrs. Corbett and her twin sister, Joan, were born in Burbank. Jean Corbett was a resident for 62 years.In the 1950's, the Corbett twins appeared in commercials, theater and films with such stars as Bob Hope and Frank Sinatra. They graduated from Burbank High School in 1949. They were dancers at Ken Murray's Blackouts. Jean was the cover girl for the 1955 opening of the Riveria Hotel, in Las Vegas. She is survived by her daughter, Lori Williams. Joan Corbett preceded her sister in death. A memorial service was held April 29 in Kauai. The Neptune Society, Kauai was in charge of the arrangements.