Vintage Heinz 57 Ketchup Pickle Factory Worker / Sample Lady Cardinal Uniform Plus Size 18

Rare Vintage Heinz 57 Factory / Sample Lady Uniform Dress in GREAT shape.
Wonderful for a pickle, ketchup, Heinz or uniform collector.
Plus Size 18

I have been searching for information about this retro garment for 2 years and have found absolutely nothing. If you have any knowledge concerning the history of this surprisingly unique item please send me a message.
Thank you. 🙂

Label says:
Cardinal
Tailored
Toronto
Pre – Eminent
Sanforized Shrunk 18