I don’t think it’s a prank.
I’m sorry, I don’t believe that story for one second. Ketchup has an acid base - tomatoes. AND it has sweeteners - sugars and/or or corn syrup.
As sure as I’m sitting here typing this answer, I’ll bet that place ”marries” ketchup bottles AND I’ll bet a little more those “married” bottles were not rotated.
“Married” means at the end of the evening, the bottles on the tables are brought to a table and
A] one started bottle is poured into another started bottle.
B] AND/OR a large can of ketchup is opened and that new ketchup was poured on top of the older ketchup.
C] AND/OR the ketchup in that "married" bottle fermented. The ketchup in that bottle “soured” or turned bad.
D] AND/OR those married bottles are not put on the tables to make sure that older ketchup is used first.
OR the company shipping the ketchup, didn’t rotate the ketchup it received from the warehouse where the ketchup was stored.
OR the manufacturer of the ketchup, allowed something to happen or didn’t to get past “Quality Control”.
Thank you for asking your question. I enjoyed taking the time to answer your question. You did a great job - not only for your information, but for every other person interested in reading my answer.
I wish you well!
VTY,
Ron Berue
[Yes, that's my reallastname.]