This one gave me a start when I read it, and sent me to my telephone to consult with a few experienced printers. The answers I received were unanimous - this is completely incorrect. Sesame oil is never used by printers - Camellia oil is the product of choice. It leaves no stains in the paper, and will not 'go off' even during hot summer weather.
One can only assume that there was some kind of misunderstanding in the translation between Mr. Tokuno and Mr. Koehler.