Explaining a layoff without sounding bitter after 18 years as a line cook

I have an interview next week and I am unsure how to explain why I left my last job as a line cook. I do not usually post, so bear with me. I do not want to blame the company. What do you say?

Keep everything in writing and save the confirmation numbers. It made the follow-up calls so much easier.

Practise it out loud with a friend. Mine felt natural after the third try.