Shocking they used lie detector test back in the day for a minimum wage jobs in a food chain store as if it is high end security related job. 

Interesting!

During lying, the blood pressure increases conventionally but for someone who has irregular blood pressure or circumstantially if spiked, the lie detector machine is going to say it lied. That's the drawback of the system. 

Good, fate saved you from getting that job in a weird way. 

Food processing of potatoes to such an extent that they photocopied every potato to give the same taste. That would be my guess!