Most organized I've ever experienced.
I recomend office casual, dont overdress. A pair of safety boots may be required if they take you for a tour of the warehouse.
Its fairly relaxed, but professinol at the same time. Just do what they ask and answer the questions to the best of your ability.
Sysco does have a team of genuine people who are easy going, the one who interviewed me resigned but Im sure they found a good replacement.