A week? Why would they want to store a week’s worth of food? That would be foolish when they could just use their EBT card to get all the steak and shrimp they want. By then Frma would be right there with kobe beef and sparkling mineral water a plenty.
In a real emergency they'll run out of Wagyu beef in the first day. I hope you're not suggesting these poor people be stuck with domestic filet mignon.
My favorite line in World War Z - "by New Year's there was plenty to eat." The little girl narrator was referring to people who were too squeamish to become cannibals and so became food...