A grocery crisis is brewing as a major food distributor's IT issues leave shelves empty at some supermarkets

A shopper walks past refrigerated groceries at a supermarket.

Spencer Platt/Getty Images

• UNFI, a major food distributor, said Monday that its IT system had "unauthorized activity."
• The issue affected grocery deliveries to some supermarkets, the company said.
• Shelves at some Whole Foods stores appeared mostly empty over the weekend in social media posts.

Shelves at some grocery stores are sitting empty after an IT problem at a major food distributor.

United Natural Foods...