Many Red Flags Preceded a Recall of Hamburger

ELIZABETH, N.J. — Over the summer, as Americans fired up their grills, the Topps Meat factory here scrambled to produce thousands of frozen hamburger patties for Wal-Mart and other customers, putting intense pressure on workers.

As output rose, federal regulators said in interviews, the company was neglecting critical safeguards meant to protect consumers. Three big batches of hamburger contaminated with a potentially deadly germ emerged from the plant, making at least 40 people sick and prompting the second-largest beef recall in history.