Escherichia coli O157:H7 United States · 1992 to 1993

E. coli O157:H7 outbreak linked to hamburgers from a fast food restaurant chain, western United States, 1992 to 1993

CDC reported more than 500 laboratory-confirmed infections in Washington, Idaho, California and Nevada, with 4 deaths, three in Washington and one in California. Illness was linked to regular-sized hamburger patties from a restaurant chain identified in the report as chain A. CDC wrote that undercooking of hamburger patties likely played an important role. CDC says PulseNet was created after a 1993 E. coli O157:H7 outbreak that caused more than 700 illnesses and four deaths.^1,2

Counts as reported on 16 April 1993.¹ Food vehicle: Undercooked regular-sized hamburger patties served at a fast food chain.

Timeline

1. 15 November 1992Start of outbreak period covered by the MMWR report.¹
2. 13 January 1993A physician reported a cluster of haemolytic uraemic syndrome cases to the Washington Department of Health.¹
3. 18 January 1993A multistate recall of unused patties began.¹
4. 16 April 1993CDC published its update in MMWR.¹
5. 1996CDC PulseNet network began.²

Regulatory and legal outcomes

1. 16 April 1993US Food and Drug Administration (as reported by CDC). FDA issued an interim recommendation to raise the internal temperature of cooked hamburgers to 155 degrees Fahrenheit.¹

Sources

1. US Centers for Disease Control and Prevention, MMWR 42(14), Update: Multistate Outbreak of Escherichia coli O157:H7 Infections from Hamburgers, Western United States, 1992 to 1993 (16 April 1993)
2. US Centers for Disease Control and Prevention, About PulseNet (31 August 2026)