McDonald’s has restarted sales of its Quarter Pounder burgers nationwide after ruling out its beef patties as the cause of a recent E. coli outbreak that led to one death and numerous illnesses. The Colorado Department of Agriculture (CDA) confirmed that samples of the beef patties tested negative for the bacteria, and further testing by the CDA is not planned.
Quarter Pounder Sales Suspended Amid Outbreak
Last week, McDonald’s temporarily halted Quarter Pounder sales in roughly 20% of its US locations as a precaution following the outbreak. The company has since determined that the contamination was limited to a specific ingredient in certain regions and has assured that any affected products have been removed from its supply chain. “We remain confident that the contaminated product related to this outbreak has been isolated,” stated Cesar Piña, McDonald’s North America Chief Supply Chain Officer.

Onion Supplier Connection to E. coli Outbreak
An investigation by the US Food and Drug Administration (FDA) identified slivered onions used in Quarter Pounders as a potential contamination source. McDonald’s has since cut ties with the supplier, Taylor Farms’ Colorado Springs facility, and removed slivered onions from its supply chain. The 900 affected restaurants will now serve Quarter Pounders without slivered onions.
Health Precautions and Legal Actions
In response to the outbreak, the Centers for Disease Control and Prevention (CDC) advised anyone experiencing symptoms such as diarrhea, fever, and vomiting after consuming a Quarter Pounder to seek medical advice. Although most individuals recover within five to seven days, some severe cases may require hospitalization. McDonald’s also faces several lawsuits from customers who became ill.
Impact on McDonald’s Sales and Stock
Since the CDC’s report of the outbreak, McDonald’s shares have dropped by over 7.5%. The company, along with other fast-food giants, continues to feel economic pressure as surging costs impact its lower-income customer base. In July, McDonald’s reported a surprising global sales decline, marking its first quarterly drop in more than three years.
