Salmonella Outbreaks Linked to Beef, United States, 2012-2019

Abstract

The Centers for Disease Control and Prevention (CDC) has identified nontyphoidal Salmonella as one of the top five pathogens contributing to foodborne illnesses in the United States. Beef continues to be a common source of Salmonella outbreaks, despite the implementation of interventions at slaughter and processing facilities to reduce contamination of beef. We described Salmonella outbreaks linked to beef in the United States during 2012-2019, examined trends, and identified potential targets for intervention and prevention strategies. We queried CDC's Foodborne Disease Outbreak Surveillance System (FDOSS) for all foodborne nontyphoidal Salmonella outbreaks linked to beef as the single contaminated ingredient or implicated food, with the date of first illness onset from 2012 to 2019. Information on antimicrobial resistance (AR) for outbreak-related isolates was obtained from CDC's National Antimicrobial Resistance Monitoring System (NARMS). We calculated the number of outbreaks, outbreak-related illnesses, hospitalizations, and deaths overall, by beef processing category and Salmonella serotype. During 2012-2019, 27 Salmonella outbreaks were linked to beef consumption, resulting in 1103 illnesses, 254 hospitalizations, and two deaths. The most common category of beef implicated was nonintact raw, ground beef (12 outbreaks, 44%), followed by intact raw (six outbreaks, 22%). Ground beef was responsible for the most illnesses (800, 73%), both of the reported deaths, and was the source of the largest outbreak. AR data were available for 717 isolates from 25 (93%) outbreaks. Nine (36%) of these outbreaks had isolates resistant to one or more of the antibiotics tested by NARMS, of which eight (89%) contained multidrug-resistant isolates. Several outbreaks reported highlight challenges faced during investigations, areas where further research may be warranted, and opportunities to prevent future outbreaks along the farm-to-fork continuum.

Keywords: Antimicrobial-resistance; Beef; Ground beef; Outbreaks; Prevention; Salmonella.

Figure 1.

Number of Salmonella outbreaks linked to beef by state, United States, 2012–2019. There were 19 single-state outbreaks and 8 multistate outbreaks. Multistate outbreaks are counted as an outbreak for each state that reported a case. Single-state outbreaks occurred in 13 states: California (1), Colorado (1), Connecticut (2), Georgia (1), Minnesota (2), New Mexico (1), New York (1), Ohio (2), Oregon (1), Tennessee (2), Virginia (1), Washington (1), Wisconsin (3).

Figure 2.

(a) Number of Salmonella outbreaks linked to beef, by year and beef type, United States, 2012–2019. (b) Number of Salmonella outbreak-related illnesses linked to beef, by year and beef type, United States, 2012–2019.

Figure 3.

(a) Number of Salmonella outbreaks linked to beef, by month and beef type, United States, 2012–2019. (b) Number of Salmonella outbreak-associated illnesses linked to beef, by month and beef type, United States, 2012–2019.

Figure 4.

Percentage of nontyphoidal Salmonella clinical isolates with antimicrobial resistance^A from outbreaks linked to beef as the single contaminated ingredient or implicated food (n = 25), National Antimicrobial Resistance Monitoring System, (n = 117), United States, 2012–2019. ^A No isolates showed resistance to azithromycin, ciprofloxacin, or meropenem.