Food Safety and Inspection Service

U.S. DEPARTMENT OF AGRICULTURE

Salmonella Newport Outbreaks 

Associated with Ground Beef

Outbreak Investigation After-Action Report, 2016-2019 

Highlights

• A strain of Salmonella Newport caused reoccurring 

human infections and two outbreaks associated with 

ground beef.

• There were over 100 illnesses for each outbreak (106 

in outbreak 1 and 436 in outbreak 2), which is 

unusual for ground beef outbreaks.

• The investigations prompted a government-industry

collaboration on innovative methods of obtaining 

shopper history. Shopper history best practices and 

success stories are highlighted in an article on the

Association of Food and Drug Officials webpage. 

What Happened?

From 2016 to 2019, in collaboration with public health 

partners, the Food Safety and Inspection Service (FSIS) 

investigated two Salmonella Newport outbreaks: 

• The majority of reported ill people lived in the 

Southwestern area of the United States. 

• The analyzed isolates did not show any predicted 

antimicrobial resistance. 

• At least 80% of the ill people had eaten ground beef 

in the week before illness. At least one ground beef 

sample tested positive for Salmonella Newport and 

was closely related by whole genome sequencing 

(WGS) to clinical isolates. 

• Ill people reported eating or possibly eating 

undercooked ground beef. 

Outbreaks at a Glance

Illnesses 542 

States included 36

Hospitalizations 163

Deaths 1 

Response at a Glance

Ill people with 

documentation to 

identify foods

40 

Recall or Public 

Health Alert

Yes

Process improvement

• This Salmonella Newport 

strain associated with 

ground beef has been 

characterized as a 

reoccurring strain 

because it has caused 

repeated outbreaks of 

human illnesses with 

similar epidemiologic 

characteristics. Every 

month, FSIS monitors 

selected Salmonella 

serotypes, including 

Newport, for directional 

changes and trends, and 

compares them to a 3-

year historical average 

for that particular 

serotype.
How Do the Two Outbreaks Compare?

The first outbreak, with illness onset dates ranging from October 4, 2016 to July 19, 

2017, included 106 people from 21 states. The second outbreak had illness onset dates 

from August 5, 2018 to February 17, 2019 and included 436 cases from 31 states. The 

age range was similar (<1-88 and <1-99) for both outbreaks with a median age of 44 for 

the first outbreak and 42 years for the second outbreak. Forty eight percent (42/88) of 

the cases were hospitalized in the first outbreak, with one reported death, and 33%

(121/363) of cases in the second outbreak were hospitalized. In both outbreaks, no 

antimicrobial resistance was predicted by WGS in isolates. 

Ground beef was a suspected vehicle in both outbreaks. When asked about exposure 

prior to illness, 80% (52/65) of respondents for the first outbreak and 86% (258/301) of 

respondents for the second outbreak reported consuming ground beef in the week prior 

to illness. In the first outbreak, three cattle isolates were collected by public health 

partners, one leftover ground beef, and one cecal isolate matched the outbreak strain 

by WGS. In the second, seven isolates from ground beef matched the outbreak strain. 

Traceback investigations were conducted for both outbreaks. In the first outbreak, 

traceback records did not conclusively converge on a single establishment. In the 

second outbreak, Establishment A was identified as the source of ground beef for 23/29 

(79%) cases. Of the seven isolates that matched the outbreak strain, three samples 

(two unopened, one leftover) also traced to Establishment A. The first outbreak did not 

lead to recall because no specific establishment could be linked; the second outbreak 

led to recall of over 12 million pounds of ground beef.

What’s Next?

 

Undercooking ground 

beef was reported in 

both outbreaks. In 2021, 

the National Cattleman’s 

Beef Association

published a report

highlighting the need for 

continued consumer 

food safety education. 

FSIS and the Centers 

for Disease Control and 

Prevention (CDC) will 

consider new ways to 

educate consumers 

regarding undercooking 

of ground beef and 

cross-contamination.

FSIS will continue to 

monitor strains causing 

reoccurring human 

illnesses to support

government-industry

collaboration for rapid

and effective response

during investigations. As 

appropriate, FSIS will 

involve industry and 

state partners in future 

investigations, including 

ones that may involve 

this reoccurring strain.

Collaboration

Reoccurring strains may 

be an indication of an 

environmental or animal 

reservoir for that 

pathogen. Industry and 

government partners are 

collaborating to develop 

a National Veterinary 

Accreditation Program

training module. The 

intent of the module is to 

promote adoption of 

preharvest practices that 

might enhance food 

safety through

preharvest pathogen 

reduction.

Consumers Preharvest
Helpful Links

• CDC Morbidity and Mortality Weekly Report Protracted Outbreak 

of Salmonella Newport Infections Linked to Ground Beef: Possible Role of Dairy 

Cows — 21 States, 2016–2017, April 20, 2018. 

• CDC Outbreak of Salmonella Infections Linked to Ground Beef Food Safety 

Alert, October 4, 2018 (final version March 22, 2019). 

• Association of Food and Drug Officials webpage: Leveraging Food Purchase 

History to Solve Foodborne Outbreaks.

• Shopper History Outbreak Partnership (2020): Shopper History: Best Practices 

for Use During Foodborne Illness Investigations.

• FSIS webpage: Resources for Public Health Partners (includes information 

helpful to FSIS during foodborne illness investigations). 

• USDA Animal and Plant Health Inspection Service National Veterinary 

Accreditation Program.

• National Cattlemen’s Beef Association (NCBA, 2021): Consumer Perceptions 

and Insights on Food Safety.