In May 2021, CDC public health and regulatory officials in several states, and the US Food and Drug Administration (FDA) investigated an outbreak of Salmonella Weltevreden infections linked to frozen cooked shrimp supplied by Avanti Frozen Foods. Nine people infected with the outbreak strain of Salmonella Weltevreden were reported from four states. Illnesses started on dates ranging from February 26, 2021 to July 17, 2021. Three people were hospitalized. No deaths were reported.

This outbreak was first detected by FDA when a sample of Avanti Frozen Foods shrimp collected for testing at import was found to be contaminated with Salmonella Weltevreden. Using the PulseNet system, investigators identified several people that are part of this outbreak by WGS. WGS showed that the Salmonella from the shrimp are closely related to bacteria from sick people.

FDA conducted a traceback investigation using purchase records from locations where six sick people bought shrimp. Based on their purchase locations and dates, FDA identified the common supplier of frozen precooked shrimp was Avanti Frozen Foods.

WGS analysis of bacteria from two food samples and nine people’s samples did not predict any antibiotic resistance. Standard antibiotic susceptibility testing of bacteria from three people’s samples by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory also found no resistance.

The outbreak was declared over on September 21, 2021.