FDA Issue Report on Salmonella Outbreak Linked to Leafy Greens from Indoor Growing Facility

FDA released their report on a 2021 Salmonella outbreak that was linked to packaged leafy greens produced at a Controlled Environmental Agriculture (CEA) indoor hydroponic operation [a fancy indoor greenhouse].  The outbreak occurred in July and August of 2021 and was caused by Salmonella Typhimurium which infected 31 people and resulted in 4 hospitalizations.

One would think that product produced in a controlled setting would be free from pathogens.  However, there were many opportunities for contamination and a lack of control.  And an indoor greenhouse is not much different than a processing facility where controls are needed.  While a definitive source was not found, here is a brief summary of some of the issues"

• The operation stored its nutrient-rich growth media used in an outdoor location that was not adequately protected from potential sources of contamination such as animal intrusion, bird droppings, or water runoff.
• The use of production pond water, while not intended to be an issue with leafy greens final product, but control of the water was questioned and there were inadequate controls for the water itself, with FDA isolating a different strain of Salmonella (not the one involved in the outbreak.
• Harvesting equipment lacked adequate control, and condensate with the facility.
• Inadequate validation support for cooling greens after packaging.
• Issues with storm water retention pond in close proximity to the facility (25ft).  This pond did test positive for the outbreak strain.
• The firm did not adequately document that cleaning and sanitizing of equipment, tools, and buildings used in growing operations is routinely conducted in accordance with the firm’s procedures

FDA highlighted the recommendations that focused on the need to better understand the microbial risks and put in place better controls.
The full report can be found here - https://www.fda.gov/media/155402/download

Investigation Report: Factors Potentially Contributing to the  Contamination of Packaged Leafy

Greens Implicated in the Outbreak of Salmonella Typhimurium During the Summer of 2021

https://www.fda.gov/media/155402/download

Reason for Investigation
In July and August of 2021, the U.S. Food and Drug Administration (FDA), Centers for Disease 
Control and Prevention (CDC), and state partners conducted an outbreak investigation 
into a multistate outbreak of Salmonella Typhimurium linked to packaged leafy greens produced at a Controlled Environment Agriculture (CEA) indoor hydroponic operation.

Total Illnesses: 31
Hospitalizations: 4
Deaths: 0
First illness onset: June 10, 2021
Last illness onset: August 18, 2021
States with Cases: IL (18), MI (1), PA (2) WI (10)

The outbreak response investigation found:
1. The outbreak was associated with the consumption of packaged leafy greens from the  firm’s CEA indoor hydroponic operation; 26 of 27 (96%) patients reported consuming any leafy greens prior to illness onset, with 20 of 24 cases reporting consumption of prepackaged salads. This firm’s products were named specifically in 14 cases.
2. This outbreak was caused by Salmonella Typhimurium as determined by whole genome sequencing (WGS) analysis. The Salmonella Typhimurium isolates from ill consumers were closely related genetically; however, there were no product isolates for comparison.
3. Loyalty card data was received for nine cases. The information identified a common brand of packaged salads and the traceback investigation determined all of the points-ofservice (POS) were  supplied by the same hydroponic operation owned and operated by this firm. The firm’s salad products purchased by ill consumers were confirmed to be produced at the firm’s hydroponic operation.

FDA conducted an on-site produce safety investigation of the firm’s CEA operation, as part of the outbreak investigation